Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/buffer.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 2002 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * Start bdflush() with kernel_thread not syscall - Paul Gortmaker, 12/95 |
| 9 | * |
| 10 | * Removed a lot of unnecessary code and simplified things now that |
| 11 | * the buffer cache isn't our primary cache - Andrew Tridgell 12/96 |
| 12 | * |
| 13 | * Speed up hash, lru, and free list operations. Use gfp() for allocating |
| 14 | * hash table, use SLAB cache for buffer heads. SMP threading. -DaveM |
| 15 | * |
| 16 | * Added 32k buffer block sizes - these are required older ARM systems. - RMK |
| 17 | * |
| 18 | * async buffer flushing, 1999 Andrea Arcangeli <andrea@suse.de> |
| 19 | */ |
| 20 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/kernel.h> |
| 22 | #include <linux/syscalls.h> |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/mm.h> |
| 25 | #include <linux/percpu.h> |
| 26 | #include <linux/slab.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 27 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <linux/blkdev.h> |
| 29 | #include <linux/file.h> |
| 30 | #include <linux/quotaops.h> |
| 31 | #include <linux/highmem.h> |
| 32 | #include <linux/module.h> |
| 33 | #include <linux/writeback.h> |
| 34 | #include <linux/hash.h> |
| 35 | #include <linux/suspend.h> |
| 36 | #include <linux/buffer_head.h> |
Andrew Morton | 55e829a | 2006-12-10 02:19:27 -0800 | [diff] [blame] | 37 | #include <linux/task_io_accounting_ops.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | #include <linux/bio.h> |
| 39 | #include <linux/notifier.h> |
| 40 | #include <linux/cpu.h> |
| 41 | #include <linux/bitops.h> |
| 42 | #include <linux/mpage.h> |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 43 | #include <linux/bit_spinlock.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | |
| 45 | static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | |
| 47 | #define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers) |
| 48 | |
| 49 | inline void |
| 50 | init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private) |
| 51 | { |
| 52 | bh->b_end_io = handler; |
| 53 | bh->b_private = private; |
| 54 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 55 | EXPORT_SYMBOL(init_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | |
| 57 | static int sync_buffer(void *word) |
| 58 | { |
| 59 | struct block_device *bd; |
| 60 | struct buffer_head *bh |
| 61 | = container_of(word, struct buffer_head, b_state); |
| 62 | |
| 63 | smp_mb(); |
| 64 | bd = bh->b_bdev; |
| 65 | if (bd) |
| 66 | blk_run_address_space(bd->bd_inode->i_mapping); |
| 67 | io_schedule(); |
| 68 | return 0; |
| 69 | } |
| 70 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 71 | void __lock_buffer(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | { |
| 73 | wait_on_bit_lock(&bh->b_state, BH_Lock, sync_buffer, |
| 74 | TASK_UNINTERRUPTIBLE); |
| 75 | } |
| 76 | EXPORT_SYMBOL(__lock_buffer); |
| 77 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 78 | void unlock_buffer(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | { |
Nick Piggin | 51b07fc | 2008-10-18 20:27:00 -0700 | [diff] [blame] | 80 | clear_bit_unlock(BH_Lock, &bh->b_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | smp_mb__after_clear_bit(); |
| 82 | wake_up_bit(&bh->b_state, BH_Lock); |
| 83 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 84 | EXPORT_SYMBOL(unlock_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | |
| 86 | /* |
| 87 | * Block until a buffer comes unlocked. This doesn't stop it |
| 88 | * from becoming locked again - you have to lock it yourself |
| 89 | * if you want to preserve its state. |
| 90 | */ |
| 91 | void __wait_on_buffer(struct buffer_head * bh) |
| 92 | { |
| 93 | wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE); |
| 94 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 95 | EXPORT_SYMBOL(__wait_on_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | |
| 97 | static void |
| 98 | __clear_page_buffers(struct page *page) |
| 99 | { |
| 100 | ClearPagePrivate(page); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 101 | set_page_private(page, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | page_cache_release(page); |
| 103 | } |
| 104 | |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 105 | |
| 106 | static int quiet_error(struct buffer_head *bh) |
| 107 | { |
| 108 | if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit()) |
| 109 | return 0; |
| 110 | return 1; |
| 111 | } |
| 112 | |
| 113 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | static void buffer_io_error(struct buffer_head *bh) |
| 115 | { |
| 116 | char b[BDEVNAME_SIZE]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n", |
| 118 | bdevname(bh->b_bdev, b), |
| 119 | (unsigned long long)bh->b_blocknr); |
| 120 | } |
| 121 | |
| 122 | /* |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 123 | * End-of-IO handler helper function which does not touch the bh after |
| 124 | * unlocking it. |
| 125 | * Note: unlock_buffer() sort-of does touch the bh after unlocking it, but |
| 126 | * a race there is benign: unlock_buffer() only use the bh's address for |
| 127 | * hashing after unlocking the buffer, so it doesn't actually touch the bh |
| 128 | * itself. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | */ |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 130 | static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | { |
| 132 | if (uptodate) { |
| 133 | set_buffer_uptodate(bh); |
| 134 | } else { |
| 135 | /* This happens, due to failed READA attempts. */ |
| 136 | clear_buffer_uptodate(bh); |
| 137 | } |
| 138 | unlock_buffer(bh); |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 139 | } |
| 140 | |
| 141 | /* |
| 142 | * Default synchronous end-of-IO handler.. Just mark it up-to-date and |
| 143 | * unlock the buffer. This is what ll_rw_block uses too. |
| 144 | */ |
| 145 | void end_buffer_read_sync(struct buffer_head *bh, int uptodate) |
| 146 | { |
| 147 | __end_buffer_read_notouch(bh, uptodate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | put_bh(bh); |
| 149 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 150 | EXPORT_SYMBOL(end_buffer_read_sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | |
| 152 | void end_buffer_write_sync(struct buffer_head *bh, int uptodate) |
| 153 | { |
| 154 | char b[BDEVNAME_SIZE]; |
| 155 | |
| 156 | if (uptodate) { |
| 157 | set_buffer_uptodate(bh); |
| 158 | } else { |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 159 | if (!buffer_eopnotsupp(bh) && !quiet_error(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | buffer_io_error(bh); |
| 161 | printk(KERN_WARNING "lost page write due to " |
| 162 | "I/O error on %s\n", |
| 163 | bdevname(bh->b_bdev, b)); |
| 164 | } |
| 165 | set_buffer_write_io_error(bh); |
| 166 | clear_buffer_uptodate(bh); |
| 167 | } |
| 168 | unlock_buffer(bh); |
| 169 | put_bh(bh); |
| 170 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 171 | EXPORT_SYMBOL(end_buffer_write_sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | |
| 173 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | * Various filesystems appear to want __find_get_block to be non-blocking. |
| 175 | * But it's the page lock which protects the buffers. To get around this, |
| 176 | * we get exclusion from try_to_free_buffers with the blockdev mapping's |
| 177 | * private_lock. |
| 178 | * |
| 179 | * Hack idea: for the blockdev mapping, i_bufferlist_lock contention |
| 180 | * may be quite high. This code could TryLock the page, and if that |
| 181 | * succeeds, there is no need to take private_lock. (But if |
| 182 | * private_lock is contended then so is mapping->tree_lock). |
| 183 | */ |
| 184 | static struct buffer_head * |
Coywolf Qi Hunt | 385fd4c | 2005-11-07 00:59:39 -0800 | [diff] [blame] | 185 | __find_get_block_slow(struct block_device *bdev, sector_t block) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | { |
| 187 | struct inode *bd_inode = bdev->bd_inode; |
| 188 | struct address_space *bd_mapping = bd_inode->i_mapping; |
| 189 | struct buffer_head *ret = NULL; |
| 190 | pgoff_t index; |
| 191 | struct buffer_head *bh; |
| 192 | struct buffer_head *head; |
| 193 | struct page *page; |
| 194 | int all_mapped = 1; |
| 195 | |
| 196 | index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits); |
| 197 | page = find_get_page(bd_mapping, index); |
| 198 | if (!page) |
| 199 | goto out; |
| 200 | |
| 201 | spin_lock(&bd_mapping->private_lock); |
| 202 | if (!page_has_buffers(page)) |
| 203 | goto out_unlock; |
| 204 | head = page_buffers(page); |
| 205 | bh = head; |
| 206 | do { |
Nikanth Karthikesan | 97f76d3 | 2009-04-02 16:56:46 -0700 | [diff] [blame] | 207 | if (!buffer_mapped(bh)) |
| 208 | all_mapped = 0; |
| 209 | else if (bh->b_blocknr == block) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | ret = bh; |
| 211 | get_bh(bh); |
| 212 | goto out_unlock; |
| 213 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | bh = bh->b_this_page; |
| 215 | } while (bh != head); |
| 216 | |
| 217 | /* we might be here because some of the buffers on this page are |
| 218 | * not mapped. This is due to various races between |
| 219 | * file io on the block device and getblk. It gets dealt with |
| 220 | * elsewhere, don't buffer_error if we had some unmapped buffers |
| 221 | */ |
| 222 | if (all_mapped) { |
| 223 | printk("__find_get_block_slow() failed. " |
| 224 | "block=%llu, b_blocknr=%llu\n", |
Badari Pulavarty | 205f87f | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 225 | (unsigned long long)block, |
| 226 | (unsigned long long)bh->b_blocknr); |
| 227 | printk("b_state=0x%08lx, b_size=%zu\n", |
| 228 | bh->b_state, bh->b_size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits); |
| 230 | } |
| 231 | out_unlock: |
| 232 | spin_unlock(&bd_mapping->private_lock); |
| 233 | page_cache_release(page); |
| 234 | out: |
| 235 | return ret; |
| 236 | } |
| 237 | |
| 238 | /* If invalidate_buffers() will trash dirty buffers, it means some kind |
| 239 | of fs corruption is going on. Trashing dirty data always imply losing |
| 240 | information that was supposed to be just stored on the physical layer |
| 241 | by the user. |
| 242 | |
| 243 | Thus invalidate_buffers in general usage is not allwowed to trash |
| 244 | dirty buffers. For example ioctl(FLSBLKBUF) expects dirty data to |
| 245 | be preserved. These buffers are simply skipped. |
| 246 | |
| 247 | We also skip buffers which are still in use. For example this can |
| 248 | happen if a userspace program is reading the block device. |
| 249 | |
| 250 | NOTE: In the case where the user removed a removable-media-disk even if |
| 251 | there's still dirty data not synced on disk (due a bug in the device driver |
| 252 | or due an error of the user), by not destroying the dirty buffers we could |
| 253 | generate corruption also on the next media inserted, thus a parameter is |
| 254 | necessary to handle this case in the most safe way possible (trying |
| 255 | to not corrupt also the new disk inserted with the data belonging to |
| 256 | the old now corrupted disk). Also for the ramdisk the natural thing |
| 257 | to do in order to release the ramdisk memory is to destroy dirty buffers. |
| 258 | |
| 259 | These are two special cases. Normal usage imply the device driver |
| 260 | to issue a sync on the device (without waiting I/O completion) and |
| 261 | then an invalidate_buffers call that doesn't trash dirty buffers. |
| 262 | |
| 263 | For handling cache coherency with the blkdev pagecache the 'update' case |
| 264 | is been introduced. It is needed to re-read from disk any pinned |
| 265 | buffer. NOTE: re-reading from disk is destructive so we can do it only |
| 266 | when we assume nobody is changing the buffercache under our I/O and when |
| 267 | we think the disk contains more recent information than the buffercache. |
| 268 | The update == 1 pass marks the buffers we need to update, the update == 2 |
| 269 | pass does the actual I/O. */ |
Peter Zijlstra | f98393a | 2007-05-06 14:49:54 -0700 | [diff] [blame] | 270 | void invalidate_bdev(struct block_device *bdev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | { |
Andrew Morton | 0e1dfc6 | 2006-07-30 03:03:28 -0700 | [diff] [blame] | 272 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
| 273 | |
| 274 | if (mapping->nrpages == 0) |
| 275 | return; |
| 276 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | invalidate_bh_lrus(); |
Tejun Heo | fa4b907 | 2010-05-15 20:09:27 +0200 | [diff] [blame] | 278 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ |
Andrew Morton | fc0ecff | 2007-02-10 01:45:39 -0800 | [diff] [blame] | 279 | invalidate_mapping_pages(mapping, 0, -1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 280 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 281 | EXPORT_SYMBOL(invalidate_bdev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | |
| 283 | /* |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 284 | * Kick the writeback threads then try to free up some ZONE_NORMAL memory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 285 | */ |
| 286 | static void free_more_memory(void) |
| 287 | { |
Mel Gorman | 19770b3 | 2008-04-28 02:12:18 -0700 | [diff] [blame] | 288 | struct zone *zone; |
Mel Gorman | 0e88460 | 2008-04-28 02:12:14 -0700 | [diff] [blame] | 289 | int nid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | |
Jens Axboe | 03ba378 | 2009-09-09 09:08:54 +0200 | [diff] [blame] | 291 | wakeup_flusher_threads(1024); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | yield(); |
| 293 | |
Mel Gorman | 0e88460 | 2008-04-28 02:12:14 -0700 | [diff] [blame] | 294 | for_each_online_node(nid) { |
Mel Gorman | 19770b3 | 2008-04-28 02:12:18 -0700 | [diff] [blame] | 295 | (void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS), |
| 296 | gfp_zone(GFP_NOFS), NULL, |
| 297 | &zone); |
| 298 | if (zone) |
Mel Gorman | 54a6eb5 | 2008-04-28 02:12:16 -0700 | [diff] [blame] | 299 | try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0, |
KAMEZAWA Hiroyuki | 327c0e9 | 2009-03-31 15:23:31 -0700 | [diff] [blame] | 300 | GFP_NOFS, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | } |
| 302 | } |
| 303 | |
| 304 | /* |
| 305 | * I/O completion handler for block_read_full_page() - pages |
| 306 | * which come unlocked at the end of I/O. |
| 307 | */ |
| 308 | static void end_buffer_async_read(struct buffer_head *bh, int uptodate) |
| 309 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | unsigned long flags; |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 311 | struct buffer_head *first; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | struct buffer_head *tmp; |
| 313 | struct page *page; |
| 314 | int page_uptodate = 1; |
| 315 | |
| 316 | BUG_ON(!buffer_async_read(bh)); |
| 317 | |
| 318 | page = bh->b_page; |
| 319 | if (uptodate) { |
| 320 | set_buffer_uptodate(bh); |
| 321 | } else { |
| 322 | clear_buffer_uptodate(bh); |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 323 | if (!quiet_error(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | buffer_io_error(bh); |
| 325 | SetPageError(page); |
| 326 | } |
| 327 | |
| 328 | /* |
| 329 | * Be _very_ careful from here on. Bad things can happen if |
| 330 | * two buffer heads end IO at almost the same time and both |
| 331 | * decide that the page is now completely done. |
| 332 | */ |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 333 | first = page_buffers(page); |
| 334 | local_irq_save(flags); |
| 335 | bit_spin_lock(BH_Uptodate_Lock, &first->b_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | clear_buffer_async_read(bh); |
| 337 | unlock_buffer(bh); |
| 338 | tmp = bh; |
| 339 | do { |
| 340 | if (!buffer_uptodate(tmp)) |
| 341 | page_uptodate = 0; |
| 342 | if (buffer_async_read(tmp)) { |
| 343 | BUG_ON(!buffer_locked(tmp)); |
| 344 | goto still_busy; |
| 345 | } |
| 346 | tmp = tmp->b_this_page; |
| 347 | } while (tmp != bh); |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 348 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 349 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | |
| 351 | /* |
| 352 | * If none of the buffers had errors and they are all |
| 353 | * uptodate then we can set the page uptodate. |
| 354 | */ |
| 355 | if (page_uptodate && !PageError(page)) |
| 356 | SetPageUptodate(page); |
| 357 | unlock_page(page); |
| 358 | return; |
| 359 | |
| 360 | still_busy: |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 361 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 362 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 363 | return; |
| 364 | } |
| 365 | |
| 366 | /* |
| 367 | * Completion handler for block_write_full_page() - pages which are unlocked |
| 368 | * during I/O, and which have PageWriteback cleared upon I/O completion. |
| 369 | */ |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 370 | void end_buffer_async_write(struct buffer_head *bh, int uptodate) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | { |
| 372 | char b[BDEVNAME_SIZE]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | unsigned long flags; |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 374 | struct buffer_head *first; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | struct buffer_head *tmp; |
| 376 | struct page *page; |
| 377 | |
| 378 | BUG_ON(!buffer_async_write(bh)); |
| 379 | |
| 380 | page = bh->b_page; |
| 381 | if (uptodate) { |
| 382 | set_buffer_uptodate(bh); |
| 383 | } else { |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 384 | if (!quiet_error(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | buffer_io_error(bh); |
| 386 | printk(KERN_WARNING "lost page write due to " |
| 387 | "I/O error on %s\n", |
| 388 | bdevname(bh->b_bdev, b)); |
| 389 | } |
| 390 | set_bit(AS_EIO, &page->mapping->flags); |
Jan Kara | 58ff407b | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 391 | set_buffer_write_io_error(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | clear_buffer_uptodate(bh); |
| 393 | SetPageError(page); |
| 394 | } |
| 395 | |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 396 | first = page_buffers(page); |
| 397 | local_irq_save(flags); |
| 398 | bit_spin_lock(BH_Uptodate_Lock, &first->b_state); |
| 399 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | clear_buffer_async_write(bh); |
| 401 | unlock_buffer(bh); |
| 402 | tmp = bh->b_this_page; |
| 403 | while (tmp != bh) { |
| 404 | if (buffer_async_write(tmp)) { |
| 405 | BUG_ON(!buffer_locked(tmp)); |
| 406 | goto still_busy; |
| 407 | } |
| 408 | tmp = tmp->b_this_page; |
| 409 | } |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 410 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 411 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | end_page_writeback(page); |
| 413 | return; |
| 414 | |
| 415 | still_busy: |
Nick Piggin | a397220 | 2005-07-07 17:56:56 -0700 | [diff] [blame] | 416 | bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); |
| 417 | local_irq_restore(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 418 | return; |
| 419 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 420 | EXPORT_SYMBOL(end_buffer_async_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 421 | |
| 422 | /* |
| 423 | * If a page's buffers are under async readin (end_buffer_async_read |
| 424 | * completion) then there is a possibility that another thread of |
| 425 | * control could lock one of the buffers after it has completed |
| 426 | * but while some of the other buffers have not completed. This |
| 427 | * locked buffer would confuse end_buffer_async_read() into not unlocking |
| 428 | * the page. So the absence of BH_Async_Read tells end_buffer_async_read() |
| 429 | * that this buffer is not under async I/O. |
| 430 | * |
| 431 | * The page comes unlocked when it has no locked buffer_async buffers |
| 432 | * left. |
| 433 | * |
| 434 | * PageLocked prevents anyone starting new async I/O reads any of |
| 435 | * the buffers. |
| 436 | * |
| 437 | * PageWriteback is used to prevent simultaneous writeout of the same |
| 438 | * page. |
| 439 | * |
| 440 | * PageLocked prevents anyone from starting writeback of a page which is |
| 441 | * under read I/O (PageWriteback is only ever set against a locked page). |
| 442 | */ |
| 443 | static void mark_buffer_async_read(struct buffer_head *bh) |
| 444 | { |
| 445 | bh->b_end_io = end_buffer_async_read; |
| 446 | set_buffer_async_read(bh); |
| 447 | } |
| 448 | |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 449 | static void mark_buffer_async_write_endio(struct buffer_head *bh, |
| 450 | bh_end_io_t *handler) |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 451 | { |
| 452 | bh->b_end_io = handler; |
| 453 | set_buffer_async_write(bh); |
| 454 | } |
| 455 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | void mark_buffer_async_write(struct buffer_head *bh) |
| 457 | { |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 458 | mark_buffer_async_write_endio(bh, end_buffer_async_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | } |
| 460 | EXPORT_SYMBOL(mark_buffer_async_write); |
| 461 | |
| 462 | |
| 463 | /* |
| 464 | * fs/buffer.c contains helper functions for buffer-backed address space's |
| 465 | * fsync functions. A common requirement for buffer-based filesystems is |
| 466 | * that certain data from the backing blockdev needs to be written out for |
| 467 | * a successful fsync(). For example, ext2 indirect blocks need to be |
| 468 | * written back and waited upon before fsync() returns. |
| 469 | * |
| 470 | * The functions mark_buffer_inode_dirty(), fsync_inode_buffers(), |
| 471 | * inode_has_buffers() and invalidate_inode_buffers() are provided for the |
| 472 | * management of a list of dependent buffers at ->i_mapping->private_list. |
| 473 | * |
| 474 | * Locking is a little subtle: try_to_free_buffers() will remove buffers |
| 475 | * from their controlling inode's queue when they are being freed. But |
| 476 | * try_to_free_buffers() will be operating against the *blockdev* mapping |
| 477 | * at the time, not against the S_ISREG file which depends on those buffers. |
| 478 | * So the locking for private_list is via the private_lock in the address_space |
| 479 | * which backs the buffers. Which is different from the address_space |
| 480 | * against which the buffers are listed. So for a particular address_space, |
| 481 | * mapping->private_lock does *not* protect mapping->private_list! In fact, |
| 482 | * mapping->private_list will always be protected by the backing blockdev's |
| 483 | * ->private_lock. |
| 484 | * |
| 485 | * Which introduces a requirement: all buffers on an address_space's |
| 486 | * ->private_list must be from the same address_space: the blockdev's. |
| 487 | * |
| 488 | * address_spaces which do not place buffers at ->private_list via these |
| 489 | * utility functions are free to use private_lock and private_list for |
| 490 | * whatever they want. The only requirement is that list_empty(private_list) |
| 491 | * be true at clear_inode() time. |
| 492 | * |
| 493 | * FIXME: clear_inode should not call invalidate_inode_buffers(). The |
| 494 | * filesystems should do that. invalidate_inode_buffers() should just go |
| 495 | * BUG_ON(!list_empty). |
| 496 | * |
| 497 | * FIXME: mark_buffer_dirty_inode() is a data-plane operation. It should |
| 498 | * take an address_space, not an inode. And it should be called |
| 499 | * mark_buffer_dirty_fsync() to clearly define why those buffers are being |
| 500 | * queued up. |
| 501 | * |
| 502 | * FIXME: mark_buffer_dirty_inode() doesn't need to add the buffer to the |
| 503 | * list if it is already on a list. Because if the buffer is on a list, |
| 504 | * it *must* already be on the right one. If not, the filesystem is being |
| 505 | * silly. This will save a ton of locking. But first we have to ensure |
| 506 | * that buffers are taken *off* the old inode's list when they are freed |
| 507 | * (presumably in truncate). That requires careful auditing of all |
| 508 | * filesystems (do it inside bforget()). It could also be done by bringing |
| 509 | * b_inode back. |
| 510 | */ |
| 511 | |
| 512 | /* |
| 513 | * The buffer's backing address_space's private_lock must be held |
| 514 | */ |
Thomas Petazzoni | dbacefc | 2008-07-29 22:33:47 -0700 | [diff] [blame] | 515 | static void __remove_assoc_queue(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | { |
| 517 | list_del_init(&bh->b_assoc_buffers); |
Jan Kara | 58ff407b | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 518 | WARN_ON(!bh->b_assoc_map); |
| 519 | if (buffer_write_io_error(bh)) |
| 520 | set_bit(AS_EIO, &bh->b_assoc_map->flags); |
| 521 | bh->b_assoc_map = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | } |
| 523 | |
| 524 | int inode_has_buffers(struct inode *inode) |
| 525 | { |
| 526 | return !list_empty(&inode->i_data.private_list); |
| 527 | } |
| 528 | |
| 529 | /* |
| 530 | * osync is designed to support O_SYNC io. It waits synchronously for |
| 531 | * all already-submitted IO to complete, but does not queue any new |
| 532 | * writes to the disk. |
| 533 | * |
| 534 | * To do O_SYNC writes, just queue the buffer writes with ll_rw_block as |
| 535 | * you dirty the buffers, and then use osync_inode_buffers to wait for |
| 536 | * completion. Any other dirty buffers which are not yet queued for |
| 537 | * write will not be flushed to disk by the osync. |
| 538 | */ |
| 539 | static int osync_buffers_list(spinlock_t *lock, struct list_head *list) |
| 540 | { |
| 541 | struct buffer_head *bh; |
| 542 | struct list_head *p; |
| 543 | int err = 0; |
| 544 | |
| 545 | spin_lock(lock); |
| 546 | repeat: |
| 547 | list_for_each_prev(p, list) { |
| 548 | bh = BH_ENTRY(p); |
| 549 | if (buffer_locked(bh)) { |
| 550 | get_bh(bh); |
| 551 | spin_unlock(lock); |
| 552 | wait_on_buffer(bh); |
| 553 | if (!buffer_uptodate(bh)) |
| 554 | err = -EIO; |
| 555 | brelse(bh); |
| 556 | spin_lock(lock); |
| 557 | goto repeat; |
| 558 | } |
| 559 | } |
| 560 | spin_unlock(lock); |
| 561 | return err; |
| 562 | } |
| 563 | |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 564 | static void do_thaw_one(struct super_block *sb, void *unused) |
| 565 | { |
| 566 | char b[BDEVNAME_SIZE]; |
| 567 | while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb)) |
| 568 | printk(KERN_WARNING "Emergency Thaw on %s\n", |
| 569 | bdevname(sb->s_bdev, b)); |
| 570 | } |
| 571 | |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 572 | static void do_thaw_all(struct work_struct *work) |
Eric Sandeen | c2d7543 | 2009-03-31 15:23:46 -0700 | [diff] [blame] | 573 | { |
Al Viro | 01a05b3 | 2010-03-23 06:06:58 -0400 | [diff] [blame] | 574 | iterate_supers(do_thaw_one, NULL); |
Jens Axboe | 053c525 | 2009-04-08 13:44:08 +0200 | [diff] [blame] | 575 | kfree(work); |
Eric Sandeen | c2d7543 | 2009-03-31 15:23:46 -0700 | [diff] [blame] | 576 | printk(KERN_WARNING "Emergency Thaw complete\n"); |
| 577 | } |
| 578 | |
| 579 | /** |
| 580 | * emergency_thaw_all -- forcibly thaw every frozen filesystem |
| 581 | * |
| 582 | * Used for emergency unfreeze of all filesystems via SysRq |
| 583 | */ |
| 584 | void emergency_thaw_all(void) |
| 585 | { |
Jens Axboe | 053c525 | 2009-04-08 13:44:08 +0200 | [diff] [blame] | 586 | struct work_struct *work; |
| 587 | |
| 588 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
| 589 | if (work) { |
| 590 | INIT_WORK(work, do_thaw_all); |
| 591 | schedule_work(work); |
| 592 | } |
Eric Sandeen | c2d7543 | 2009-03-31 15:23:46 -0700 | [diff] [blame] | 593 | } |
| 594 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | /** |
Randy Dunlap | 78a4a50 | 2008-02-29 22:02:31 -0800 | [diff] [blame] | 596 | * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 597 | * @mapping: the mapping which wants those buffers written |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 598 | * |
| 599 | * Starts I/O against the buffers at mapping->private_list, and waits upon |
| 600 | * that I/O. |
| 601 | * |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 602 | * Basically, this is a convenience function for fsync(). |
| 603 | * @mapping is a file or directory which needs those buffers to be written for |
| 604 | * a successful fsync(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | */ |
| 606 | int sync_mapping_buffers(struct address_space *mapping) |
| 607 | { |
| 608 | struct address_space *buffer_mapping = mapping->assoc_mapping; |
| 609 | |
| 610 | if (buffer_mapping == NULL || list_empty(&mapping->private_list)) |
| 611 | return 0; |
| 612 | |
| 613 | return fsync_buffers_list(&buffer_mapping->private_lock, |
| 614 | &mapping->private_list); |
| 615 | } |
| 616 | EXPORT_SYMBOL(sync_mapping_buffers); |
| 617 | |
| 618 | /* |
| 619 | * Called when we've recently written block `bblock', and it is known that |
| 620 | * `bblock' was for a buffer_boundary() buffer. This means that the block at |
| 621 | * `bblock + 1' is probably a dirty indirect block. Hunt it down and, if it's |
| 622 | * dirty, schedule it for IO. So that indirects merge nicely with their data. |
| 623 | */ |
| 624 | void write_boundary_block(struct block_device *bdev, |
| 625 | sector_t bblock, unsigned blocksize) |
| 626 | { |
| 627 | struct buffer_head *bh = __find_get_block(bdev, bblock + 1, blocksize); |
| 628 | if (bh) { |
| 629 | if (buffer_dirty(bh)) |
| 630 | ll_rw_block(WRITE, 1, &bh); |
| 631 | put_bh(bh); |
| 632 | } |
| 633 | } |
| 634 | |
| 635 | void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode) |
| 636 | { |
| 637 | struct address_space *mapping = inode->i_mapping; |
| 638 | struct address_space *buffer_mapping = bh->b_page->mapping; |
| 639 | |
| 640 | mark_buffer_dirty(bh); |
| 641 | if (!mapping->assoc_mapping) { |
| 642 | mapping->assoc_mapping = buffer_mapping; |
| 643 | } else { |
Eric Sesterhenn | e827f92 | 2006-03-26 18:24:46 +0200 | [diff] [blame] | 644 | BUG_ON(mapping->assoc_mapping != buffer_mapping); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | } |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 646 | if (!bh->b_assoc_map) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | spin_lock(&buffer_mapping->private_lock); |
| 648 | list_move_tail(&bh->b_assoc_buffers, |
| 649 | &mapping->private_list); |
Jan Kara | 58ff407b | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 650 | bh->b_assoc_map = mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | spin_unlock(&buffer_mapping->private_lock); |
| 652 | } |
| 653 | } |
| 654 | EXPORT_SYMBOL(mark_buffer_dirty_inode); |
| 655 | |
| 656 | /* |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 657 | * Mark the page dirty, and set it dirty in the radix tree, and mark the inode |
| 658 | * dirty. |
| 659 | * |
| 660 | * If warn is true, then emit a warning if the page is not uptodate and has |
| 661 | * not been truncated. |
| 662 | */ |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 663 | static void __set_page_dirty(struct page *page, |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 664 | struct address_space *mapping, int warn) |
| 665 | { |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 666 | spin_lock_irq(&mapping->tree_lock); |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 667 | if (page->mapping) { /* Race with truncate? */ |
| 668 | WARN_ON_ONCE(warn && !PageUptodate(page)); |
Edward Shishkin | e3a7cca | 2009-03-31 15:19:39 -0700 | [diff] [blame] | 669 | account_page_dirtied(page, mapping); |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 670 | radix_tree_tag_set(&mapping->page_tree, |
| 671 | page_index(page), PAGECACHE_TAG_DIRTY); |
| 672 | } |
Nick Piggin | 19fd623 | 2008-07-25 19:45:32 -0700 | [diff] [blame] | 673 | spin_unlock_irq(&mapping->tree_lock); |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 674 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 675 | } |
| 676 | |
| 677 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | * Add a page to the dirty page list. |
| 679 | * |
| 680 | * It is a sad fact of life that this function is called from several places |
| 681 | * deeply under spinlocking. It may not sleep. |
| 682 | * |
| 683 | * If the page has buffers, the uptodate buffers are set dirty, to preserve |
| 684 | * dirty-state coherency between the page and the buffers. It the page does |
| 685 | * not have buffers then when they are later attached they will all be set |
| 686 | * dirty. |
| 687 | * |
| 688 | * The buffers are dirtied before the page is dirtied. There's a small race |
| 689 | * window in which a writepage caller may see the page cleanness but not the |
| 690 | * buffer dirtiness. That's fine. If this code were to set the page dirty |
| 691 | * before the buffers, a concurrent writepage caller could clear the page dirty |
| 692 | * bit, see a bunch of clean buffers and we'd end up with dirty buffers/clean |
| 693 | * page on the dirty page list. |
| 694 | * |
| 695 | * We use private_lock to lock against try_to_free_buffers while using the |
| 696 | * page's buffer list. Also use this to protect against clean buffers being |
| 697 | * added to the page after it was set dirty. |
| 698 | * |
| 699 | * FIXME: may need to call ->reservepage here as well. That's rather up to the |
| 700 | * address_space though. |
| 701 | */ |
| 702 | int __set_page_dirty_buffers(struct page *page) |
| 703 | { |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 704 | int newly_dirty; |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 705 | struct address_space *mapping = page_mapping(page); |
Nick Piggin | ebf7a22 | 2006-10-10 04:36:54 +0200 | [diff] [blame] | 706 | |
| 707 | if (unlikely(!mapping)) |
| 708 | return !TestSetPageDirty(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | |
| 710 | spin_lock(&mapping->private_lock); |
| 711 | if (page_has_buffers(page)) { |
| 712 | struct buffer_head *head = page_buffers(page); |
| 713 | struct buffer_head *bh = head; |
| 714 | |
| 715 | do { |
| 716 | set_buffer_dirty(bh); |
| 717 | bh = bh->b_this_page; |
| 718 | } while (bh != head); |
| 719 | } |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 720 | newly_dirty = !TestSetPageDirty(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | spin_unlock(&mapping->private_lock); |
| 722 | |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 723 | if (newly_dirty) |
| 724 | __set_page_dirty(page, mapping, 1); |
| 725 | return newly_dirty; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | } |
| 727 | EXPORT_SYMBOL(__set_page_dirty_buffers); |
| 728 | |
| 729 | /* |
| 730 | * Write out and wait upon a list of buffers. |
| 731 | * |
| 732 | * We have conflicting pressures: we want to make sure that all |
| 733 | * initially dirty buffers get waited on, but that any subsequently |
| 734 | * dirtied buffers don't. After all, we don't want fsync to last |
| 735 | * forever if somebody is actively writing to the file. |
| 736 | * |
| 737 | * Do this in two main stages: first we copy dirty buffers to a |
| 738 | * temporary inode list, queueing the writes as we go. Then we clean |
| 739 | * up, waiting for those writes to complete. |
| 740 | * |
| 741 | * During this second stage, any subsequent updates to the file may end |
| 742 | * up refiling the buffer on the original inode's dirty list again, so |
| 743 | * there is a chance we will end up with a buffer queued for write but |
| 744 | * not yet completed on that list. So, as a final cleanup we go through |
| 745 | * the osync code to catch these locked, dirty buffers without requeuing |
| 746 | * any newly dirty buffers for write. |
| 747 | */ |
| 748 | static int fsync_buffers_list(spinlock_t *lock, struct list_head *list) |
| 749 | { |
| 750 | struct buffer_head *bh; |
| 751 | struct list_head tmp; |
Jens Axboe | 9cf6b72 | 2009-04-06 14:48:03 +0200 | [diff] [blame] | 752 | struct address_space *mapping, *prev_mapping = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 753 | int err = 0, err2; |
| 754 | |
| 755 | INIT_LIST_HEAD(&tmp); |
| 756 | |
| 757 | spin_lock(lock); |
| 758 | while (!list_empty(list)) { |
| 759 | bh = BH_ENTRY(list->next); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 760 | mapping = bh->b_assoc_map; |
Jan Kara | 58ff407b | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 761 | __remove_assoc_queue(bh); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 762 | /* Avoid race with mark_buffer_dirty_inode() which does |
| 763 | * a lockless check and we rely on seeing the dirty bit */ |
| 764 | smp_mb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 765 | if (buffer_dirty(bh) || buffer_locked(bh)) { |
| 766 | list_add(&bh->b_assoc_buffers, &tmp); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 767 | bh->b_assoc_map = mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | if (buffer_dirty(bh)) { |
| 769 | get_bh(bh); |
| 770 | spin_unlock(lock); |
| 771 | /* |
| 772 | * Ensure any pending I/O completes so that |
| 773 | * ll_rw_block() actually writes the current |
| 774 | * contents - it is a noop if I/O is still in |
| 775 | * flight on potentially older contents. |
| 776 | */ |
Jens Axboe | 9cf6b72 | 2009-04-06 14:48:03 +0200 | [diff] [blame] | 777 | ll_rw_block(SWRITE_SYNC_PLUG, 1, &bh); |
| 778 | |
| 779 | /* |
| 780 | * Kick off IO for the previous mapping. Note |
| 781 | * that we will not run the very last mapping, |
| 782 | * wait_on_buffer() will do that for us |
| 783 | * through sync_buffer(). |
| 784 | */ |
| 785 | if (prev_mapping && prev_mapping != mapping) |
| 786 | blk_run_address_space(prev_mapping); |
| 787 | prev_mapping = mapping; |
| 788 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 789 | brelse(bh); |
| 790 | spin_lock(lock); |
| 791 | } |
| 792 | } |
| 793 | } |
| 794 | |
| 795 | while (!list_empty(&tmp)) { |
| 796 | bh = BH_ENTRY(tmp.prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 797 | get_bh(bh); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 798 | mapping = bh->b_assoc_map; |
| 799 | __remove_assoc_queue(bh); |
| 800 | /* Avoid race with mark_buffer_dirty_inode() which does |
| 801 | * a lockless check and we rely on seeing the dirty bit */ |
| 802 | smp_mb(); |
| 803 | if (buffer_dirty(bh)) { |
| 804 | list_add(&bh->b_assoc_buffers, |
Jan Kara | e389229 | 2008-03-04 14:28:33 -0800 | [diff] [blame] | 805 | &mapping->private_list); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 806 | bh->b_assoc_map = mapping; |
| 807 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | spin_unlock(lock); |
| 809 | wait_on_buffer(bh); |
| 810 | if (!buffer_uptodate(bh)) |
| 811 | err = -EIO; |
| 812 | brelse(bh); |
| 813 | spin_lock(lock); |
| 814 | } |
| 815 | |
| 816 | spin_unlock(lock); |
| 817 | err2 = osync_buffers_list(lock, list); |
| 818 | if (err) |
| 819 | return err; |
| 820 | else |
| 821 | return err2; |
| 822 | } |
| 823 | |
| 824 | /* |
| 825 | * Invalidate any and all dirty buffers on a given inode. We are |
| 826 | * probably unmounting the fs, but that doesn't mean we have already |
| 827 | * done a sync(). Just drop the buffers from the inode list. |
| 828 | * |
| 829 | * NOTE: we take the inode's blockdev's mapping's private_lock. Which |
| 830 | * assumes that all the buffers are against the blockdev. Not true |
| 831 | * for reiserfs. |
| 832 | */ |
| 833 | void invalidate_inode_buffers(struct inode *inode) |
| 834 | { |
| 835 | if (inode_has_buffers(inode)) { |
| 836 | struct address_space *mapping = &inode->i_data; |
| 837 | struct list_head *list = &mapping->private_list; |
| 838 | struct address_space *buffer_mapping = mapping->assoc_mapping; |
| 839 | |
| 840 | spin_lock(&buffer_mapping->private_lock); |
| 841 | while (!list_empty(list)) |
| 842 | __remove_assoc_queue(BH_ENTRY(list->next)); |
| 843 | spin_unlock(&buffer_mapping->private_lock); |
| 844 | } |
| 845 | } |
Jan Kara | 52b19ac | 2008-09-23 18:24:08 +0200 | [diff] [blame] | 846 | EXPORT_SYMBOL(invalidate_inode_buffers); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 847 | |
| 848 | /* |
| 849 | * Remove any clean buffers from the inode's buffer list. This is called |
| 850 | * when we're trying to free the inode itself. Those buffers can pin it. |
| 851 | * |
| 852 | * Returns true if all buffers were removed. |
| 853 | */ |
| 854 | int remove_inode_buffers(struct inode *inode) |
| 855 | { |
| 856 | int ret = 1; |
| 857 | |
| 858 | if (inode_has_buffers(inode)) { |
| 859 | struct address_space *mapping = &inode->i_data; |
| 860 | struct list_head *list = &mapping->private_list; |
| 861 | struct address_space *buffer_mapping = mapping->assoc_mapping; |
| 862 | |
| 863 | spin_lock(&buffer_mapping->private_lock); |
| 864 | while (!list_empty(list)) { |
| 865 | struct buffer_head *bh = BH_ENTRY(list->next); |
| 866 | if (buffer_dirty(bh)) { |
| 867 | ret = 0; |
| 868 | break; |
| 869 | } |
| 870 | __remove_assoc_queue(bh); |
| 871 | } |
| 872 | spin_unlock(&buffer_mapping->private_lock); |
| 873 | } |
| 874 | return ret; |
| 875 | } |
| 876 | |
| 877 | /* |
| 878 | * Create the appropriate buffers when given a page for data area and |
| 879 | * the size of each buffer.. Use the bh->b_this_page linked list to |
| 880 | * follow the buffers created. Return NULL if unable to create more |
| 881 | * buffers. |
| 882 | * |
| 883 | * The retry flag is used to differentiate async IO (paging, swapping) |
| 884 | * which may not fail from ordinary buffer allocations. |
| 885 | */ |
| 886 | struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, |
| 887 | int retry) |
| 888 | { |
| 889 | struct buffer_head *bh, *head; |
| 890 | long offset; |
| 891 | |
| 892 | try_again: |
| 893 | head = NULL; |
| 894 | offset = PAGE_SIZE; |
| 895 | while ((offset -= size) >= 0) { |
| 896 | bh = alloc_buffer_head(GFP_NOFS); |
| 897 | if (!bh) |
| 898 | goto no_grow; |
| 899 | |
| 900 | bh->b_bdev = NULL; |
| 901 | bh->b_this_page = head; |
| 902 | bh->b_blocknr = -1; |
| 903 | head = bh; |
| 904 | |
| 905 | bh->b_state = 0; |
| 906 | atomic_set(&bh->b_count, 0); |
Chris Mason | fc5cd58 | 2006-02-01 03:06:48 -0800 | [diff] [blame] | 907 | bh->b_private = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | bh->b_size = size; |
| 909 | |
| 910 | /* Link the buffer to its page */ |
| 911 | set_bh_page(bh, page, offset); |
| 912 | |
Nathan Scott | 01ffe33 | 2006-01-17 09:02:07 +1100 | [diff] [blame] | 913 | init_buffer(bh, NULL, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 914 | } |
| 915 | return head; |
| 916 | /* |
| 917 | * In case anything failed, we just free everything we got. |
| 918 | */ |
| 919 | no_grow: |
| 920 | if (head) { |
| 921 | do { |
| 922 | bh = head; |
| 923 | head = head->b_this_page; |
| 924 | free_buffer_head(bh); |
| 925 | } while (head); |
| 926 | } |
| 927 | |
| 928 | /* |
| 929 | * Return failure for non-async IO requests. Async IO requests |
| 930 | * are not allowed to fail, so we have to wait until buffer heads |
| 931 | * become available. But we don't want tasks sleeping with |
| 932 | * partially complete buffers, so all were released above. |
| 933 | */ |
| 934 | if (!retry) |
| 935 | return NULL; |
| 936 | |
| 937 | /* We're _really_ low on memory. Now we just |
| 938 | * wait for old buffer heads to become free due to |
| 939 | * finishing IO. Since this is an async request and |
| 940 | * the reserve list is empty, we're sure there are |
| 941 | * async buffer heads in use. |
| 942 | */ |
| 943 | free_more_memory(); |
| 944 | goto try_again; |
| 945 | } |
| 946 | EXPORT_SYMBOL_GPL(alloc_page_buffers); |
| 947 | |
| 948 | static inline void |
| 949 | link_dev_buffers(struct page *page, struct buffer_head *head) |
| 950 | { |
| 951 | struct buffer_head *bh, *tail; |
| 952 | |
| 953 | bh = head; |
| 954 | do { |
| 955 | tail = bh; |
| 956 | bh = bh->b_this_page; |
| 957 | } while (bh); |
| 958 | tail->b_this_page = head; |
| 959 | attach_page_buffers(page, head); |
| 960 | } |
| 961 | |
| 962 | /* |
| 963 | * Initialise the state of a blockdev page's buffers. |
| 964 | */ |
| 965 | static void |
| 966 | init_page_buffers(struct page *page, struct block_device *bdev, |
| 967 | sector_t block, int size) |
| 968 | { |
| 969 | struct buffer_head *head = page_buffers(page); |
| 970 | struct buffer_head *bh = head; |
| 971 | int uptodate = PageUptodate(page); |
| 972 | |
| 973 | do { |
| 974 | if (!buffer_mapped(bh)) { |
| 975 | init_buffer(bh, NULL, NULL); |
| 976 | bh->b_bdev = bdev; |
| 977 | bh->b_blocknr = block; |
| 978 | if (uptodate) |
| 979 | set_buffer_uptodate(bh); |
| 980 | set_buffer_mapped(bh); |
| 981 | } |
| 982 | block++; |
| 983 | bh = bh->b_this_page; |
| 984 | } while (bh != head); |
| 985 | } |
| 986 | |
| 987 | /* |
| 988 | * Create the page-cache page that contains the requested block. |
| 989 | * |
| 990 | * This is user purely for blockdev mappings. |
| 991 | */ |
| 992 | static struct page * |
| 993 | grow_dev_page(struct block_device *bdev, sector_t block, |
| 994 | pgoff_t index, int size) |
| 995 | { |
| 996 | struct inode *inode = bdev->bd_inode; |
| 997 | struct page *page; |
| 998 | struct buffer_head *bh; |
| 999 | |
Christoph Lameter | ea12589 | 2007-05-16 22:11:21 -0700 | [diff] [blame] | 1000 | page = find_or_create_page(inode->i_mapping, index, |
Mel Gorman | 769848c | 2007-07-17 04:03:05 -0700 | [diff] [blame] | 1001 | (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1002 | if (!page) |
| 1003 | return NULL; |
| 1004 | |
Eric Sesterhenn | e827f92 | 2006-03-26 18:24:46 +0200 | [diff] [blame] | 1005 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1006 | |
| 1007 | if (page_has_buffers(page)) { |
| 1008 | bh = page_buffers(page); |
| 1009 | if (bh->b_size == size) { |
| 1010 | init_page_buffers(page, bdev, block, size); |
| 1011 | return page; |
| 1012 | } |
| 1013 | if (!try_to_free_buffers(page)) |
| 1014 | goto failed; |
| 1015 | } |
| 1016 | |
| 1017 | /* |
| 1018 | * Allocate some buffers for this page |
| 1019 | */ |
| 1020 | bh = alloc_page_buffers(page, size, 0); |
| 1021 | if (!bh) |
| 1022 | goto failed; |
| 1023 | |
| 1024 | /* |
| 1025 | * Link the page to the buffers and initialise them. Take the |
| 1026 | * lock to be atomic wrt __find_get_block(), which does not |
| 1027 | * run under the page lock. |
| 1028 | */ |
| 1029 | spin_lock(&inode->i_mapping->private_lock); |
| 1030 | link_dev_buffers(page, bh); |
| 1031 | init_page_buffers(page, bdev, block, size); |
| 1032 | spin_unlock(&inode->i_mapping->private_lock); |
| 1033 | return page; |
| 1034 | |
| 1035 | failed: |
| 1036 | BUG(); |
| 1037 | unlock_page(page); |
| 1038 | page_cache_release(page); |
| 1039 | return NULL; |
| 1040 | } |
| 1041 | |
| 1042 | /* |
| 1043 | * Create buffers for the specified block device block's page. If |
| 1044 | * that page was dirty, the buffers are set dirty also. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1045 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1046 | static int |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1047 | grow_buffers(struct block_device *bdev, sector_t block, int size) |
| 1048 | { |
| 1049 | struct page *page; |
| 1050 | pgoff_t index; |
| 1051 | int sizebits; |
| 1052 | |
| 1053 | sizebits = -1; |
| 1054 | do { |
| 1055 | sizebits++; |
| 1056 | } while ((size << sizebits) < PAGE_SIZE); |
| 1057 | |
| 1058 | index = block >> sizebits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1060 | /* |
| 1061 | * Check for a block which wants to lie outside our maximum possible |
| 1062 | * pagecache index. (this comparison is done using sector_t types). |
| 1063 | */ |
| 1064 | if (unlikely(index != block >> sizebits)) { |
| 1065 | char b[BDEVNAME_SIZE]; |
| 1066 | |
| 1067 | printk(KERN_ERR "%s: requested out-of-range block %llu for " |
| 1068 | "device %s\n", |
Harvey Harrison | 8e24eea | 2008-04-30 00:55:09 -0700 | [diff] [blame] | 1069 | __func__, (unsigned long long)block, |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1070 | bdevname(bdev, b)); |
| 1071 | return -EIO; |
| 1072 | } |
| 1073 | block = index << sizebits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1074 | /* Create a page with the proper size buffers.. */ |
| 1075 | page = grow_dev_page(bdev, block, index, size); |
| 1076 | if (!page) |
| 1077 | return 0; |
| 1078 | unlock_page(page); |
| 1079 | page_cache_release(page); |
| 1080 | return 1; |
| 1081 | } |
| 1082 | |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 1083 | static struct buffer_head * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1084 | __getblk_slow(struct block_device *bdev, sector_t block, int size) |
| 1085 | { |
| 1086 | /* Size must be multiple of hard sectorsize */ |
Martin K. Petersen | e1defc4 | 2009-05-22 17:17:49 -0400 | [diff] [blame] | 1087 | if (unlikely(size & (bdev_logical_block_size(bdev)-1) || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1088 | (size < 512 || size > PAGE_SIZE))) { |
| 1089 | printk(KERN_ERR "getblk(): invalid block size %d requested\n", |
| 1090 | size); |
Martin K. Petersen | e1defc4 | 2009-05-22 17:17:49 -0400 | [diff] [blame] | 1091 | printk(KERN_ERR "logical block size: %d\n", |
| 1092 | bdev_logical_block_size(bdev)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1093 | |
| 1094 | dump_stack(); |
| 1095 | return NULL; |
| 1096 | } |
| 1097 | |
| 1098 | for (;;) { |
| 1099 | struct buffer_head * bh; |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1100 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1101 | |
| 1102 | bh = __find_get_block(bdev, block, size); |
| 1103 | if (bh) |
| 1104 | return bh; |
| 1105 | |
Andrew Morton | e565793 | 2006-10-11 01:21:46 -0700 | [diff] [blame] | 1106 | ret = grow_buffers(bdev, block, size); |
| 1107 | if (ret < 0) |
| 1108 | return NULL; |
| 1109 | if (ret == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1110 | free_more_memory(); |
| 1111 | } |
| 1112 | } |
| 1113 | |
| 1114 | /* |
| 1115 | * The relationship between dirty buffers and dirty pages: |
| 1116 | * |
| 1117 | * Whenever a page has any dirty buffers, the page's dirty bit is set, and |
| 1118 | * the page is tagged dirty in its radix tree. |
| 1119 | * |
| 1120 | * At all times, the dirtiness of the buffers represents the dirtiness of |
| 1121 | * subsections of the page. If the page has buffers, the page dirty bit is |
| 1122 | * merely a hint about the true dirty state. |
| 1123 | * |
| 1124 | * When a page is set dirty in its entirety, all its buffers are marked dirty |
| 1125 | * (if the page has buffers). |
| 1126 | * |
| 1127 | * When a buffer is marked dirty, its page is dirtied, but the page's other |
| 1128 | * buffers are not. |
| 1129 | * |
| 1130 | * Also. When blockdev buffers are explicitly read with bread(), they |
| 1131 | * individually become uptodate. But their backing page remains not |
| 1132 | * uptodate - even if all of its buffers are uptodate. A subsequent |
| 1133 | * block_read_full_page() against that page will discover all the uptodate |
| 1134 | * buffers, will set the page uptodate and will perform no I/O. |
| 1135 | */ |
| 1136 | |
| 1137 | /** |
| 1138 | * mark_buffer_dirty - mark a buffer_head as needing writeout |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 1139 | * @bh: the buffer_head to mark dirty |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1140 | * |
| 1141 | * mark_buffer_dirty() will set the dirty bit against the buffer, then set its |
| 1142 | * backing page dirty, then tag the page as dirty in its address_space's radix |
| 1143 | * tree and then attach the address_space's inode to its superblock's dirty |
| 1144 | * inode list. |
| 1145 | * |
| 1146 | * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock, |
| 1147 | * mapping->tree_lock and the global inode_lock. |
| 1148 | */ |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 1149 | void mark_buffer_dirty(struct buffer_head *bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1150 | { |
Nick Piggin | 787d2214 | 2007-07-17 04:03:34 -0700 | [diff] [blame] | 1151 | WARN_ON_ONCE(!buffer_uptodate(bh)); |
Linus Torvalds | 1be62dc | 2008-04-04 14:38:17 -0700 | [diff] [blame] | 1152 | |
| 1153 | /* |
| 1154 | * Very *carefully* optimize the it-is-already-dirty case. |
| 1155 | * |
| 1156 | * Don't let the final "is it dirty" escape to before we |
| 1157 | * perhaps modified the buffer. |
| 1158 | */ |
| 1159 | if (buffer_dirty(bh)) { |
| 1160 | smp_mb(); |
| 1161 | if (buffer_dirty(bh)) |
| 1162 | return; |
| 1163 | } |
| 1164 | |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 1165 | if (!test_set_buffer_dirty(bh)) { |
| 1166 | struct page *page = bh->b_page; |
Linus Torvalds | 8e9d78e | 2009-08-21 17:40:08 -0700 | [diff] [blame] | 1167 | if (!TestSetPageDirty(page)) { |
| 1168 | struct address_space *mapping = page_mapping(page); |
| 1169 | if (mapping) |
| 1170 | __set_page_dirty(page, mapping, 0); |
| 1171 | } |
Linus Torvalds | a8e7d49 | 2009-03-19 11:32:05 -0700 | [diff] [blame] | 1172 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1173 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 1174 | EXPORT_SYMBOL(mark_buffer_dirty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1175 | |
| 1176 | /* |
| 1177 | * Decrement a buffer_head's reference count. If all buffers against a page |
| 1178 | * have zero reference count, are clean and unlocked, and if the page is clean |
| 1179 | * and unlocked then try_to_free_buffers() may strip the buffers from the page |
| 1180 | * in preparation for freeing it (sometimes, rarely, buffers are removed from |
| 1181 | * a page but it ends up not being freed, and buffers may later be reattached). |
| 1182 | */ |
| 1183 | void __brelse(struct buffer_head * buf) |
| 1184 | { |
| 1185 | if (atomic_read(&buf->b_count)) { |
| 1186 | put_bh(buf); |
| 1187 | return; |
| 1188 | } |
Arjan van de Ven | 5c752ad | 2008-07-25 19:45:40 -0700 | [diff] [blame] | 1189 | WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1190 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 1191 | EXPORT_SYMBOL(__brelse); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1192 | |
| 1193 | /* |
| 1194 | * bforget() is like brelse(), except it discards any |
| 1195 | * potentially dirty data. |
| 1196 | */ |
| 1197 | void __bforget(struct buffer_head *bh) |
| 1198 | { |
| 1199 | clear_buffer_dirty(bh); |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 1200 | if (bh->b_assoc_map) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1201 | struct address_space *buffer_mapping = bh->b_page->mapping; |
| 1202 | |
| 1203 | spin_lock(&buffer_mapping->private_lock); |
| 1204 | list_del_init(&bh->b_assoc_buffers); |
Jan Kara | 58ff407b | 2006-10-17 00:10:19 -0700 | [diff] [blame] | 1205 | bh->b_assoc_map = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1206 | spin_unlock(&buffer_mapping->private_lock); |
| 1207 | } |
| 1208 | __brelse(bh); |
| 1209 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 1210 | EXPORT_SYMBOL(__bforget); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1211 | |
| 1212 | static struct buffer_head *__bread_slow(struct buffer_head *bh) |
| 1213 | { |
| 1214 | lock_buffer(bh); |
| 1215 | if (buffer_uptodate(bh)) { |
| 1216 | unlock_buffer(bh); |
| 1217 | return bh; |
| 1218 | } else { |
| 1219 | get_bh(bh); |
| 1220 | bh->b_end_io = end_buffer_read_sync; |
| 1221 | submit_bh(READ, bh); |
| 1222 | wait_on_buffer(bh); |
| 1223 | if (buffer_uptodate(bh)) |
| 1224 | return bh; |
| 1225 | } |
| 1226 | brelse(bh); |
| 1227 | return NULL; |
| 1228 | } |
| 1229 | |
| 1230 | /* |
| 1231 | * Per-cpu buffer LRU implementation. To reduce the cost of __find_get_block(). |
| 1232 | * The bhs[] array is sorted - newest buffer is at bhs[0]. Buffers have their |
| 1233 | * refcount elevated by one when they're in an LRU. A buffer can only appear |
| 1234 | * once in a particular CPU's LRU. A single buffer can be present in multiple |
| 1235 | * CPU's LRUs at the same time. |
| 1236 | * |
| 1237 | * This is a transparent caching front-end to sb_bread(), sb_getblk() and |
| 1238 | * sb_find_get_block(). |
| 1239 | * |
| 1240 | * The LRUs themselves only need locking against invalidate_bh_lrus. We use |
| 1241 | * a local interrupt disable for that. |
| 1242 | */ |
| 1243 | |
| 1244 | #define BH_LRU_SIZE 8 |
| 1245 | |
| 1246 | struct bh_lru { |
| 1247 | struct buffer_head *bhs[BH_LRU_SIZE]; |
| 1248 | }; |
| 1249 | |
| 1250 | static DEFINE_PER_CPU(struct bh_lru, bh_lrus) = {{ NULL }}; |
| 1251 | |
| 1252 | #ifdef CONFIG_SMP |
| 1253 | #define bh_lru_lock() local_irq_disable() |
| 1254 | #define bh_lru_unlock() local_irq_enable() |
| 1255 | #else |
| 1256 | #define bh_lru_lock() preempt_disable() |
| 1257 | #define bh_lru_unlock() preempt_enable() |
| 1258 | #endif |
| 1259 | |
| 1260 | static inline void check_irqs_on(void) |
| 1261 | { |
| 1262 | #ifdef irqs_disabled |
| 1263 | BUG_ON(irqs_disabled()); |
| 1264 | #endif |
| 1265 | } |
| 1266 | |
| 1267 | /* |
| 1268 | * The LRU management algorithm is dopey-but-simple. Sorry. |
| 1269 | */ |
| 1270 | static void bh_lru_install(struct buffer_head *bh) |
| 1271 | { |
| 1272 | struct buffer_head *evictee = NULL; |
| 1273 | struct bh_lru *lru; |
| 1274 | |
| 1275 | check_irqs_on(); |
| 1276 | bh_lru_lock(); |
| 1277 | lru = &__get_cpu_var(bh_lrus); |
| 1278 | if (lru->bhs[0] != bh) { |
| 1279 | struct buffer_head *bhs[BH_LRU_SIZE]; |
| 1280 | int in; |
| 1281 | int out = 0; |
| 1282 | |
| 1283 | get_bh(bh); |
| 1284 | bhs[out++] = bh; |
| 1285 | for (in = 0; in < BH_LRU_SIZE; in++) { |
| 1286 | struct buffer_head *bh2 = lru->bhs[in]; |
| 1287 | |
| 1288 | if (bh2 == bh) { |
| 1289 | __brelse(bh2); |
| 1290 | } else { |
| 1291 | if (out >= BH_LRU_SIZE) { |
| 1292 | BUG_ON(evictee != NULL); |
| 1293 | evictee = bh2; |
| 1294 | } else { |
| 1295 | bhs[out++] = bh2; |
| 1296 | } |
| 1297 | } |
| 1298 | } |
| 1299 | while (out < BH_LRU_SIZE) |
| 1300 | bhs[out++] = NULL; |
| 1301 | memcpy(lru->bhs, bhs, sizeof(bhs)); |
| 1302 | } |
| 1303 | bh_lru_unlock(); |
| 1304 | |
| 1305 | if (evictee) |
| 1306 | __brelse(evictee); |
| 1307 | } |
| 1308 | |
| 1309 | /* |
| 1310 | * Look up the bh in this cpu's LRU. If it's there, move it to the head. |
| 1311 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1312 | static struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1313 | lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1314 | { |
| 1315 | struct buffer_head *ret = NULL; |
| 1316 | struct bh_lru *lru; |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1317 | unsigned int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1318 | |
| 1319 | check_irqs_on(); |
| 1320 | bh_lru_lock(); |
| 1321 | lru = &__get_cpu_var(bh_lrus); |
| 1322 | for (i = 0; i < BH_LRU_SIZE; i++) { |
| 1323 | struct buffer_head *bh = lru->bhs[i]; |
| 1324 | |
| 1325 | if (bh && bh->b_bdev == bdev && |
| 1326 | bh->b_blocknr == block && bh->b_size == size) { |
| 1327 | if (i) { |
| 1328 | while (i) { |
| 1329 | lru->bhs[i] = lru->bhs[i - 1]; |
| 1330 | i--; |
| 1331 | } |
| 1332 | lru->bhs[0] = bh; |
| 1333 | } |
| 1334 | get_bh(bh); |
| 1335 | ret = bh; |
| 1336 | break; |
| 1337 | } |
| 1338 | } |
| 1339 | bh_lru_unlock(); |
| 1340 | return ret; |
| 1341 | } |
| 1342 | |
| 1343 | /* |
| 1344 | * Perform a pagecache lookup for the matching buffer. If it's there, refresh |
| 1345 | * it in the LRU and mark it as accessed. If it is not present then return |
| 1346 | * NULL |
| 1347 | */ |
| 1348 | struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1349 | __find_get_block(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1350 | { |
| 1351 | struct buffer_head *bh = lookup_bh_lru(bdev, block, size); |
| 1352 | |
| 1353 | if (bh == NULL) { |
Coywolf Qi Hunt | 385fd4c | 2005-11-07 00:59:39 -0800 | [diff] [blame] | 1354 | bh = __find_get_block_slow(bdev, block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1355 | if (bh) |
| 1356 | bh_lru_install(bh); |
| 1357 | } |
| 1358 | if (bh) |
| 1359 | touch_buffer(bh); |
| 1360 | return bh; |
| 1361 | } |
| 1362 | EXPORT_SYMBOL(__find_get_block); |
| 1363 | |
| 1364 | /* |
| 1365 | * __getblk will locate (and, if necessary, create) the buffer_head |
| 1366 | * which corresponds to the passed block_device, block and size. The |
| 1367 | * returned buffer has its reference count incremented. |
| 1368 | * |
| 1369 | * __getblk() cannot fail - it just keeps trying. If you pass it an |
| 1370 | * illegal block number, __getblk() will happily return a buffer_head |
| 1371 | * which represents the non-existent block. Very weird. |
| 1372 | * |
| 1373 | * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() |
| 1374 | * attempt is failing. FIXME, perhaps? |
| 1375 | */ |
| 1376 | struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1377 | __getblk(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1378 | { |
| 1379 | struct buffer_head *bh = __find_get_block(bdev, block, size); |
| 1380 | |
| 1381 | might_sleep(); |
| 1382 | if (bh == NULL) |
| 1383 | bh = __getblk_slow(bdev, block, size); |
| 1384 | return bh; |
| 1385 | } |
| 1386 | EXPORT_SYMBOL(__getblk); |
| 1387 | |
| 1388 | /* |
| 1389 | * Do async read-ahead on a buffer.. |
| 1390 | */ |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1391 | void __breadahead(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1392 | { |
| 1393 | struct buffer_head *bh = __getblk(bdev, block, size); |
Andrew Morton | a3e713b | 2005-10-30 15:03:15 -0800 | [diff] [blame] | 1394 | if (likely(bh)) { |
| 1395 | ll_rw_block(READA, 1, &bh); |
| 1396 | brelse(bh); |
| 1397 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1398 | } |
| 1399 | EXPORT_SYMBOL(__breadahead); |
| 1400 | |
| 1401 | /** |
| 1402 | * __bread() - reads a specified block and returns the bh |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 1403 | * @bdev: the block_device to read from |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1404 | * @block: number of block |
| 1405 | * @size: size (in bytes) to read |
| 1406 | * |
| 1407 | * Reads a specified block, and returns buffer head that contains it. |
| 1408 | * It returns NULL if the block was unreadable. |
| 1409 | */ |
| 1410 | struct buffer_head * |
Tomasz Kvarsin | 3991d3b | 2007-02-12 00:52:14 -0800 | [diff] [blame] | 1411 | __bread(struct block_device *bdev, sector_t block, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1412 | { |
| 1413 | struct buffer_head *bh = __getblk(bdev, block, size); |
| 1414 | |
Andrew Morton | a3e713b | 2005-10-30 15:03:15 -0800 | [diff] [blame] | 1415 | if (likely(bh) && !buffer_uptodate(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1416 | bh = __bread_slow(bh); |
| 1417 | return bh; |
| 1418 | } |
| 1419 | EXPORT_SYMBOL(__bread); |
| 1420 | |
| 1421 | /* |
| 1422 | * invalidate_bh_lrus() is called rarely - but not only at unmount. |
| 1423 | * This doesn't race because it runs in each cpu either in irq |
| 1424 | * or with preempt disabled. |
| 1425 | */ |
| 1426 | static void invalidate_bh_lru(void *arg) |
| 1427 | { |
| 1428 | struct bh_lru *b = &get_cpu_var(bh_lrus); |
| 1429 | int i; |
| 1430 | |
| 1431 | for (i = 0; i < BH_LRU_SIZE; i++) { |
| 1432 | brelse(b->bhs[i]); |
| 1433 | b->bhs[i] = NULL; |
| 1434 | } |
| 1435 | put_cpu_var(bh_lrus); |
| 1436 | } |
| 1437 | |
Peter Zijlstra | f9a1439 | 2007-05-06 14:49:55 -0700 | [diff] [blame] | 1438 | void invalidate_bh_lrus(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1439 | { |
Jens Axboe | 15c8b6c | 2008-05-09 09:39:44 +0200 | [diff] [blame] | 1440 | on_each_cpu(invalidate_bh_lru, NULL, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1441 | } |
Nick Piggin | 9db5579 | 2008-02-08 04:19:49 -0800 | [diff] [blame] | 1442 | EXPORT_SYMBOL_GPL(invalidate_bh_lrus); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1443 | |
| 1444 | void set_bh_page(struct buffer_head *bh, |
| 1445 | struct page *page, unsigned long offset) |
| 1446 | { |
| 1447 | bh->b_page = page; |
Eric Sesterhenn | e827f92 | 2006-03-26 18:24:46 +0200 | [diff] [blame] | 1448 | BUG_ON(offset >= PAGE_SIZE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1449 | if (PageHighMem(page)) |
| 1450 | /* |
| 1451 | * This catches illegal uses and preserves the offset: |
| 1452 | */ |
| 1453 | bh->b_data = (char *)(0 + offset); |
| 1454 | else |
| 1455 | bh->b_data = page_address(page) + offset; |
| 1456 | } |
| 1457 | EXPORT_SYMBOL(set_bh_page); |
| 1458 | |
| 1459 | /* |
| 1460 | * Called when truncating a buffer on a page completely. |
| 1461 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1462 | static void discard_buffer(struct buffer_head * bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1463 | { |
| 1464 | lock_buffer(bh); |
| 1465 | clear_buffer_dirty(bh); |
| 1466 | bh->b_bdev = NULL; |
| 1467 | clear_buffer_mapped(bh); |
| 1468 | clear_buffer_req(bh); |
| 1469 | clear_buffer_new(bh); |
| 1470 | clear_buffer_delay(bh); |
David Chinner | 33a266d | 2007-02-12 00:51:41 -0800 | [diff] [blame] | 1471 | clear_buffer_unwritten(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | unlock_buffer(bh); |
| 1473 | } |
| 1474 | |
| 1475 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1476 | * block_invalidatepage - invalidate part of all of a buffer-backed page |
| 1477 | * |
| 1478 | * @page: the page which is affected |
| 1479 | * @offset: the index of the truncation point |
| 1480 | * |
| 1481 | * block_invalidatepage() is called when all or part of the page has become |
| 1482 | * invalidatedby a truncate operation. |
| 1483 | * |
| 1484 | * block_invalidatepage() does not have to release all buffers, but it must |
| 1485 | * ensure that no dirty buffer is left outside @offset and that no I/O |
| 1486 | * is underway against any of the blocks which are outside the truncation |
| 1487 | * point. Because the caller is about to free (and possibly reuse) those |
| 1488 | * blocks on-disk. |
| 1489 | */ |
NeilBrown | 2ff28e2 | 2006-03-26 01:37:18 -0800 | [diff] [blame] | 1490 | void block_invalidatepage(struct page *page, unsigned long offset) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1491 | { |
| 1492 | struct buffer_head *head, *bh, *next; |
| 1493 | unsigned int curr_off = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1494 | |
| 1495 | BUG_ON(!PageLocked(page)); |
| 1496 | if (!page_has_buffers(page)) |
| 1497 | goto out; |
| 1498 | |
| 1499 | head = page_buffers(page); |
| 1500 | bh = head; |
| 1501 | do { |
| 1502 | unsigned int next_off = curr_off + bh->b_size; |
| 1503 | next = bh->b_this_page; |
| 1504 | |
| 1505 | /* |
| 1506 | * is this block fully invalidated? |
| 1507 | */ |
| 1508 | if (offset <= curr_off) |
| 1509 | discard_buffer(bh); |
| 1510 | curr_off = next_off; |
| 1511 | bh = next; |
| 1512 | } while (bh != head); |
| 1513 | |
| 1514 | /* |
| 1515 | * We release buffers only if the entire page is being invalidated. |
| 1516 | * The get_block cached value has been unconditionally invalidated, |
| 1517 | * so real IO is not possible anymore. |
| 1518 | */ |
| 1519 | if (offset == 0) |
NeilBrown | 2ff28e2 | 2006-03-26 01:37:18 -0800 | [diff] [blame] | 1520 | try_to_release_page(page, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1521 | out: |
NeilBrown | 2ff28e2 | 2006-03-26 01:37:18 -0800 | [diff] [blame] | 1522 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1523 | } |
| 1524 | EXPORT_SYMBOL(block_invalidatepage); |
| 1525 | |
| 1526 | /* |
| 1527 | * We attach and possibly dirty the buffers atomically wrt |
| 1528 | * __set_page_dirty_buffers() via private_lock. try_to_free_buffers |
| 1529 | * is already excluded via the page lock. |
| 1530 | */ |
| 1531 | void create_empty_buffers(struct page *page, |
| 1532 | unsigned long blocksize, unsigned long b_state) |
| 1533 | { |
| 1534 | struct buffer_head *bh, *head, *tail; |
| 1535 | |
| 1536 | head = alloc_page_buffers(page, blocksize, 1); |
| 1537 | bh = head; |
| 1538 | do { |
| 1539 | bh->b_state |= b_state; |
| 1540 | tail = bh; |
| 1541 | bh = bh->b_this_page; |
| 1542 | } while (bh); |
| 1543 | tail->b_this_page = head; |
| 1544 | |
| 1545 | spin_lock(&page->mapping->private_lock); |
| 1546 | if (PageUptodate(page) || PageDirty(page)) { |
| 1547 | bh = head; |
| 1548 | do { |
| 1549 | if (PageDirty(page)) |
| 1550 | set_buffer_dirty(bh); |
| 1551 | if (PageUptodate(page)) |
| 1552 | set_buffer_uptodate(bh); |
| 1553 | bh = bh->b_this_page; |
| 1554 | } while (bh != head); |
| 1555 | } |
| 1556 | attach_page_buffers(page, head); |
| 1557 | spin_unlock(&page->mapping->private_lock); |
| 1558 | } |
| 1559 | EXPORT_SYMBOL(create_empty_buffers); |
| 1560 | |
| 1561 | /* |
| 1562 | * We are taking a block for data and we don't want any output from any |
| 1563 | * buffer-cache aliases starting from return from that function and |
| 1564 | * until the moment when something will explicitly mark the buffer |
| 1565 | * dirty (hopefully that will not happen until we will free that block ;-) |
| 1566 | * We don't even need to mark it not-uptodate - nobody can expect |
| 1567 | * anything from a newly allocated buffer anyway. We used to used |
| 1568 | * unmap_buffer() for such invalidation, but that was wrong. We definitely |
| 1569 | * don't want to mark the alias unmapped, for example - it would confuse |
| 1570 | * anyone who might pick it with bread() afterwards... |
| 1571 | * |
| 1572 | * Also.. Note that bforget() doesn't lock the buffer. So there can |
| 1573 | * be writeout I/O going on against recently-freed buffers. We don't |
| 1574 | * wait on that I/O in bforget() - it's more efficient to wait on the I/O |
| 1575 | * only if we really need to. That happens here. |
| 1576 | */ |
| 1577 | void unmap_underlying_metadata(struct block_device *bdev, sector_t block) |
| 1578 | { |
| 1579 | struct buffer_head *old_bh; |
| 1580 | |
| 1581 | might_sleep(); |
| 1582 | |
Coywolf Qi Hunt | 385fd4c | 2005-11-07 00:59:39 -0800 | [diff] [blame] | 1583 | old_bh = __find_get_block_slow(bdev, block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1584 | if (old_bh) { |
| 1585 | clear_buffer_dirty(old_bh); |
| 1586 | wait_on_buffer(old_bh); |
| 1587 | clear_buffer_req(old_bh); |
| 1588 | __brelse(old_bh); |
| 1589 | } |
| 1590 | } |
| 1591 | EXPORT_SYMBOL(unmap_underlying_metadata); |
| 1592 | |
| 1593 | /* |
| 1594 | * NOTE! All mapped/uptodate combinations are valid: |
| 1595 | * |
| 1596 | * Mapped Uptodate Meaning |
| 1597 | * |
| 1598 | * No No "unknown" - must do get_block() |
| 1599 | * No Yes "hole" - zero-filled |
| 1600 | * Yes No "allocated" - allocated on disk, not read in |
| 1601 | * Yes Yes "valid" - allocated and up-to-date in memory. |
| 1602 | * |
| 1603 | * "Dirty" is valid only with the last case (mapped+uptodate). |
| 1604 | */ |
| 1605 | |
| 1606 | /* |
| 1607 | * While block_write_full_page is writing back the dirty buffers under |
| 1608 | * the page lock, whoever dirtied the buffers may decide to clean them |
| 1609 | * again at any time. We handle that by only looking at the buffer |
| 1610 | * state inside lock_buffer(). |
| 1611 | * |
| 1612 | * If block_write_full_page() is called for regular writeback |
| 1613 | * (wbc->sync_mode == WB_SYNC_NONE) then it will redirty a page which has a |
| 1614 | * locked buffer. This only can happen if someone has written the buffer |
| 1615 | * directly, with submit_bh(). At the address_space level PageWriteback |
| 1616 | * prevents this contention from occurring. |
Theodore Ts'o | 6e34eedd | 2009-04-07 18:12:43 -0400 | [diff] [blame] | 1617 | * |
| 1618 | * If block_write_full_page() is called with wbc->sync_mode == |
| 1619 | * WB_SYNC_ALL, the writes are posted using WRITE_SYNC_PLUG; this |
| 1620 | * causes the writes to be flagged as synchronous writes, but the |
| 1621 | * block device queue will NOT be unplugged, since usually many pages |
| 1622 | * will be pushed to the out before the higher-level caller actually |
| 1623 | * waits for the writes to be completed. The various wait functions, |
| 1624 | * such as wait_on_writeback_range() will ultimately call sync_page() |
| 1625 | * which will ultimately call blk_run_backing_dev(), which will end up |
| 1626 | * unplugging the device queue. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1627 | */ |
| 1628 | static int __block_write_full_page(struct inode *inode, struct page *page, |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 1629 | get_block_t *get_block, struct writeback_control *wbc, |
| 1630 | bh_end_io_t *handler) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1631 | { |
| 1632 | int err; |
| 1633 | sector_t block; |
| 1634 | sector_t last_block; |
Andrew Morton | f0fbd5f | 2005-05-05 16:15:48 -0700 | [diff] [blame] | 1635 | struct buffer_head *bh, *head; |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1636 | const unsigned blocksize = 1 << inode->i_blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1637 | int nr_underway = 0; |
Theodore Ts'o | 6e34eedd | 2009-04-07 18:12:43 -0400 | [diff] [blame] | 1638 | int write_op = (wbc->sync_mode == WB_SYNC_ALL ? |
| 1639 | WRITE_SYNC_PLUG : WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1640 | |
| 1641 | BUG_ON(!PageLocked(page)); |
| 1642 | |
| 1643 | last_block = (i_size_read(inode) - 1) >> inode->i_blkbits; |
| 1644 | |
| 1645 | if (!page_has_buffers(page)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1646 | create_empty_buffers(page, blocksize, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1647 | (1 << BH_Dirty)|(1 << BH_Uptodate)); |
| 1648 | } |
| 1649 | |
| 1650 | /* |
| 1651 | * Be very careful. We have no exclusion from __set_page_dirty_buffers |
| 1652 | * here, and the (potentially unmapped) buffers may become dirty at |
| 1653 | * any time. If a buffer becomes dirty here after we've inspected it |
| 1654 | * then we just miss that fact, and the page stays dirty. |
| 1655 | * |
| 1656 | * Buffers outside i_size may be dirtied by __set_page_dirty_buffers; |
| 1657 | * handle that here by just cleaning them. |
| 1658 | */ |
| 1659 | |
Andrew Morton | 54b21a7 | 2006-01-08 01:03:05 -0800 | [diff] [blame] | 1660 | block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1661 | head = page_buffers(page); |
| 1662 | bh = head; |
| 1663 | |
| 1664 | /* |
| 1665 | * Get all the dirty buffers mapped to disk addresses and |
| 1666 | * handle any aliases from the underlying blockdev's mapping. |
| 1667 | */ |
| 1668 | do { |
| 1669 | if (block > last_block) { |
| 1670 | /* |
| 1671 | * mapped buffers outside i_size will occur, because |
| 1672 | * this page can be outside i_size when there is a |
| 1673 | * truncate in progress. |
| 1674 | */ |
| 1675 | /* |
| 1676 | * The buffer was zeroed by block_write_full_page() |
| 1677 | */ |
| 1678 | clear_buffer_dirty(bh); |
| 1679 | set_buffer_uptodate(bh); |
Alex Tomas | 29a814d | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 1680 | } else if ((!buffer_mapped(bh) || buffer_delay(bh)) && |
| 1681 | buffer_dirty(bh)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1682 | WARN_ON(bh->b_size != blocksize); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1683 | err = get_block(inode, block, bh, 1); |
| 1684 | if (err) |
| 1685 | goto recover; |
Alex Tomas | 29a814d | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 1686 | clear_buffer_delay(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1687 | if (buffer_new(bh)) { |
| 1688 | /* blockdev mappings never come here */ |
| 1689 | clear_buffer_new(bh); |
| 1690 | unmap_underlying_metadata(bh->b_bdev, |
| 1691 | bh->b_blocknr); |
| 1692 | } |
| 1693 | } |
| 1694 | bh = bh->b_this_page; |
| 1695 | block++; |
| 1696 | } while (bh != head); |
| 1697 | |
| 1698 | do { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1699 | if (!buffer_mapped(bh)) |
| 1700 | continue; |
| 1701 | /* |
| 1702 | * If it's a fully non-blocking write attempt and we cannot |
| 1703 | * lock the buffer then redirty the page. Note that this can |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 1704 | * potentially cause a busy-wait loop from writeback threads |
| 1705 | * and kswapd activity, but those code paths have their own |
| 1706 | * higher-level throttling. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1707 | */ |
| 1708 | if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { |
| 1709 | lock_buffer(bh); |
Nick Piggin | ca5de40 | 2008-08-02 12:02:13 +0200 | [diff] [blame] | 1710 | } else if (!trylock_buffer(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1711 | redirty_page_for_writepage(wbc, page); |
| 1712 | continue; |
| 1713 | } |
| 1714 | if (test_clear_buffer_dirty(bh)) { |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 1715 | mark_buffer_async_write_endio(bh, handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1716 | } else { |
| 1717 | unlock_buffer(bh); |
| 1718 | } |
| 1719 | } while ((bh = bh->b_this_page) != head); |
| 1720 | |
| 1721 | /* |
| 1722 | * The page and its buffers are protected by PageWriteback(), so we can |
| 1723 | * drop the bh refcounts early. |
| 1724 | */ |
| 1725 | BUG_ON(PageWriteback(page)); |
| 1726 | set_page_writeback(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1727 | |
| 1728 | do { |
| 1729 | struct buffer_head *next = bh->b_this_page; |
| 1730 | if (buffer_async_write(bh)) { |
Theodore Ts'o | a64c861 | 2009-03-27 22:14:10 -0400 | [diff] [blame] | 1731 | submit_bh(write_op, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1732 | nr_underway++; |
| 1733 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1734 | bh = next; |
| 1735 | } while (bh != head); |
Andrew Morton | 05937ba | 2005-05-05 16:15:47 -0700 | [diff] [blame] | 1736 | unlock_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1737 | |
| 1738 | err = 0; |
| 1739 | done: |
| 1740 | if (nr_underway == 0) { |
| 1741 | /* |
| 1742 | * The page was marked dirty, but the buffers were |
| 1743 | * clean. Someone wrote them back by hand with |
| 1744 | * ll_rw_block/submit_bh. A rare case. |
| 1745 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1746 | end_page_writeback(page); |
Nick Piggin | 3d67f2d | 2007-05-06 14:49:05 -0700 | [diff] [blame] | 1747 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1748 | /* |
| 1749 | * The page and buffer_heads can be released at any time from |
| 1750 | * here on. |
| 1751 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1752 | } |
| 1753 | return err; |
| 1754 | |
| 1755 | recover: |
| 1756 | /* |
| 1757 | * ENOSPC, or some other error. We may already have added some |
| 1758 | * blocks to the file, so we need to write these out to avoid |
| 1759 | * exposing stale data. |
| 1760 | * The page is currently locked and not marked for writeback |
| 1761 | */ |
| 1762 | bh = head; |
| 1763 | /* Recovery: lock and submit the mapped buffers */ |
| 1764 | do { |
Alex Tomas | 29a814d | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 1765 | if (buffer_mapped(bh) && buffer_dirty(bh) && |
| 1766 | !buffer_delay(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1767 | lock_buffer(bh); |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 1768 | mark_buffer_async_write_endio(bh, handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1769 | } else { |
| 1770 | /* |
| 1771 | * The buffer may have been set dirty during |
| 1772 | * attachment to a dirty page. |
| 1773 | */ |
| 1774 | clear_buffer_dirty(bh); |
| 1775 | } |
| 1776 | } while ((bh = bh->b_this_page) != head); |
| 1777 | SetPageError(page); |
| 1778 | BUG_ON(PageWriteback(page)); |
Andrew Morton | 7e4c369 | 2007-05-08 00:23:27 -0700 | [diff] [blame] | 1779 | mapping_set_error(page->mapping, err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1780 | set_page_writeback(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1781 | do { |
| 1782 | struct buffer_head *next = bh->b_this_page; |
| 1783 | if (buffer_async_write(bh)) { |
| 1784 | clear_buffer_dirty(bh); |
Theodore Ts'o | a64c861 | 2009-03-27 22:14:10 -0400 | [diff] [blame] | 1785 | submit_bh(write_op, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1786 | nr_underway++; |
| 1787 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1788 | bh = next; |
| 1789 | } while (bh != head); |
Nick Piggin | ffda9d3 | 2007-02-20 13:57:54 -0800 | [diff] [blame] | 1790 | unlock_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1791 | goto done; |
| 1792 | } |
| 1793 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1794 | /* |
| 1795 | * If a page has any new buffers, zero them out here, and mark them uptodate |
| 1796 | * and dirty so they'll be written out (in order to prevent uninitialised |
| 1797 | * block data from leaking). And clear the new bit. |
| 1798 | */ |
| 1799 | void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) |
| 1800 | { |
| 1801 | unsigned int block_start, block_end; |
| 1802 | struct buffer_head *head, *bh; |
| 1803 | |
| 1804 | BUG_ON(!PageLocked(page)); |
| 1805 | if (!page_has_buffers(page)) |
| 1806 | return; |
| 1807 | |
| 1808 | bh = head = page_buffers(page); |
| 1809 | block_start = 0; |
| 1810 | do { |
| 1811 | block_end = block_start + bh->b_size; |
| 1812 | |
| 1813 | if (buffer_new(bh)) { |
| 1814 | if (block_end > from && block_start < to) { |
| 1815 | if (!PageUptodate(page)) { |
| 1816 | unsigned start, size; |
| 1817 | |
| 1818 | start = max(from, block_start); |
| 1819 | size = min(to, block_end) - start; |
| 1820 | |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 1821 | zero_user(page, start, size); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1822 | set_buffer_uptodate(bh); |
| 1823 | } |
| 1824 | |
| 1825 | clear_buffer_new(bh); |
| 1826 | mark_buffer_dirty(bh); |
| 1827 | } |
| 1828 | } |
| 1829 | |
| 1830 | block_start = block_end; |
| 1831 | bh = bh->b_this_page; |
| 1832 | } while (bh != head); |
| 1833 | } |
| 1834 | EXPORT_SYMBOL(page_zero_new_buffers); |
| 1835 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1836 | static int __block_prepare_write(struct inode *inode, struct page *page, |
| 1837 | unsigned from, unsigned to, get_block_t *get_block) |
| 1838 | { |
| 1839 | unsigned block_start, block_end; |
| 1840 | sector_t block; |
| 1841 | int err = 0; |
| 1842 | unsigned blocksize, bbits; |
| 1843 | struct buffer_head *bh, *head, *wait[2], **wait_bh=wait; |
| 1844 | |
| 1845 | BUG_ON(!PageLocked(page)); |
| 1846 | BUG_ON(from > PAGE_CACHE_SIZE); |
| 1847 | BUG_ON(to > PAGE_CACHE_SIZE); |
| 1848 | BUG_ON(from > to); |
| 1849 | |
| 1850 | blocksize = 1 << inode->i_blkbits; |
| 1851 | if (!page_has_buffers(page)) |
| 1852 | create_empty_buffers(page, blocksize, 0); |
| 1853 | head = page_buffers(page); |
| 1854 | |
| 1855 | bbits = inode->i_blkbits; |
| 1856 | block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); |
| 1857 | |
| 1858 | for(bh = head, block_start = 0; bh != head || !block_start; |
| 1859 | block++, block_start=block_end, bh = bh->b_this_page) { |
| 1860 | block_end = block_start + blocksize; |
| 1861 | if (block_end <= from || block_start >= to) { |
| 1862 | if (PageUptodate(page)) { |
| 1863 | if (!buffer_uptodate(bh)) |
| 1864 | set_buffer_uptodate(bh); |
| 1865 | } |
| 1866 | continue; |
| 1867 | } |
| 1868 | if (buffer_new(bh)) |
| 1869 | clear_buffer_new(bh); |
| 1870 | if (!buffer_mapped(bh)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 1871 | WARN_ON(bh->b_size != blocksize); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1872 | err = get_block(inode, block, bh, 1); |
| 1873 | if (err) |
Nick Piggin | f3ddbdc | 2005-05-05 16:15:45 -0700 | [diff] [blame] | 1874 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1875 | if (buffer_new(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1876 | unmap_underlying_metadata(bh->b_bdev, |
| 1877 | bh->b_blocknr); |
| 1878 | if (PageUptodate(page)) { |
Nick Piggin | 637aff4 | 2007-10-16 01:25:00 -0700 | [diff] [blame] | 1879 | clear_buffer_new(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1880 | set_buffer_uptodate(bh); |
Nick Piggin | 637aff4 | 2007-10-16 01:25:00 -0700 | [diff] [blame] | 1881 | mark_buffer_dirty(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1882 | continue; |
| 1883 | } |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 1884 | if (block_end > to || block_start < from) |
| 1885 | zero_user_segments(page, |
| 1886 | to, block_end, |
| 1887 | block_start, from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1888 | continue; |
| 1889 | } |
| 1890 | } |
| 1891 | if (PageUptodate(page)) { |
| 1892 | if (!buffer_uptodate(bh)) |
| 1893 | set_buffer_uptodate(bh); |
| 1894 | continue; |
| 1895 | } |
| 1896 | if (!buffer_uptodate(bh) && !buffer_delay(bh) && |
David Chinner | 33a266d | 2007-02-12 00:51:41 -0800 | [diff] [blame] | 1897 | !buffer_unwritten(bh) && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1898 | (block_start < from || block_end > to)) { |
| 1899 | ll_rw_block(READ, 1, &bh); |
| 1900 | *wait_bh++=bh; |
| 1901 | } |
| 1902 | } |
| 1903 | /* |
| 1904 | * If we issued read requests - let them complete. |
| 1905 | */ |
| 1906 | while(wait_bh > wait) { |
| 1907 | wait_on_buffer(*--wait_bh); |
| 1908 | if (!buffer_uptodate(*wait_bh)) |
Nick Piggin | f3ddbdc | 2005-05-05 16:15:45 -0700 | [diff] [blame] | 1909 | err = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1910 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1911 | if (unlikely(err)) |
| 1912 | page_zero_new_buffers(page, from, to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1913 | return err; |
| 1914 | } |
| 1915 | |
| 1916 | static int __block_commit_write(struct inode *inode, struct page *page, |
| 1917 | unsigned from, unsigned to) |
| 1918 | { |
| 1919 | unsigned block_start, block_end; |
| 1920 | int partial = 0; |
| 1921 | unsigned blocksize; |
| 1922 | struct buffer_head *bh, *head; |
| 1923 | |
| 1924 | blocksize = 1 << inode->i_blkbits; |
| 1925 | |
| 1926 | for(bh = head = page_buffers(page), block_start = 0; |
| 1927 | bh != head || !block_start; |
| 1928 | block_start=block_end, bh = bh->b_this_page) { |
| 1929 | block_end = block_start + blocksize; |
| 1930 | if (block_end <= from || block_start >= to) { |
| 1931 | if (!buffer_uptodate(bh)) |
| 1932 | partial = 1; |
| 1933 | } else { |
| 1934 | set_buffer_uptodate(bh); |
| 1935 | mark_buffer_dirty(bh); |
| 1936 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1937 | clear_buffer_new(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1938 | } |
| 1939 | |
| 1940 | /* |
| 1941 | * If this is a partial write which happened to make all buffers |
| 1942 | * uptodate then we can optimize away a bogus readpage() for |
| 1943 | * the next read(). Here we 'discover' whether the page went |
| 1944 | * uptodate as a result of this (potentially partial) write. |
| 1945 | */ |
| 1946 | if (!partial) |
| 1947 | SetPageUptodate(page); |
| 1948 | return 0; |
| 1949 | } |
| 1950 | |
| 1951 | /* |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 1952 | * Filesystems implementing the new truncate sequence should use the |
| 1953 | * _newtrunc postfix variant which won't incorrectly call vmtruncate. |
| 1954 | * The filesystem needs to handle block truncation upon failure. |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1955 | */ |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 1956 | int block_write_begin_newtrunc(struct file *file, struct address_space *mapping, |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1957 | loff_t pos, unsigned len, unsigned flags, |
| 1958 | struct page **pagep, void **fsdata, |
| 1959 | get_block_t *get_block) |
| 1960 | { |
| 1961 | struct inode *inode = mapping->host; |
| 1962 | int status = 0; |
| 1963 | struct page *page; |
| 1964 | pgoff_t index; |
| 1965 | unsigned start, end; |
| 1966 | int ownpage = 0; |
| 1967 | |
| 1968 | index = pos >> PAGE_CACHE_SHIFT; |
| 1969 | start = pos & (PAGE_CACHE_SIZE - 1); |
| 1970 | end = start + len; |
| 1971 | |
| 1972 | page = *pagep; |
| 1973 | if (page == NULL) { |
| 1974 | ownpage = 1; |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 1975 | page = grab_cache_page_write_begin(mapping, index, flags); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1976 | if (!page) { |
| 1977 | status = -ENOMEM; |
| 1978 | goto out; |
| 1979 | } |
| 1980 | *pagep = page; |
| 1981 | } else |
| 1982 | BUG_ON(!PageLocked(page)); |
| 1983 | |
| 1984 | status = __block_prepare_write(inode, page, start, end, get_block); |
| 1985 | if (unlikely(status)) { |
| 1986 | ClearPageUptodate(page); |
| 1987 | |
| 1988 | if (ownpage) { |
| 1989 | unlock_page(page); |
| 1990 | page_cache_release(page); |
| 1991 | *pagep = NULL; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1992 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1993 | } |
| 1994 | |
| 1995 | out: |
| 1996 | return status; |
| 1997 | } |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 1998 | EXPORT_SYMBOL(block_write_begin_newtrunc); |
| 1999 | |
| 2000 | /* |
| 2001 | * block_write_begin takes care of the basic task of block allocation and |
| 2002 | * bringing partial write blocks uptodate first. |
| 2003 | * |
| 2004 | * If *pagep is not NULL, then block_write_begin uses the locked page |
| 2005 | * at *pagep rather than allocating its own. In this case, the page will |
| 2006 | * not be unlocked or deallocated on failure. |
| 2007 | */ |
| 2008 | int block_write_begin(struct file *file, struct address_space *mapping, |
| 2009 | loff_t pos, unsigned len, unsigned flags, |
| 2010 | struct page **pagep, void **fsdata, |
| 2011 | get_block_t *get_block) |
| 2012 | { |
| 2013 | int ret; |
| 2014 | |
| 2015 | ret = block_write_begin_newtrunc(file, mapping, pos, len, flags, |
| 2016 | pagep, fsdata, get_block); |
| 2017 | |
| 2018 | /* |
| 2019 | * prepare_write() may have instantiated a few blocks |
| 2020 | * outside i_size. Trim these off again. Don't need |
| 2021 | * i_size_read because we hold i_mutex. |
| 2022 | * |
| 2023 | * Filesystems which pass down their own page also cannot |
| 2024 | * call into vmtruncate here because it would lead to lock |
| 2025 | * inversion problems (*pagep is locked). This is a further |
| 2026 | * example of where the old truncate sequence is inadequate. |
| 2027 | */ |
| 2028 | if (unlikely(ret) && *pagep == NULL) { |
| 2029 | loff_t isize = mapping->host->i_size; |
| 2030 | if (pos + len > isize) |
| 2031 | vmtruncate(mapping->host, isize); |
| 2032 | } |
| 2033 | |
| 2034 | return ret; |
| 2035 | } |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2036 | EXPORT_SYMBOL(block_write_begin); |
| 2037 | |
| 2038 | int block_write_end(struct file *file, struct address_space *mapping, |
| 2039 | loff_t pos, unsigned len, unsigned copied, |
| 2040 | struct page *page, void *fsdata) |
| 2041 | { |
| 2042 | struct inode *inode = mapping->host; |
| 2043 | unsigned start; |
| 2044 | |
| 2045 | start = pos & (PAGE_CACHE_SIZE - 1); |
| 2046 | |
| 2047 | if (unlikely(copied < len)) { |
| 2048 | /* |
| 2049 | * The buffers that were written will now be uptodate, so we |
| 2050 | * don't have to worry about a readpage reading them and |
| 2051 | * overwriting a partial write. However if we have encountered |
| 2052 | * a short write and only partially written into a buffer, it |
| 2053 | * will not be marked uptodate, so a readpage might come in and |
| 2054 | * destroy our partial write. |
| 2055 | * |
| 2056 | * Do the simplest thing, and just treat any short write to a |
| 2057 | * non uptodate page as a zero-length write, and force the |
| 2058 | * caller to redo the whole thing. |
| 2059 | */ |
| 2060 | if (!PageUptodate(page)) |
| 2061 | copied = 0; |
| 2062 | |
| 2063 | page_zero_new_buffers(page, start+copied, start+len); |
| 2064 | } |
| 2065 | flush_dcache_page(page); |
| 2066 | |
| 2067 | /* This could be a short (even 0-length) commit */ |
| 2068 | __block_commit_write(inode, page, start, start+copied); |
| 2069 | |
| 2070 | return copied; |
| 2071 | } |
| 2072 | EXPORT_SYMBOL(block_write_end); |
| 2073 | |
| 2074 | int generic_write_end(struct file *file, struct address_space *mapping, |
| 2075 | loff_t pos, unsigned len, unsigned copied, |
| 2076 | struct page *page, void *fsdata) |
| 2077 | { |
| 2078 | struct inode *inode = mapping->host; |
Jan Kara | c7d206b | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 2079 | int i_size_changed = 0; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2080 | |
| 2081 | copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); |
| 2082 | |
| 2083 | /* |
| 2084 | * No need to use i_size_read() here, the i_size |
| 2085 | * cannot change under us because we hold i_mutex. |
| 2086 | * |
| 2087 | * But it's important to update i_size while still holding page lock: |
| 2088 | * page writeout could otherwise come in and zero beyond i_size. |
| 2089 | */ |
| 2090 | if (pos+copied > inode->i_size) { |
| 2091 | i_size_write(inode, pos+copied); |
Jan Kara | c7d206b | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 2092 | i_size_changed = 1; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2093 | } |
| 2094 | |
| 2095 | unlock_page(page); |
| 2096 | page_cache_release(page); |
| 2097 | |
Jan Kara | c7d206b | 2008-07-11 19:27:31 -0400 | [diff] [blame] | 2098 | /* |
| 2099 | * Don't mark the inode dirty under page lock. First, it unnecessarily |
| 2100 | * makes the holding time of page lock longer. Second, it forces lock |
| 2101 | * ordering of page lock and transaction start for journaling |
| 2102 | * filesystems. |
| 2103 | */ |
| 2104 | if (i_size_changed) |
| 2105 | mark_inode_dirty(inode); |
| 2106 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2107 | return copied; |
| 2108 | } |
| 2109 | EXPORT_SYMBOL(generic_write_end); |
| 2110 | |
| 2111 | /* |
Hisashi Hifumi | 8ab22b9 | 2008-07-28 15:46:36 -0700 | [diff] [blame] | 2112 | * block_is_partially_uptodate checks whether buffers within a page are |
| 2113 | * uptodate or not. |
| 2114 | * |
| 2115 | * Returns true if all buffers which correspond to a file portion |
| 2116 | * we want to read are uptodate. |
| 2117 | */ |
| 2118 | int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, |
| 2119 | unsigned long from) |
| 2120 | { |
| 2121 | struct inode *inode = page->mapping->host; |
| 2122 | unsigned block_start, block_end, blocksize; |
| 2123 | unsigned to; |
| 2124 | struct buffer_head *bh, *head; |
| 2125 | int ret = 1; |
| 2126 | |
| 2127 | if (!page_has_buffers(page)) |
| 2128 | return 0; |
| 2129 | |
| 2130 | blocksize = 1 << inode->i_blkbits; |
| 2131 | to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count); |
| 2132 | to = from + to; |
| 2133 | if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize) |
| 2134 | return 0; |
| 2135 | |
| 2136 | head = page_buffers(page); |
| 2137 | bh = head; |
| 2138 | block_start = 0; |
| 2139 | do { |
| 2140 | block_end = block_start + blocksize; |
| 2141 | if (block_end > from && block_start < to) { |
| 2142 | if (!buffer_uptodate(bh)) { |
| 2143 | ret = 0; |
| 2144 | break; |
| 2145 | } |
| 2146 | if (block_end >= to) |
| 2147 | break; |
| 2148 | } |
| 2149 | block_start = block_end; |
| 2150 | bh = bh->b_this_page; |
| 2151 | } while (bh != head); |
| 2152 | |
| 2153 | return ret; |
| 2154 | } |
| 2155 | EXPORT_SYMBOL(block_is_partially_uptodate); |
| 2156 | |
| 2157 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2158 | * Generic "read page" function for block devices that have the normal |
| 2159 | * get_block functionality. This is most of the block device filesystems. |
| 2160 | * Reads the page asynchronously --- the unlock_buffer() and |
| 2161 | * set/clear_buffer_uptodate() functions propagate buffer state into the |
| 2162 | * page struct once IO has completed. |
| 2163 | */ |
| 2164 | int block_read_full_page(struct page *page, get_block_t *get_block) |
| 2165 | { |
| 2166 | struct inode *inode = page->mapping->host; |
| 2167 | sector_t iblock, lblock; |
| 2168 | struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; |
| 2169 | unsigned int blocksize; |
| 2170 | int nr, i; |
| 2171 | int fully_mapped = 1; |
| 2172 | |
Matt Mackall | cd7619d | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 2173 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2174 | blocksize = 1 << inode->i_blkbits; |
| 2175 | if (!page_has_buffers(page)) |
| 2176 | create_empty_buffers(page, blocksize, 0); |
| 2177 | head = page_buffers(page); |
| 2178 | |
| 2179 | iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
| 2180 | lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits; |
| 2181 | bh = head; |
| 2182 | nr = 0; |
| 2183 | i = 0; |
| 2184 | |
| 2185 | do { |
| 2186 | if (buffer_uptodate(bh)) |
| 2187 | continue; |
| 2188 | |
| 2189 | if (!buffer_mapped(bh)) { |
Andrew Morton | c64610b | 2005-05-16 21:53:49 -0700 | [diff] [blame] | 2190 | int err = 0; |
| 2191 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2192 | fully_mapped = 0; |
| 2193 | if (iblock < lblock) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 2194 | WARN_ON(bh->b_size != blocksize); |
Andrew Morton | c64610b | 2005-05-16 21:53:49 -0700 | [diff] [blame] | 2195 | err = get_block(inode, iblock, bh, 0); |
| 2196 | if (err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2197 | SetPageError(page); |
| 2198 | } |
| 2199 | if (!buffer_mapped(bh)) { |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2200 | zero_user(page, i * blocksize, blocksize); |
Andrew Morton | c64610b | 2005-05-16 21:53:49 -0700 | [diff] [blame] | 2201 | if (!err) |
| 2202 | set_buffer_uptodate(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2203 | continue; |
| 2204 | } |
| 2205 | /* |
| 2206 | * get_block() might have updated the buffer |
| 2207 | * synchronously |
| 2208 | */ |
| 2209 | if (buffer_uptodate(bh)) |
| 2210 | continue; |
| 2211 | } |
| 2212 | arr[nr++] = bh; |
| 2213 | } while (i++, iblock++, (bh = bh->b_this_page) != head); |
| 2214 | |
| 2215 | if (fully_mapped) |
| 2216 | SetPageMappedToDisk(page); |
| 2217 | |
| 2218 | if (!nr) { |
| 2219 | /* |
| 2220 | * All buffers are uptodate - we can set the page uptodate |
| 2221 | * as well. But not if get_block() returned an error. |
| 2222 | */ |
| 2223 | if (!PageError(page)) |
| 2224 | SetPageUptodate(page); |
| 2225 | unlock_page(page); |
| 2226 | return 0; |
| 2227 | } |
| 2228 | |
| 2229 | /* Stage two: lock the buffers */ |
| 2230 | for (i = 0; i < nr; i++) { |
| 2231 | bh = arr[i]; |
| 2232 | lock_buffer(bh); |
| 2233 | mark_buffer_async_read(bh); |
| 2234 | } |
| 2235 | |
| 2236 | /* |
| 2237 | * Stage 3: start the IO. Check for uptodateness |
| 2238 | * inside the buffer lock in case another process reading |
| 2239 | * the underlying blockdev brought it uptodate (the sct fix). |
| 2240 | */ |
| 2241 | for (i = 0; i < nr; i++) { |
| 2242 | bh = arr[i]; |
| 2243 | if (buffer_uptodate(bh)) |
| 2244 | end_buffer_async_read(bh, 1); |
| 2245 | else |
| 2246 | submit_bh(READ, bh); |
| 2247 | } |
| 2248 | return 0; |
| 2249 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2250 | EXPORT_SYMBOL(block_read_full_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2251 | |
| 2252 | /* utility function for filesystems that need to do work on expanding |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2253 | * truncates. Uses filesystem pagecache writes to allow the filesystem to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2254 | * deal with the hole. |
| 2255 | */ |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2256 | int generic_cont_expand_simple(struct inode *inode, loff_t size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2257 | { |
| 2258 | struct address_space *mapping = inode->i_mapping; |
| 2259 | struct page *page; |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2260 | void *fsdata; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2261 | int err; |
| 2262 | |
npiggin@suse.de | c08d3b0 | 2009-08-21 02:35:06 +1000 | [diff] [blame] | 2263 | err = inode_newsize_ok(inode, size); |
| 2264 | if (err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2265 | goto out; |
| 2266 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2267 | err = pagecache_write_begin(NULL, mapping, size, 0, |
| 2268 | AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND, |
| 2269 | &page, &fsdata); |
| 2270 | if (err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2271 | goto out; |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2272 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2273 | err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata); |
| 2274 | BUG_ON(err > 0); |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2275 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2276 | out: |
| 2277 | return err; |
| 2278 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2279 | EXPORT_SYMBOL(generic_cont_expand_simple); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2280 | |
Adrian Bunk | f1e3af7 | 2008-04-29 00:59:01 -0700 | [diff] [blame] | 2281 | static int cont_expand_zero(struct file *file, struct address_space *mapping, |
| 2282 | loff_t pos, loff_t *bytes) |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2283 | { |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2284 | struct inode *inode = mapping->host; |
| 2285 | unsigned blocksize = 1 << inode->i_blkbits; |
| 2286 | struct page *page; |
| 2287 | void *fsdata; |
| 2288 | pgoff_t index, curidx; |
| 2289 | loff_t curpos; |
| 2290 | unsigned zerofrom, offset, len; |
| 2291 | int err = 0; |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2292 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2293 | index = pos >> PAGE_CACHE_SHIFT; |
| 2294 | offset = pos & ~PAGE_CACHE_MASK; |
| 2295 | |
| 2296 | while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) { |
| 2297 | zerofrom = curpos & ~PAGE_CACHE_MASK; |
| 2298 | if (zerofrom & (blocksize-1)) { |
| 2299 | *bytes |= (blocksize-1); |
| 2300 | (*bytes)++; |
| 2301 | } |
| 2302 | len = PAGE_CACHE_SIZE - zerofrom; |
| 2303 | |
| 2304 | err = pagecache_write_begin(file, mapping, curpos, len, |
| 2305 | AOP_FLAG_UNINTERRUPTIBLE, |
| 2306 | &page, &fsdata); |
| 2307 | if (err) |
| 2308 | goto out; |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2309 | zero_user(page, zerofrom, len); |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2310 | err = pagecache_write_end(file, mapping, curpos, len, len, |
| 2311 | page, fsdata); |
| 2312 | if (err < 0) |
| 2313 | goto out; |
| 2314 | BUG_ON(err != len); |
| 2315 | err = 0; |
OGAWA Hirofumi | 061e974 | 2008-04-28 02:16:28 -0700 | [diff] [blame] | 2316 | |
| 2317 | balance_dirty_pages_ratelimited(mapping); |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2318 | } |
| 2319 | |
| 2320 | /* page covers the boundary, find the boundary offset */ |
| 2321 | if (index == curidx) { |
| 2322 | zerofrom = curpos & ~PAGE_CACHE_MASK; |
| 2323 | /* if we will expand the thing last block will be filled */ |
| 2324 | if (offset <= zerofrom) { |
| 2325 | goto out; |
| 2326 | } |
| 2327 | if (zerofrom & (blocksize-1)) { |
| 2328 | *bytes |= (blocksize-1); |
| 2329 | (*bytes)++; |
| 2330 | } |
| 2331 | len = offset - zerofrom; |
| 2332 | |
| 2333 | err = pagecache_write_begin(file, mapping, curpos, len, |
| 2334 | AOP_FLAG_UNINTERRUPTIBLE, |
| 2335 | &page, &fsdata); |
| 2336 | if (err) |
| 2337 | goto out; |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2338 | zero_user(page, zerofrom, len); |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2339 | err = pagecache_write_end(file, mapping, curpos, len, len, |
| 2340 | page, fsdata); |
| 2341 | if (err < 0) |
| 2342 | goto out; |
| 2343 | BUG_ON(err != len); |
| 2344 | err = 0; |
| 2345 | } |
| 2346 | out: |
| 2347 | return err; |
OGAWA Hirofumi | 05eb0b5 | 2006-01-08 01:02:13 -0800 | [diff] [blame] | 2348 | } |
| 2349 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2350 | /* |
| 2351 | * For moronic filesystems that do not allow holes in file. |
| 2352 | * We may have to extend the file. |
| 2353 | */ |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2354 | int cont_write_begin_newtrunc(struct file *file, struct address_space *mapping, |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2355 | loff_t pos, unsigned len, unsigned flags, |
| 2356 | struct page **pagep, void **fsdata, |
| 2357 | get_block_t *get_block, loff_t *bytes) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2358 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2359 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2360 | unsigned blocksize = 1 << inode->i_blkbits; |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2361 | unsigned zerofrom; |
| 2362 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2363 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2364 | err = cont_expand_zero(file, mapping, pos, bytes); |
| 2365 | if (err) |
| 2366 | goto out; |
| 2367 | |
| 2368 | zerofrom = *bytes & ~PAGE_CACHE_MASK; |
| 2369 | if (pos+len > *bytes && zerofrom & (blocksize-1)) { |
| 2370 | *bytes |= (blocksize-1); |
| 2371 | (*bytes)++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2372 | } |
| 2373 | |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2374 | *pagep = NULL; |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2375 | err = block_write_begin_newtrunc(file, mapping, pos, len, |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2376 | flags, pagep, fsdata, get_block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2377 | out: |
Nick Piggin | 89e1078 | 2007-10-16 01:25:07 -0700 | [diff] [blame] | 2378 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2379 | } |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2380 | EXPORT_SYMBOL(cont_write_begin_newtrunc); |
| 2381 | |
| 2382 | int cont_write_begin(struct file *file, struct address_space *mapping, |
| 2383 | loff_t pos, unsigned len, unsigned flags, |
| 2384 | struct page **pagep, void **fsdata, |
| 2385 | get_block_t *get_block, loff_t *bytes) |
| 2386 | { |
| 2387 | int ret; |
| 2388 | |
| 2389 | ret = cont_write_begin_newtrunc(file, mapping, pos, len, flags, |
| 2390 | pagep, fsdata, get_block, bytes); |
| 2391 | if (unlikely(ret)) { |
| 2392 | loff_t isize = mapping->host->i_size; |
| 2393 | if (pos + len > isize) |
| 2394 | vmtruncate(mapping->host, isize); |
| 2395 | } |
| 2396 | |
| 2397 | return ret; |
| 2398 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2399 | EXPORT_SYMBOL(cont_write_begin); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2400 | |
| 2401 | int block_prepare_write(struct page *page, unsigned from, unsigned to, |
| 2402 | get_block_t *get_block) |
| 2403 | { |
| 2404 | struct inode *inode = page->mapping->host; |
| 2405 | int err = __block_prepare_write(inode, page, from, to, get_block); |
| 2406 | if (err) |
| 2407 | ClearPageUptodate(page); |
| 2408 | return err; |
| 2409 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2410 | EXPORT_SYMBOL(block_prepare_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2411 | |
| 2412 | int block_commit_write(struct page *page, unsigned from, unsigned to) |
| 2413 | { |
| 2414 | struct inode *inode = page->mapping->host; |
| 2415 | __block_commit_write(inode,page,from,to); |
| 2416 | return 0; |
| 2417 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2418 | EXPORT_SYMBOL(block_commit_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2419 | |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2420 | /* |
| 2421 | * block_page_mkwrite() is not allowed to change the file size as it gets |
| 2422 | * called from a page fault handler when a page is first dirtied. Hence we must |
| 2423 | * be careful to check for EOF conditions here. We set the page up correctly |
| 2424 | * for a written page which means we get ENOSPC checking when writing into |
| 2425 | * holes and correct delalloc and unwritten extent mapping on filesystems that |
| 2426 | * support these features. |
| 2427 | * |
| 2428 | * We are not allowed to take the i_mutex here so we have to play games to |
| 2429 | * protect against truncate races as the page could now be beyond EOF. Because |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2430 | * truncate writes the inode size before removing pages, once we have the |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2431 | * page lock we can determine safely if the page is beyond EOF. If it is not |
| 2432 | * beyond EOF, then the page is guaranteed safe against truncation until we |
| 2433 | * unlock the page. |
| 2434 | */ |
| 2435 | int |
Nick Piggin | c2ec175 | 2009-03-31 15:23:21 -0700 | [diff] [blame] | 2436 | block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2437 | get_block_t get_block) |
| 2438 | { |
Nick Piggin | c2ec175 | 2009-03-31 15:23:21 -0700 | [diff] [blame] | 2439 | struct page *page = vmf->page; |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2440 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
| 2441 | unsigned long end; |
| 2442 | loff_t size; |
Nick Piggin | 56a76f8 | 2009-03-31 15:23:23 -0700 | [diff] [blame] | 2443 | int ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */ |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2444 | |
| 2445 | lock_page(page); |
| 2446 | size = i_size_read(inode); |
| 2447 | if ((page->mapping != inode->i_mapping) || |
Nick Piggin | 1833633 | 2007-07-20 00:31:45 -0700 | [diff] [blame] | 2448 | (page_offset(page) > size)) { |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2449 | /* page got truncated out from underneath us */ |
Nick Piggin | b827e49 | 2009-04-30 15:08:16 -0700 | [diff] [blame] | 2450 | unlock_page(page); |
| 2451 | goto out; |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2452 | } |
| 2453 | |
| 2454 | /* page is wholly or partially inside EOF */ |
| 2455 | if (((page->index + 1) << PAGE_CACHE_SHIFT) > size) |
| 2456 | end = size & ~PAGE_CACHE_MASK; |
| 2457 | else |
| 2458 | end = PAGE_CACHE_SIZE; |
| 2459 | |
| 2460 | ret = block_prepare_write(page, 0, end, get_block); |
| 2461 | if (!ret) |
| 2462 | ret = block_commit_write(page, 0, end); |
| 2463 | |
Nick Piggin | 56a76f8 | 2009-03-31 15:23:23 -0700 | [diff] [blame] | 2464 | if (unlikely(ret)) { |
Nick Piggin | b827e49 | 2009-04-30 15:08:16 -0700 | [diff] [blame] | 2465 | unlock_page(page); |
Nick Piggin | 56a76f8 | 2009-03-31 15:23:23 -0700 | [diff] [blame] | 2466 | if (ret == -ENOMEM) |
| 2467 | ret = VM_FAULT_OOM; |
| 2468 | else /* -ENOSPC, -EIO, etc */ |
| 2469 | ret = VM_FAULT_SIGBUS; |
Nick Piggin | b827e49 | 2009-04-30 15:08:16 -0700 | [diff] [blame] | 2470 | } else |
| 2471 | ret = VM_FAULT_LOCKED; |
Nick Piggin | c2ec175 | 2009-03-31 15:23:21 -0700 | [diff] [blame] | 2472 | |
Nick Piggin | b827e49 | 2009-04-30 15:08:16 -0700 | [diff] [blame] | 2473 | out: |
David Chinner | 5417169 | 2007-07-19 17:39:55 +1000 | [diff] [blame] | 2474 | return ret; |
| 2475 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2476 | EXPORT_SYMBOL(block_page_mkwrite); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2477 | |
| 2478 | /* |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2479 | * nobh_write_begin()'s prereads are special: the buffer_heads are freed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2480 | * immediately, while under the page lock. So it needs a special end_io |
| 2481 | * handler which does not touch the bh after unlocking it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2482 | */ |
| 2483 | static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate) |
| 2484 | { |
Dmitry Monakhov | 68671f3 | 2007-10-16 01:24:47 -0700 | [diff] [blame] | 2485 | __end_buffer_read_notouch(bh, uptodate); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2486 | } |
| 2487 | |
| 2488 | /* |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2489 | * Attach the singly-linked list of buffers created by nobh_write_begin, to |
| 2490 | * the page (converting it to circular linked list and taking care of page |
| 2491 | * dirty races). |
| 2492 | */ |
| 2493 | static void attach_nobh_buffers(struct page *page, struct buffer_head *head) |
| 2494 | { |
| 2495 | struct buffer_head *bh; |
| 2496 | |
| 2497 | BUG_ON(!PageLocked(page)); |
| 2498 | |
| 2499 | spin_lock(&page->mapping->private_lock); |
| 2500 | bh = head; |
| 2501 | do { |
| 2502 | if (PageDirty(page)) |
| 2503 | set_buffer_dirty(bh); |
| 2504 | if (!bh->b_this_page) |
| 2505 | bh->b_this_page = head; |
| 2506 | bh = bh->b_this_page; |
| 2507 | } while (bh != head); |
| 2508 | attach_page_buffers(page, head); |
| 2509 | spin_unlock(&page->mapping->private_lock); |
| 2510 | } |
| 2511 | |
| 2512 | /* |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2513 | * Filesystems implementing the new truncate sequence should use the |
| 2514 | * _newtrunc postfix variant which won't incorrectly call vmtruncate. |
| 2515 | * The filesystem needs to handle block truncation upon failure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2516 | */ |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2517 | int nobh_write_begin_newtrunc(struct file *file, struct address_space *mapping, |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2518 | loff_t pos, unsigned len, unsigned flags, |
| 2519 | struct page **pagep, void **fsdata, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2520 | get_block_t *get_block) |
| 2521 | { |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2522 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2523 | const unsigned blkbits = inode->i_blkbits; |
| 2524 | const unsigned blocksize = 1 << blkbits; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2525 | struct buffer_head *head, *bh; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2526 | struct page *page; |
| 2527 | pgoff_t index; |
| 2528 | unsigned from, to; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2529 | unsigned block_in_page; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2530 | unsigned block_start, block_end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2531 | sector_t block_in_file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2532 | int nr_reads = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2533 | int ret = 0; |
| 2534 | int is_mapped_to_disk = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2535 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2536 | index = pos >> PAGE_CACHE_SHIFT; |
| 2537 | from = pos & (PAGE_CACHE_SIZE - 1); |
| 2538 | to = from + len; |
| 2539 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2540 | page = grab_cache_page_write_begin(mapping, index, flags); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2541 | if (!page) |
| 2542 | return -ENOMEM; |
| 2543 | *pagep = page; |
| 2544 | *fsdata = NULL; |
| 2545 | |
| 2546 | if (page_has_buffers(page)) { |
| 2547 | unlock_page(page); |
| 2548 | page_cache_release(page); |
| 2549 | *pagep = NULL; |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2550 | return block_write_begin_newtrunc(file, mapping, pos, len, |
| 2551 | flags, pagep, fsdata, get_block); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2552 | } |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2553 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2554 | if (PageMappedToDisk(page)) |
| 2555 | return 0; |
| 2556 | |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2557 | /* |
| 2558 | * Allocate buffers so that we can keep track of state, and potentially |
| 2559 | * attach them to the page if an error occurs. In the common case of |
| 2560 | * no error, they will just be freed again without ever being attached |
| 2561 | * to the page (which is all OK, because we're under the page lock). |
| 2562 | * |
| 2563 | * Be careful: the buffer linked list is a NULL terminated one, rather |
| 2564 | * than the circular one we're used to. |
| 2565 | */ |
| 2566 | head = alloc_page_buffers(page, blocksize, 0); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2567 | if (!head) { |
| 2568 | ret = -ENOMEM; |
| 2569 | goto out_release; |
| 2570 | } |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2571 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2572 | block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2573 | |
| 2574 | /* |
| 2575 | * We loop across all blocks in the page, whether or not they are |
| 2576 | * part of the affected region. This is so we can discover if the |
| 2577 | * page is fully mapped-to-disk. |
| 2578 | */ |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2579 | for (block_start = 0, block_in_page = 0, bh = head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2580 | block_start < PAGE_CACHE_SIZE; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2581 | block_in_page++, block_start += blocksize, bh = bh->b_this_page) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2582 | int create; |
| 2583 | |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2584 | block_end = block_start + blocksize; |
| 2585 | bh->b_state = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2586 | create = 1; |
| 2587 | if (block_start >= to) |
| 2588 | create = 0; |
| 2589 | ret = get_block(inode, block_in_file + block_in_page, |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2590 | bh, create); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2591 | if (ret) |
| 2592 | goto failed; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2593 | if (!buffer_mapped(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2594 | is_mapped_to_disk = 0; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2595 | if (buffer_new(bh)) |
| 2596 | unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); |
| 2597 | if (PageUptodate(page)) { |
| 2598 | set_buffer_uptodate(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2599 | continue; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2600 | } |
| 2601 | if (buffer_new(bh) || !buffer_mapped(bh)) { |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2602 | zero_user_segments(page, block_start, from, |
| 2603 | to, block_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2604 | continue; |
| 2605 | } |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2606 | if (buffer_uptodate(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2607 | continue; /* reiserfs does this */ |
| 2608 | if (block_start < from || block_end > to) { |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2609 | lock_buffer(bh); |
| 2610 | bh->b_end_io = end_buffer_read_nobh; |
| 2611 | submit_bh(READ, bh); |
| 2612 | nr_reads++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2613 | } |
| 2614 | } |
| 2615 | |
| 2616 | if (nr_reads) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2617 | /* |
| 2618 | * The page is locked, so these buffers are protected from |
| 2619 | * any VM or truncate activity. Hence we don't need to care |
| 2620 | * for the buffer_head refcounts. |
| 2621 | */ |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2622 | for (bh = head; bh; bh = bh->b_this_page) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2623 | wait_on_buffer(bh); |
| 2624 | if (!buffer_uptodate(bh)) |
| 2625 | ret = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2626 | } |
| 2627 | if (ret) |
| 2628 | goto failed; |
| 2629 | } |
| 2630 | |
| 2631 | if (is_mapped_to_disk) |
| 2632 | SetPageMappedToDisk(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2633 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2634 | *fsdata = head; /* to be released by nobh_write_end */ |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2635 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2636 | return 0; |
| 2637 | |
| 2638 | failed: |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2639 | BUG_ON(!ret); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2640 | /* |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2641 | * Error recovery is a bit difficult. We need to zero out blocks that |
| 2642 | * were newly allocated, and dirty them to ensure they get written out. |
| 2643 | * Buffers need to be attached to the page at this point, otherwise |
| 2644 | * the handling of potential IO errors during writeout would be hard |
| 2645 | * (could try doing synchronous writeout, but what if that fails too?) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2646 | */ |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2647 | attach_nobh_buffers(page, head); |
| 2648 | page_zero_new_buffers(page, from, to); |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2649 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2650 | out_release: |
| 2651 | unlock_page(page); |
| 2652 | page_cache_release(page); |
| 2653 | *pagep = NULL; |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2654 | |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 2655 | return ret; |
| 2656 | } |
| 2657 | EXPORT_SYMBOL(nobh_write_begin_newtrunc); |
| 2658 | |
| 2659 | /* |
| 2660 | * On entry, the page is fully not uptodate. |
| 2661 | * On exit the page is fully uptodate in the areas outside (from,to) |
| 2662 | */ |
| 2663 | int nobh_write_begin(struct file *file, struct address_space *mapping, |
| 2664 | loff_t pos, unsigned len, unsigned flags, |
| 2665 | struct page **pagep, void **fsdata, |
| 2666 | get_block_t *get_block) |
| 2667 | { |
| 2668 | int ret; |
| 2669 | |
| 2670 | ret = nobh_write_begin_newtrunc(file, mapping, pos, len, flags, |
| 2671 | pagep, fsdata, get_block); |
| 2672 | |
| 2673 | /* |
| 2674 | * prepare_write() may have instantiated a few blocks |
| 2675 | * outside i_size. Trim these off again. Don't need |
| 2676 | * i_size_read because we hold i_mutex. |
| 2677 | */ |
| 2678 | if (unlikely(ret)) { |
| 2679 | loff_t isize = mapping->host->i_size; |
| 2680 | if (pos + len > isize) |
| 2681 | vmtruncate(mapping->host, isize); |
| 2682 | } |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2683 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2684 | return ret; |
| 2685 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2686 | EXPORT_SYMBOL(nobh_write_begin); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2687 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2688 | int nobh_write_end(struct file *file, struct address_space *mapping, |
| 2689 | loff_t pos, unsigned len, unsigned copied, |
| 2690 | struct page *page, void *fsdata) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2691 | { |
| 2692 | struct inode *inode = page->mapping->host; |
Nick Piggin | efdc313 | 2007-10-21 06:57:41 +0200 | [diff] [blame] | 2693 | struct buffer_head *head = fsdata; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2694 | struct buffer_head *bh; |
Dmitri Monakhov | 5b41e74 | 2008-03-28 14:15:52 -0700 | [diff] [blame] | 2695 | BUG_ON(fsdata != NULL && page_has_buffers(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2696 | |
Dave Kleikamp | d4cf109 | 2009-02-06 14:59:26 -0600 | [diff] [blame] | 2697 | if (unlikely(copied < len) && head) |
Dmitri Monakhov | 5b41e74 | 2008-03-28 14:15:52 -0700 | [diff] [blame] | 2698 | attach_nobh_buffers(page, head); |
| 2699 | if (page_has_buffers(page)) |
| 2700 | return generic_write_end(file, mapping, pos, len, |
| 2701 | copied, page, fsdata); |
Nick Piggin | a4b0672 | 2007-10-16 01:24:48 -0700 | [diff] [blame] | 2702 | |
Nick Piggin | 22c8ca7 | 2007-02-20 13:58:09 -0800 | [diff] [blame] | 2703 | SetPageUptodate(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2704 | set_page_dirty(page); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2705 | if (pos+copied > inode->i_size) { |
| 2706 | i_size_write(inode, pos+copied); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2707 | mark_inode_dirty(inode); |
| 2708 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2709 | |
| 2710 | unlock_page(page); |
| 2711 | page_cache_release(page); |
| 2712 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2713 | while (head) { |
| 2714 | bh = head; |
| 2715 | head = head->b_this_page; |
| 2716 | free_buffer_head(bh); |
| 2717 | } |
| 2718 | |
| 2719 | return copied; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2720 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2721 | EXPORT_SYMBOL(nobh_write_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2722 | |
| 2723 | /* |
| 2724 | * nobh_writepage() - based on block_full_write_page() except |
| 2725 | * that it tries to operate without attaching bufferheads to |
| 2726 | * the page. |
| 2727 | */ |
| 2728 | int nobh_writepage(struct page *page, get_block_t *get_block, |
| 2729 | struct writeback_control *wbc) |
| 2730 | { |
| 2731 | struct inode * const inode = page->mapping->host; |
| 2732 | loff_t i_size = i_size_read(inode); |
| 2733 | const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; |
| 2734 | unsigned offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2735 | int ret; |
| 2736 | |
| 2737 | /* Is the page fully inside i_size? */ |
| 2738 | if (page->index < end_index) |
| 2739 | goto out; |
| 2740 | |
| 2741 | /* Is the page fully outside i_size? (truncate in progress) */ |
| 2742 | offset = i_size & (PAGE_CACHE_SIZE-1); |
| 2743 | if (page->index >= end_index+1 || !offset) { |
| 2744 | /* |
| 2745 | * The page may have dirty, unmapped buffers. For example, |
| 2746 | * they may have been added in ext3_writepage(). Make them |
| 2747 | * freeable here, so the page does not leak. |
| 2748 | */ |
| 2749 | #if 0 |
| 2750 | /* Not really sure about this - do we need this ? */ |
| 2751 | if (page->mapping->a_ops->invalidatepage) |
| 2752 | page->mapping->a_ops->invalidatepage(page, offset); |
| 2753 | #endif |
| 2754 | unlock_page(page); |
| 2755 | return 0; /* don't care */ |
| 2756 | } |
| 2757 | |
| 2758 | /* |
| 2759 | * The page straddles i_size. It must be zeroed out on each and every |
| 2760 | * writepage invocation because it may be mmapped. "A file is mapped |
| 2761 | * in multiples of the page size. For a file that is not a multiple of |
| 2762 | * the page size, the remaining memory is zeroed when mapped, and |
| 2763 | * writes to that region are not written out to the file." |
| 2764 | */ |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2765 | zero_user_segment(page, offset, PAGE_CACHE_SIZE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2766 | out: |
| 2767 | ret = mpage_writepage(page, get_block, wbc); |
| 2768 | if (ret == -EAGAIN) |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2769 | ret = __block_write_full_page(inode, page, get_block, wbc, |
| 2770 | end_buffer_async_write); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2771 | return ret; |
| 2772 | } |
| 2773 | EXPORT_SYMBOL(nobh_writepage); |
| 2774 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2775 | int nobh_truncate_page(struct address_space *mapping, |
| 2776 | loff_t from, get_block_t *get_block) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2777 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2778 | pgoff_t index = from >> PAGE_CACHE_SHIFT; |
| 2779 | unsigned offset = from & (PAGE_CACHE_SIZE-1); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2780 | unsigned blocksize; |
| 2781 | sector_t iblock; |
| 2782 | unsigned length, pos; |
| 2783 | struct inode *inode = mapping->host; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2784 | struct page *page; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2785 | struct buffer_head map_bh; |
| 2786 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2787 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2788 | blocksize = 1 << inode->i_blkbits; |
| 2789 | length = offset & (blocksize - 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2790 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2791 | /* Block boundary? Nothing to do */ |
| 2792 | if (!length) |
| 2793 | return 0; |
| 2794 | |
| 2795 | length = blocksize - length; |
| 2796 | iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
| 2797 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2798 | page = grab_cache_page(mapping, index); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2799 | err = -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2800 | if (!page) |
| 2801 | goto out; |
| 2802 | |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2803 | if (page_has_buffers(page)) { |
| 2804 | has_buffers: |
| 2805 | unlock_page(page); |
| 2806 | page_cache_release(page); |
| 2807 | return block_truncate_page(mapping, from, get_block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2808 | } |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2809 | |
| 2810 | /* Find the buffer that contains "offset" */ |
| 2811 | pos = blocksize; |
| 2812 | while (offset >= pos) { |
| 2813 | iblock++; |
| 2814 | pos += blocksize; |
| 2815 | } |
| 2816 | |
Theodore Ts'o | 460bcf5 | 2009-05-12 07:37:56 -0400 | [diff] [blame] | 2817 | map_bh.b_size = blocksize; |
| 2818 | map_bh.b_state = 0; |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2819 | err = get_block(inode, iblock, &map_bh, 0); |
| 2820 | if (err) |
| 2821 | goto unlock; |
| 2822 | /* unmapped? It's a hole - nothing to do */ |
| 2823 | if (!buffer_mapped(&map_bh)) |
| 2824 | goto unlock; |
| 2825 | |
| 2826 | /* Ok, it's mapped. Make sure it's up-to-date */ |
| 2827 | if (!PageUptodate(page)) { |
| 2828 | err = mapping->a_ops->readpage(NULL, page); |
| 2829 | if (err) { |
| 2830 | page_cache_release(page); |
| 2831 | goto out; |
| 2832 | } |
| 2833 | lock_page(page); |
| 2834 | if (!PageUptodate(page)) { |
| 2835 | err = -EIO; |
| 2836 | goto unlock; |
| 2837 | } |
| 2838 | if (page_has_buffers(page)) |
| 2839 | goto has_buffers; |
| 2840 | } |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2841 | zero_user(page, offset, length); |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2842 | set_page_dirty(page); |
| 2843 | err = 0; |
| 2844 | |
| 2845 | unlock: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2846 | unlock_page(page); |
| 2847 | page_cache_release(page); |
| 2848 | out: |
Nick Piggin | 03158cd | 2007-10-16 01:25:25 -0700 | [diff] [blame] | 2849 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2850 | } |
| 2851 | EXPORT_SYMBOL(nobh_truncate_page); |
| 2852 | |
| 2853 | int block_truncate_page(struct address_space *mapping, |
| 2854 | loff_t from, get_block_t *get_block) |
| 2855 | { |
| 2856 | pgoff_t index = from >> PAGE_CACHE_SHIFT; |
| 2857 | unsigned offset = from & (PAGE_CACHE_SIZE-1); |
| 2858 | unsigned blocksize; |
Andrew Morton | 54b21a7 | 2006-01-08 01:03:05 -0800 | [diff] [blame] | 2859 | sector_t iblock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2860 | unsigned length, pos; |
| 2861 | struct inode *inode = mapping->host; |
| 2862 | struct page *page; |
| 2863 | struct buffer_head *bh; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2864 | int err; |
| 2865 | |
| 2866 | blocksize = 1 << inode->i_blkbits; |
| 2867 | length = offset & (blocksize - 1); |
| 2868 | |
| 2869 | /* Block boundary? Nothing to do */ |
| 2870 | if (!length) |
| 2871 | return 0; |
| 2872 | |
| 2873 | length = blocksize - length; |
Andrew Morton | 54b21a7 | 2006-01-08 01:03:05 -0800 | [diff] [blame] | 2874 | iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2875 | |
| 2876 | page = grab_cache_page(mapping, index); |
| 2877 | err = -ENOMEM; |
| 2878 | if (!page) |
| 2879 | goto out; |
| 2880 | |
| 2881 | if (!page_has_buffers(page)) |
| 2882 | create_empty_buffers(page, blocksize, 0); |
| 2883 | |
| 2884 | /* Find the buffer that contains "offset" */ |
| 2885 | bh = page_buffers(page); |
| 2886 | pos = blocksize; |
| 2887 | while (offset >= pos) { |
| 2888 | bh = bh->b_this_page; |
| 2889 | iblock++; |
| 2890 | pos += blocksize; |
| 2891 | } |
| 2892 | |
| 2893 | err = 0; |
| 2894 | if (!buffer_mapped(bh)) { |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 2895 | WARN_ON(bh->b_size != blocksize); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2896 | err = get_block(inode, iblock, bh, 0); |
| 2897 | if (err) |
| 2898 | goto unlock; |
| 2899 | /* unmapped? It's a hole - nothing to do */ |
| 2900 | if (!buffer_mapped(bh)) |
| 2901 | goto unlock; |
| 2902 | } |
| 2903 | |
| 2904 | /* Ok, it's mapped. Make sure it's up-to-date */ |
| 2905 | if (PageUptodate(page)) |
| 2906 | set_buffer_uptodate(bh); |
| 2907 | |
David Chinner | 33a266d | 2007-02-12 00:51:41 -0800 | [diff] [blame] | 2908 | if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2909 | err = -EIO; |
| 2910 | ll_rw_block(READ, 1, &bh); |
| 2911 | wait_on_buffer(bh); |
| 2912 | /* Uhhuh. Read error. Complain and punt. */ |
| 2913 | if (!buffer_uptodate(bh)) |
| 2914 | goto unlock; |
| 2915 | } |
| 2916 | |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2917 | zero_user(page, offset, length); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2918 | mark_buffer_dirty(bh); |
| 2919 | err = 0; |
| 2920 | |
| 2921 | unlock: |
| 2922 | unlock_page(page); |
| 2923 | page_cache_release(page); |
| 2924 | out: |
| 2925 | return err; |
| 2926 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2927 | EXPORT_SYMBOL(block_truncate_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2928 | |
| 2929 | /* |
| 2930 | * The generic ->writepage function for buffer-backed address_spaces |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2931 | * this form passes in the end_io handler used to finish the IO. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2932 | */ |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2933 | int block_write_full_page_endio(struct page *page, get_block_t *get_block, |
| 2934 | struct writeback_control *wbc, bh_end_io_t *handler) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2935 | { |
| 2936 | struct inode * const inode = page->mapping->host; |
| 2937 | loff_t i_size = i_size_read(inode); |
| 2938 | const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; |
| 2939 | unsigned offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2940 | |
| 2941 | /* Is the page fully inside i_size? */ |
| 2942 | if (page->index < end_index) |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2943 | return __block_write_full_page(inode, page, get_block, wbc, |
| 2944 | handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2945 | |
| 2946 | /* Is the page fully outside i_size? (truncate in progress) */ |
| 2947 | offset = i_size & (PAGE_CACHE_SIZE-1); |
| 2948 | if (page->index >= end_index+1 || !offset) { |
| 2949 | /* |
| 2950 | * The page may have dirty, unmapped buffers. For example, |
| 2951 | * they may have been added in ext3_writepage(). Make them |
| 2952 | * freeable here, so the page does not leak. |
| 2953 | */ |
Jan Kara | aaa4059 | 2005-10-30 15:00:16 -0800 | [diff] [blame] | 2954 | do_invalidatepage(page, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2955 | unlock_page(page); |
| 2956 | return 0; /* don't care */ |
| 2957 | } |
| 2958 | |
| 2959 | /* |
| 2960 | * The page straddles i_size. It must be zeroed out on each and every |
Adam Buchbinder | 2a61aa4 | 2009-12-11 16:35:40 -0500 | [diff] [blame] | 2961 | * writepage invocation because it may be mmapped. "A file is mapped |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2962 | * in multiples of the page size. For a file that is not a multiple of |
| 2963 | * the page size, the remaining memory is zeroed when mapped, and |
| 2964 | * writes to that region are not written out to the file." |
| 2965 | */ |
Christoph Lameter | eebd2aa | 2008-02-04 22:28:29 -0800 | [diff] [blame] | 2966 | zero_user_segment(page, offset, PAGE_CACHE_SIZE); |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2967 | return __block_write_full_page(inode, page, get_block, wbc, handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2968 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2969 | EXPORT_SYMBOL(block_write_full_page_endio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2970 | |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2971 | /* |
| 2972 | * The generic ->writepage function for buffer-backed address_spaces |
| 2973 | */ |
| 2974 | int block_write_full_page(struct page *page, get_block_t *get_block, |
| 2975 | struct writeback_control *wbc) |
| 2976 | { |
| 2977 | return block_write_full_page_endio(page, get_block, wbc, |
| 2978 | end_buffer_async_write); |
| 2979 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2980 | EXPORT_SYMBOL(block_write_full_page); |
Chris Mason | 35c80d5 | 2009-04-15 13:22:38 -0400 | [diff] [blame] | 2981 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2982 | sector_t generic_block_bmap(struct address_space *mapping, sector_t block, |
| 2983 | get_block_t *get_block) |
| 2984 | { |
| 2985 | struct buffer_head tmp; |
| 2986 | struct inode *inode = mapping->host; |
| 2987 | tmp.b_state = 0; |
| 2988 | tmp.b_blocknr = 0; |
Badari Pulavarty | b0cf232 | 2006-03-26 01:38:00 -0800 | [diff] [blame] | 2989 | tmp.b_size = 1 << inode->i_blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2990 | get_block(inode, block, &tmp, 0); |
| 2991 | return tmp.b_blocknr; |
| 2992 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 2993 | EXPORT_SYMBOL(generic_block_bmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2994 | |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 2995 | static void end_bio_bh_io_sync(struct bio *bio, int err) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2996 | { |
| 2997 | struct buffer_head *bh = bio->bi_private; |
| 2998 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2999 | if (err == -EOPNOTSUPP) { |
| 3000 | set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); |
| 3001 | set_bit(BH_Eopnotsupp, &bh->b_state); |
| 3002 | } |
| 3003 | |
Keith Mannthey | 08bafc0 | 2008-11-25 10:24:35 +0100 | [diff] [blame] | 3004 | if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags))) |
| 3005 | set_bit(BH_Quiet, &bh->b_state); |
| 3006 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3007 | bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); |
| 3008 | bio_put(bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3009 | } |
| 3010 | |
| 3011 | int submit_bh(int rw, struct buffer_head * bh) |
| 3012 | { |
| 3013 | struct bio *bio; |
| 3014 | int ret = 0; |
| 3015 | |
| 3016 | BUG_ON(!buffer_locked(bh)); |
| 3017 | BUG_ON(!buffer_mapped(bh)); |
| 3018 | BUG_ON(!bh->b_end_io); |
Aneesh Kumar K.V | 8fb0e34 | 2009-05-12 16:22:37 -0400 | [diff] [blame] | 3019 | BUG_ON(buffer_delay(bh)); |
| 3020 | BUG_ON(buffer_unwritten(bh)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3021 | |
Jens Axboe | 48fd4f9 | 2008-08-22 10:00:36 +0200 | [diff] [blame] | 3022 | /* |
| 3023 | * Mask in barrier bit for a write (could be either a WRITE or a |
| 3024 | * WRITE_SYNC |
| 3025 | */ |
| 3026 | if (buffer_ordered(bh) && (rw & WRITE)) |
| 3027 | rw |= WRITE_BARRIER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3028 | |
| 3029 | /* |
Jens Axboe | 48fd4f9 | 2008-08-22 10:00:36 +0200 | [diff] [blame] | 3030 | * Only clear out a write error when rewriting |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3031 | */ |
Jens Axboe | 48fd4f9 | 2008-08-22 10:00:36 +0200 | [diff] [blame] | 3032 | if (test_set_buffer_req(bh) && (rw & WRITE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3033 | clear_buffer_write_io_error(bh); |
| 3034 | |
| 3035 | /* |
| 3036 | * from here on down, it's all bio -- do the initial mapping, |
| 3037 | * submit_bio -> generic_make_request may further map this bio around |
| 3038 | */ |
| 3039 | bio = bio_alloc(GFP_NOIO, 1); |
| 3040 | |
| 3041 | bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
| 3042 | bio->bi_bdev = bh->b_bdev; |
| 3043 | bio->bi_io_vec[0].bv_page = bh->b_page; |
| 3044 | bio->bi_io_vec[0].bv_len = bh->b_size; |
| 3045 | bio->bi_io_vec[0].bv_offset = bh_offset(bh); |
| 3046 | |
| 3047 | bio->bi_vcnt = 1; |
| 3048 | bio->bi_idx = 0; |
| 3049 | bio->bi_size = bh->b_size; |
| 3050 | |
| 3051 | bio->bi_end_io = end_bio_bh_io_sync; |
| 3052 | bio->bi_private = bh; |
| 3053 | |
| 3054 | bio_get(bio); |
| 3055 | submit_bio(rw, bio); |
| 3056 | |
| 3057 | if (bio_flagged(bio, BIO_EOPNOTSUPP)) |
| 3058 | ret = -EOPNOTSUPP; |
| 3059 | |
| 3060 | bio_put(bio); |
| 3061 | return ret; |
| 3062 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 3063 | EXPORT_SYMBOL(submit_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3064 | |
| 3065 | /** |
| 3066 | * ll_rw_block: low-level access to block devices (DEPRECATED) |
Jan Kara | a766223 | 2005-09-06 15:19:10 -0700 | [diff] [blame] | 3067 | * @rw: whether to %READ or %WRITE or %SWRITE or maybe %READA (readahead) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3068 | * @nr: number of &struct buffer_heads in the array |
| 3069 | * @bhs: array of pointers to &struct buffer_head |
| 3070 | * |
Jan Kara | a766223 | 2005-09-06 15:19:10 -0700 | [diff] [blame] | 3071 | * ll_rw_block() takes an array of pointers to &struct buffer_heads, and |
| 3072 | * requests an I/O operation on them, either a %READ or a %WRITE. The third |
| 3073 | * %SWRITE is like %WRITE only we make sure that the *current* data in buffers |
| 3074 | * are sent to disk. The fourth %READA option is described in the documentation |
| 3075 | * for generic_make_request() which ll_rw_block() calls. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3076 | * |
| 3077 | * This function drops any buffer that it cannot get a lock on (with the |
Jan Kara | a766223 | 2005-09-06 15:19:10 -0700 | [diff] [blame] | 3078 | * BH_Lock state bit) unless SWRITE is required, any buffer that appears to be |
| 3079 | * clean when doing a write request, and any buffer that appears to be |
| 3080 | * up-to-date when doing read request. Further it marks as clean buffers that |
| 3081 | * are processed for writing (the buffer cache won't assume that they are |
| 3082 | * actually clean until the buffer gets unlocked). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3083 | * |
| 3084 | * ll_rw_block sets b_end_io to simple completion handler that marks |
| 3085 | * the buffer up-to-date (if approriate), unlocks the buffer and wakes |
| 3086 | * any waiters. |
| 3087 | * |
| 3088 | * All of the buffers must be for the same device, and must also be a |
| 3089 | * multiple of the current approved size for the device. |
| 3090 | */ |
| 3091 | void ll_rw_block(int rw, int nr, struct buffer_head *bhs[]) |
| 3092 | { |
| 3093 | int i; |
| 3094 | |
| 3095 | for (i = 0; i < nr; i++) { |
| 3096 | struct buffer_head *bh = bhs[i]; |
| 3097 | |
Jens Axboe | 9cf6b72 | 2009-04-06 14:48:03 +0200 | [diff] [blame] | 3098 | if (rw == SWRITE || rw == SWRITE_SYNC || rw == SWRITE_SYNC_PLUG) |
Jan Kara | a766223 | 2005-09-06 15:19:10 -0700 | [diff] [blame] | 3099 | lock_buffer(bh); |
Nick Piggin | ca5de40 | 2008-08-02 12:02:13 +0200 | [diff] [blame] | 3100 | else if (!trylock_buffer(bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3101 | continue; |
| 3102 | |
Jens Axboe | 9cf6b72 | 2009-04-06 14:48:03 +0200 | [diff] [blame] | 3103 | if (rw == WRITE || rw == SWRITE || rw == SWRITE_SYNC || |
| 3104 | rw == SWRITE_SYNC_PLUG) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3105 | if (test_clear_buffer_dirty(bh)) { |
akpm@osdl.org | 76c3073 | 2005-04-16 15:24:07 -0700 | [diff] [blame] | 3106 | bh->b_end_io = end_buffer_write_sync; |
OGAWA Hirofumi | e60e5c5 | 2006-02-03 03:04:43 -0800 | [diff] [blame] | 3107 | get_bh(bh); |
Jens Axboe | 18ce375 | 2008-07-01 09:07:34 +0200 | [diff] [blame] | 3108 | if (rw == SWRITE_SYNC) |
| 3109 | submit_bh(WRITE_SYNC, bh); |
| 3110 | else |
| 3111 | submit_bh(WRITE, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3112 | continue; |
| 3113 | } |
| 3114 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3115 | if (!buffer_uptodate(bh)) { |
akpm@osdl.org | 76c3073 | 2005-04-16 15:24:07 -0700 | [diff] [blame] | 3116 | bh->b_end_io = end_buffer_read_sync; |
OGAWA Hirofumi | e60e5c5 | 2006-02-03 03:04:43 -0800 | [diff] [blame] | 3117 | get_bh(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3118 | submit_bh(rw, bh); |
| 3119 | continue; |
| 3120 | } |
| 3121 | } |
| 3122 | unlock_buffer(bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3123 | } |
| 3124 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 3125 | EXPORT_SYMBOL(ll_rw_block); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3126 | |
| 3127 | /* |
| 3128 | * For a data-integrity writeout, we need to wait upon any in-progress I/O |
| 3129 | * and then start new I/O and then wait upon it. The caller must have a ref on |
| 3130 | * the buffer_head. |
| 3131 | */ |
| 3132 | int sync_dirty_buffer(struct buffer_head *bh) |
| 3133 | { |
| 3134 | int ret = 0; |
| 3135 | |
| 3136 | WARN_ON(atomic_read(&bh->b_count) < 1); |
| 3137 | lock_buffer(bh); |
| 3138 | if (test_clear_buffer_dirty(bh)) { |
| 3139 | get_bh(bh); |
| 3140 | bh->b_end_io = end_buffer_write_sync; |
Jens Axboe | 1aa2a7c | 2009-04-06 14:48:08 +0200 | [diff] [blame] | 3141 | ret = submit_bh(WRITE_SYNC, bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3142 | wait_on_buffer(bh); |
| 3143 | if (buffer_eopnotsupp(bh)) { |
| 3144 | clear_buffer_eopnotsupp(bh); |
| 3145 | ret = -EOPNOTSUPP; |
| 3146 | } |
| 3147 | if (!ret && !buffer_uptodate(bh)) |
| 3148 | ret = -EIO; |
| 3149 | } else { |
| 3150 | unlock_buffer(bh); |
| 3151 | } |
| 3152 | return ret; |
| 3153 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 3154 | EXPORT_SYMBOL(sync_dirty_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3155 | |
| 3156 | /* |
| 3157 | * try_to_free_buffers() checks if all the buffers on this particular page |
| 3158 | * are unused, and releases them if so. |
| 3159 | * |
| 3160 | * Exclusion against try_to_free_buffers may be obtained by either |
| 3161 | * locking the page or by holding its mapping's private_lock. |
| 3162 | * |
| 3163 | * If the page is dirty but all the buffers are clean then we need to |
| 3164 | * be sure to mark the page clean as well. This is because the page |
| 3165 | * may be against a block device, and a later reattachment of buffers |
| 3166 | * to a dirty page will set *all* buffers dirty. Which would corrupt |
| 3167 | * filesystem data on the same device. |
| 3168 | * |
| 3169 | * The same applies to regular filesystem pages: if all the buffers are |
| 3170 | * clean then we set the page clean and proceed. To do that, we require |
| 3171 | * total exclusion from __set_page_dirty_buffers(). That is obtained with |
| 3172 | * private_lock. |
| 3173 | * |
| 3174 | * try_to_free_buffers() is non-blocking. |
| 3175 | */ |
| 3176 | static inline int buffer_busy(struct buffer_head *bh) |
| 3177 | { |
| 3178 | return atomic_read(&bh->b_count) | |
| 3179 | (bh->b_state & ((1 << BH_Dirty) | (1 << BH_Lock))); |
| 3180 | } |
| 3181 | |
| 3182 | static int |
| 3183 | drop_buffers(struct page *page, struct buffer_head **buffers_to_free) |
| 3184 | { |
| 3185 | struct buffer_head *head = page_buffers(page); |
| 3186 | struct buffer_head *bh; |
| 3187 | |
| 3188 | bh = head; |
| 3189 | do { |
akpm@osdl.org | de7d5a3 | 2005-05-01 08:58:39 -0700 | [diff] [blame] | 3190 | if (buffer_write_io_error(bh) && page->mapping) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3191 | set_bit(AS_EIO, &page->mapping->flags); |
| 3192 | if (buffer_busy(bh)) |
| 3193 | goto failed; |
| 3194 | bh = bh->b_this_page; |
| 3195 | } while (bh != head); |
| 3196 | |
| 3197 | do { |
| 3198 | struct buffer_head *next = bh->b_this_page; |
| 3199 | |
Jan Kara | 535ee2f | 2008-02-08 04:21:59 -0800 | [diff] [blame] | 3200 | if (bh->b_assoc_map) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3201 | __remove_assoc_queue(bh); |
| 3202 | bh = next; |
| 3203 | } while (bh != head); |
| 3204 | *buffers_to_free = head; |
| 3205 | __clear_page_buffers(page); |
| 3206 | return 1; |
| 3207 | failed: |
| 3208 | return 0; |
| 3209 | } |
| 3210 | |
| 3211 | int try_to_free_buffers(struct page *page) |
| 3212 | { |
| 3213 | struct address_space * const mapping = page->mapping; |
| 3214 | struct buffer_head *buffers_to_free = NULL; |
| 3215 | int ret = 0; |
| 3216 | |
| 3217 | BUG_ON(!PageLocked(page)); |
Linus Torvalds | ecdfc97 | 2007-01-26 12:47:06 -0800 | [diff] [blame] | 3218 | if (PageWriteback(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3219 | return 0; |
| 3220 | |
| 3221 | if (mapping == NULL) { /* can this still happen? */ |
| 3222 | ret = drop_buffers(page, &buffers_to_free); |
| 3223 | goto out; |
| 3224 | } |
| 3225 | |
| 3226 | spin_lock(&mapping->private_lock); |
| 3227 | ret = drop_buffers(page, &buffers_to_free); |
Linus Torvalds | ecdfc97 | 2007-01-26 12:47:06 -0800 | [diff] [blame] | 3228 | |
| 3229 | /* |
| 3230 | * If the filesystem writes its buffers by hand (eg ext3) |
| 3231 | * then we can have clean buffers against a dirty page. We |
| 3232 | * clean the page here; otherwise the VM will never notice |
| 3233 | * that the filesystem did any IO at all. |
| 3234 | * |
| 3235 | * Also, during truncate, discard_buffer will have marked all |
| 3236 | * the page's buffers clean. We discover that here and clean |
| 3237 | * the page also. |
Nick Piggin | 87df724 | 2007-01-30 14:36:27 +1100 | [diff] [blame] | 3238 | * |
| 3239 | * private_lock must be held over this entire operation in order |
| 3240 | * to synchronise against __set_page_dirty_buffers and prevent the |
| 3241 | * dirty bit from being lost. |
Linus Torvalds | ecdfc97 | 2007-01-26 12:47:06 -0800 | [diff] [blame] | 3242 | */ |
| 3243 | if (ret) |
| 3244 | cancel_dirty_page(page, PAGE_CACHE_SIZE); |
Nick Piggin | 87df724 | 2007-01-30 14:36:27 +1100 | [diff] [blame] | 3245 | spin_unlock(&mapping->private_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3246 | out: |
| 3247 | if (buffers_to_free) { |
| 3248 | struct buffer_head *bh = buffers_to_free; |
| 3249 | |
| 3250 | do { |
| 3251 | struct buffer_head *next = bh->b_this_page; |
| 3252 | free_buffer_head(bh); |
| 3253 | bh = next; |
| 3254 | } while (bh != buffers_to_free); |
| 3255 | } |
| 3256 | return ret; |
| 3257 | } |
| 3258 | EXPORT_SYMBOL(try_to_free_buffers); |
| 3259 | |
NeilBrown | 3978d71 | 2006-03-26 01:37:17 -0800 | [diff] [blame] | 3260 | void block_sync_page(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3261 | { |
| 3262 | struct address_space *mapping; |
| 3263 | |
| 3264 | smp_mb(); |
| 3265 | mapping = page_mapping(page); |
| 3266 | if (mapping) |
| 3267 | blk_run_backing_dev(mapping->backing_dev_info, page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3268 | } |
H Hartley Sweeten | 1fe72ea | 2009-09-22 16:43:51 -0700 | [diff] [blame] | 3269 | EXPORT_SYMBOL(block_sync_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3270 | |
| 3271 | /* |
| 3272 | * There are no bdflush tunables left. But distributions are |
| 3273 | * still running obsolete flush daemons, so we terminate them here. |
| 3274 | * |
| 3275 | * Use of bdflush() is deprecated and will be removed in a future kernel. |
Jens Axboe | 5b0830c | 2009-09-23 19:37:09 +0200 | [diff] [blame] | 3276 | * The `flush-X' kernel threads fully replace bdflush daemons and this call. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3277 | */ |
Heiko Carstens | bdc480e | 2009-01-14 14:14:12 +0100 | [diff] [blame] | 3278 | SYSCALL_DEFINE2(bdflush, int, func, long, data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3279 | { |
| 3280 | static int msg_count; |
| 3281 | |
| 3282 | if (!capable(CAP_SYS_ADMIN)) |
| 3283 | return -EPERM; |
| 3284 | |
| 3285 | if (msg_count < 5) { |
| 3286 | msg_count++; |
| 3287 | printk(KERN_INFO |
| 3288 | "warning: process `%s' used the obsolete bdflush" |
| 3289 | " system call\n", current->comm); |
| 3290 | printk(KERN_INFO "Fix your initscripts?\n"); |
| 3291 | } |
| 3292 | |
| 3293 | if (func == 1) |
| 3294 | do_exit(0); |
| 3295 | return 0; |
| 3296 | } |
| 3297 | |
| 3298 | /* |
| 3299 | * Buffer-head allocation |
| 3300 | */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 3301 | static struct kmem_cache *bh_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3302 | |
| 3303 | /* |
| 3304 | * Once the number of bh's in the machine exceeds this level, we start |
| 3305 | * stripping them in writeback. |
| 3306 | */ |
| 3307 | static int max_buffer_heads; |
| 3308 | |
| 3309 | int buffer_heads_over_limit; |
| 3310 | |
| 3311 | struct bh_accounting { |
| 3312 | int nr; /* Number of live bh's */ |
| 3313 | int ratelimit; /* Limit cacheline bouncing */ |
| 3314 | }; |
| 3315 | |
| 3316 | static DEFINE_PER_CPU(struct bh_accounting, bh_accounting) = {0, 0}; |
| 3317 | |
| 3318 | static void recalc_bh_state(void) |
| 3319 | { |
| 3320 | int i; |
| 3321 | int tot = 0; |
| 3322 | |
| 3323 | if (__get_cpu_var(bh_accounting).ratelimit++ < 4096) |
| 3324 | return; |
| 3325 | __get_cpu_var(bh_accounting).ratelimit = 0; |
Eric Dumazet | 8a14342 | 2006-03-24 03:18:10 -0800 | [diff] [blame] | 3326 | for_each_online_cpu(i) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3327 | tot += per_cpu(bh_accounting, i).nr; |
| 3328 | buffer_heads_over_limit = (tot > max_buffer_heads); |
| 3329 | } |
| 3330 | |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 3331 | struct buffer_head *alloc_buffer_head(gfp_t gfp_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3332 | { |
Richard Kennedy | 019b4d1 | 2010-03-10 15:20:33 -0800 | [diff] [blame] | 3333 | struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3334 | if (ret) { |
Christoph Lameter | a35afb8 | 2007-05-16 22:10:57 -0700 | [diff] [blame] | 3335 | INIT_LIST_HEAD(&ret->b_assoc_buffers); |
Coywolf Qi Hunt | 736c7b8 | 2005-09-06 15:18:17 -0700 | [diff] [blame] | 3336 | get_cpu_var(bh_accounting).nr++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3337 | recalc_bh_state(); |
Coywolf Qi Hunt | 736c7b8 | 2005-09-06 15:18:17 -0700 | [diff] [blame] | 3338 | put_cpu_var(bh_accounting); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3339 | } |
| 3340 | return ret; |
| 3341 | } |
| 3342 | EXPORT_SYMBOL(alloc_buffer_head); |
| 3343 | |
| 3344 | void free_buffer_head(struct buffer_head *bh) |
| 3345 | { |
| 3346 | BUG_ON(!list_empty(&bh->b_assoc_buffers)); |
| 3347 | kmem_cache_free(bh_cachep, bh); |
Coywolf Qi Hunt | 736c7b8 | 2005-09-06 15:18:17 -0700 | [diff] [blame] | 3348 | get_cpu_var(bh_accounting).nr--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3349 | recalc_bh_state(); |
Coywolf Qi Hunt | 736c7b8 | 2005-09-06 15:18:17 -0700 | [diff] [blame] | 3350 | put_cpu_var(bh_accounting); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3351 | } |
| 3352 | EXPORT_SYMBOL(free_buffer_head); |
| 3353 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3354 | static void buffer_exit_cpu(int cpu) |
| 3355 | { |
| 3356 | int i; |
| 3357 | struct bh_lru *b = &per_cpu(bh_lrus, cpu); |
| 3358 | |
| 3359 | for (i = 0; i < BH_LRU_SIZE; i++) { |
| 3360 | brelse(b->bhs[i]); |
| 3361 | b->bhs[i] = NULL; |
| 3362 | } |
Eric Dumazet | 8a14342 | 2006-03-24 03:18:10 -0800 | [diff] [blame] | 3363 | get_cpu_var(bh_accounting).nr += per_cpu(bh_accounting, cpu).nr; |
| 3364 | per_cpu(bh_accounting, cpu).nr = 0; |
| 3365 | put_cpu_var(bh_accounting); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3366 | } |
| 3367 | |
| 3368 | static int buffer_cpu_notify(struct notifier_block *self, |
| 3369 | unsigned long action, void *hcpu) |
| 3370 | { |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 3371 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3372 | buffer_exit_cpu((unsigned long)hcpu); |
| 3373 | return NOTIFY_OK; |
| 3374 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3375 | |
Aneesh Kumar K.V | 389d1b0 | 2008-01-28 23:58:26 -0500 | [diff] [blame] | 3376 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 3377 | * bh_uptodate_or_lock - Test whether the buffer is uptodate |
Aneesh Kumar K.V | 389d1b0 | 2008-01-28 23:58:26 -0500 | [diff] [blame] | 3378 | * @bh: struct buffer_head |
| 3379 | * |
| 3380 | * Return true if the buffer is up-to-date and false, |
| 3381 | * with the buffer locked, if not. |
| 3382 | */ |
| 3383 | int bh_uptodate_or_lock(struct buffer_head *bh) |
| 3384 | { |
| 3385 | if (!buffer_uptodate(bh)) { |
| 3386 | lock_buffer(bh); |
| 3387 | if (!buffer_uptodate(bh)) |
| 3388 | return 0; |
| 3389 | unlock_buffer(bh); |
| 3390 | } |
| 3391 | return 1; |
| 3392 | } |
| 3393 | EXPORT_SYMBOL(bh_uptodate_or_lock); |
| 3394 | |
| 3395 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 3396 | * bh_submit_read - Submit a locked buffer for reading |
Aneesh Kumar K.V | 389d1b0 | 2008-01-28 23:58:26 -0500 | [diff] [blame] | 3397 | * @bh: struct buffer_head |
| 3398 | * |
| 3399 | * Returns zero on success and -EIO on error. |
| 3400 | */ |
| 3401 | int bh_submit_read(struct buffer_head *bh) |
| 3402 | { |
| 3403 | BUG_ON(!buffer_locked(bh)); |
| 3404 | |
| 3405 | if (buffer_uptodate(bh)) { |
| 3406 | unlock_buffer(bh); |
| 3407 | return 0; |
| 3408 | } |
| 3409 | |
| 3410 | get_bh(bh); |
| 3411 | bh->b_end_io = end_buffer_read_sync; |
| 3412 | submit_bh(READ, bh); |
| 3413 | wait_on_buffer(bh); |
| 3414 | if (buffer_uptodate(bh)) |
| 3415 | return 0; |
| 3416 | return -EIO; |
| 3417 | } |
| 3418 | EXPORT_SYMBOL(bh_submit_read); |
| 3419 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3420 | void __init buffer_init(void) |
| 3421 | { |
| 3422 | int nrpages; |
| 3423 | |
Christoph Lameter | b98938c | 2008-02-04 22:28:36 -0800 | [diff] [blame] | 3424 | bh_cachep = kmem_cache_create("buffer_head", |
| 3425 | sizeof(struct buffer_head), 0, |
| 3426 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
| 3427 | SLAB_MEM_SPREAD), |
Richard Kennedy | 019b4d1 | 2010-03-10 15:20:33 -0800 | [diff] [blame] | 3428 | NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3429 | |
| 3430 | /* |
| 3431 | * Limit the bh occupancy to 10% of ZONE_NORMAL |
| 3432 | */ |
| 3433 | nrpages = (nr_free_buffer_pages() * 10) / 100; |
| 3434 | max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head)); |
| 3435 | hotcpu_notifier(buffer_cpu_notify, 0); |
| 3436 | } |