Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * fs/direct-io.c |
| 3 | * |
| 4 | * Copyright (C) 2002, Linus Torvalds. |
| 5 | * |
| 6 | * O_DIRECT |
| 7 | * |
Francois Cami | e1f8e87 | 2008-10-15 22:01:59 -0700 | [diff] [blame] | 8 | * 04Jul2002 Andrew Morton |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | * Initial version |
| 10 | * 11Sep2002 janetinc@us.ibm.com |
| 11 | * added readv/writev support. |
Francois Cami | e1f8e87 | 2008-10-15 22:01:59 -0700 | [diff] [blame] | 12 | * 29Oct2002 Andrew Morton |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | * rewrote bio_add_page() support. |
| 14 | * 30Oct2002 pbadari@us.ibm.com |
| 15 | * added support for non-aligned IO. |
| 16 | * 06Nov2002 pbadari@us.ibm.com |
| 17 | * added asynchronous IO support. |
| 18 | * 21Jul2003 nathans@sgi.com |
| 19 | * added IO completion notifier. |
| 20 | */ |
| 21 | |
| 22 | #include <linux/kernel.h> |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/types.h> |
| 25 | #include <linux/fs.h> |
| 26 | #include <linux/mm.h> |
| 27 | #include <linux/slab.h> |
| 28 | #include <linux/highmem.h> |
| 29 | #include <linux/pagemap.h> |
Andrew Morton | 98c4d57 | 2006-12-10 02:19:47 -0800 | [diff] [blame] | 30 | #include <linux/task_io_accounting_ops.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/bio.h> |
| 32 | #include <linux/wait.h> |
| 33 | #include <linux/err.h> |
| 34 | #include <linux/blkdev.h> |
| 35 | #include <linux/buffer_head.h> |
| 36 | #include <linux/rwsem.h> |
| 37 | #include <linux/uio.h> |
Arun Sharma | 60063497 | 2011-07-26 16:09:06 -0700 | [diff] [blame] | 38 | #include <linux/atomic.h> |
Andi Kleen | 65dd2aa | 2012-01-12 17:20:35 -0800 | [diff] [blame] | 39 | #include <linux/prefetch.h> |
Kent Overstreet | a27bb33 | 2013-05-07 16:19:08 -0700 | [diff] [blame] | 40 | #include <linux/aio.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | |
| 42 | /* |
| 43 | * How many user pages to map in one call to get_user_pages(). This determines |
Andi Kleen | cde1ecb | 2011-08-01 21:38:04 -0700 | [diff] [blame] | 44 | * the size of a structure in the slab cache |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | */ |
| 46 | #define DIO_PAGES 64 |
| 47 | |
| 48 | /* |
| 49 | * This code generally works in units of "dio_blocks". A dio_block is |
| 50 | * somewhere between the hard sector size and the filesystem block size. it |
| 51 | * is determined on a per-invocation basis. When talking to the filesystem |
| 52 | * we need to convert dio_blocks to fs_blocks by scaling the dio_block quantity |
| 53 | * down by dio->blkfactor. Similarly, fs-blocksize quantities are converted |
| 54 | * to bio_block quantities by shifting left by blkfactor. |
| 55 | * |
| 56 | * If blkfactor is zero then the user's request was aligned to the filesystem's |
| 57 | * blocksize. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | */ |
| 59 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 60 | /* dio_state only used in the submission path */ |
| 61 | |
| 62 | struct dio_submit { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | struct bio *bio; /* bio under assembly */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | unsigned blkbits; /* doesn't change */ |
| 65 | unsigned blkfactor; /* When we're using an alignment which |
| 66 | is finer than the filesystem's soft |
| 67 | blocksize, this specifies how much |
| 68 | finer. blkfactor=2 means 1/4-block |
| 69 | alignment. Does not change */ |
| 70 | unsigned start_zero_done; /* flag: sub-blocksize zeroing has |
| 71 | been performed at the start of a |
| 72 | write */ |
| 73 | int pages_in_io; /* approximate total IO pages */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | sector_t block_in_file; /* Current offset into the underlying |
| 75 | file in dio_block units. */ |
| 76 | unsigned blocks_available; /* At block_in_file. changes */ |
Andi Kleen | 0dc2bc4 | 2011-08-01 21:38:05 -0700 | [diff] [blame] | 77 | int reap_counter; /* rate limit reaping */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | sector_t final_block_in_request;/* doesn't change */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | int boundary; /* prev block is at a boundary */ |
Badari Pulavarty | 1d8fa7a | 2006-03-26 01:38:02 -0800 | [diff] [blame] | 80 | get_block_t *get_block; /* block mapping function */ |
Josef Bacik | facd07b | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 81 | dio_submit_t *submit_io; /* IO submition function */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 82 | |
Josef Bacik | facd07b | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 83 | loff_t logical_offset_in_bio; /* current first logical block in bio */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | sector_t final_block_in_bio; /* current final block in bio + 1 */ |
| 85 | sector_t next_block_for_io; /* next block to be put under IO, |
| 86 | in dio_blocks units */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | |
| 88 | /* |
| 89 | * Deferred addition of a page to the dio. These variables are |
| 90 | * private to dio_send_cur_page(), submit_page_section() and |
| 91 | * dio_bio_add_page(). |
| 92 | */ |
| 93 | struct page *cur_page; /* The page */ |
| 94 | unsigned cur_page_offset; /* Offset into it, in bytes */ |
| 95 | unsigned cur_page_len; /* Nr of bytes at cur_page_offset */ |
| 96 | sector_t cur_page_block; /* Where it starts */ |
Josef Bacik | facd07b | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 97 | loff_t cur_page_fs_offset; /* Offset in file */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 99 | struct iov_iter *iter; |
Jeff Moyer | 23aee09 | 2009-12-15 16:47:49 -0800 | [diff] [blame] | 100 | /* |
| 101 | * Page queue. These variables belong to dio_refill_pages() and |
| 102 | * dio_get_page(). |
| 103 | */ |
| 104 | unsigned head; /* next page to process */ |
| 105 | unsigned tail; /* last valid page + 1 */ |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 106 | size_t from, to; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 107 | }; |
| 108 | |
| 109 | /* dio_state communicated between submission path and end_io */ |
| 110 | struct dio { |
| 111 | int flags; /* doesn't change */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 112 | int rw; |
Andi Kleen | 0dc2bc4 | 2011-08-01 21:38:05 -0700 | [diff] [blame] | 113 | struct inode *inode; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 114 | loff_t i_size; /* i_size when submitted */ |
| 115 | dio_iodone_t *end_io; /* IO completion function */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 116 | |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 117 | void *private; /* copy from map_bh.b_private */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 118 | |
| 119 | /* BIO completion state */ |
| 120 | spinlock_t bio_lock; /* protects BIO fields below */ |
Andi Kleen | 0dc2bc4 | 2011-08-01 21:38:05 -0700 | [diff] [blame] | 121 | int page_errors; /* errno from get_user_pages() */ |
| 122 | int is_async; /* is IO async ? */ |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 123 | bool defer_completion; /* defer AIO completion to workqueue? */ |
Andi Kleen | 0dc2bc4 | 2011-08-01 21:38:05 -0700 | [diff] [blame] | 124 | int io_error; /* IO error in completion path */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 125 | unsigned long refcount; /* direct_io_worker() and bios */ |
| 126 | struct bio *bio_list; /* singly linked via bi_private */ |
| 127 | struct task_struct *waiter; /* waiting task (NULL if none) */ |
| 128 | |
| 129 | /* AIO related stuff */ |
| 130 | struct kiocb *iocb; /* kiocb */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 131 | ssize_t result; /* IO result */ |
| 132 | |
Jeff Moyer | 23aee09 | 2009-12-15 16:47:49 -0800 | [diff] [blame] | 133 | /* |
| 134 | * pages[] (and any fields placed after it) are not zeroed out at |
| 135 | * allocation time. Don't add new fields after pages[] unless you |
| 136 | * wish that they not be zeroed. |
| 137 | */ |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 138 | union { |
| 139 | struct page *pages[DIO_PAGES]; /* page buffer */ |
| 140 | struct work_struct complete_work;/* deferred AIO completion */ |
| 141 | }; |
Andi Kleen | 6e8267f | 2011-08-01 21:38:06 -0700 | [diff] [blame] | 142 | } ____cacheline_aligned_in_smp; |
| 143 | |
| 144 | static struct kmem_cache *dio_cache __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | |
| 146 | /* |
| 147 | * How many pages are in the queue? |
| 148 | */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 149 | static inline unsigned dio_pages_present(struct dio_submit *sdio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | { |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 151 | return sdio->tail - sdio->head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | } |
| 153 | |
| 154 | /* |
| 155 | * Go grab and pin some userspace pages. Typically we'll get 64 at a time. |
| 156 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 157 | static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | { |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 159 | ssize_t ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 161 | ret = iov_iter_get_pages(sdio->iter, dio->pages, DIO_PAGES * PAGE_SIZE, |
| 162 | &sdio->from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 163 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 164 | if (ret < 0 && sdio->blocks_available && (dio->rw & WRITE)) { |
Nick Piggin | 557ed1f | 2007-10-16 01:24:40 -0700 | [diff] [blame] | 165 | struct page *page = ZERO_PAGE(0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | /* |
| 167 | * A memory fault, but the filesystem has some outstanding |
| 168 | * mapped blocks. We need to use those blocks up to avoid |
| 169 | * leaking stale data in the file. |
| 170 | */ |
| 171 | if (dio->page_errors == 0) |
| 172 | dio->page_errors = ret; |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 173 | page_cache_get(page); |
| 174 | dio->pages[0] = page; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 175 | sdio->head = 0; |
| 176 | sdio->tail = 1; |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 177 | sdio->from = 0; |
| 178 | sdio->to = PAGE_SIZE; |
| 179 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 180 | } |
| 181 | |
| 182 | if (ret >= 0) { |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 183 | iov_iter_advance(sdio->iter, ret); |
| 184 | ret += sdio->from; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 185 | sdio->head = 0; |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 186 | sdio->tail = (ret + PAGE_SIZE - 1) / PAGE_SIZE; |
| 187 | sdio->to = ((ret - 1) & (PAGE_SIZE - 1)) + 1; |
| 188 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | return ret; |
| 191 | } |
| 192 | |
| 193 | /* |
| 194 | * Get another userspace page. Returns an ERR_PTR on error. Pages are |
| 195 | * buffered inside the dio so that we can call get_user_pages() against a |
| 196 | * decent number of pages, less frequently. To provide nicer use of the |
| 197 | * L1 cache. |
| 198 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 199 | static inline struct page *dio_get_page(struct dio *dio, |
Boaz Harrosh | 6fcc542 | 2014-07-20 12:09:04 +0300 | [diff] [blame] | 200 | struct dio_submit *sdio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | { |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 202 | if (dio_pages_present(sdio) == 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | int ret; |
| 204 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 205 | ret = dio_refill_pages(dio, sdio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | if (ret) |
| 207 | return ERR_PTR(ret); |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 208 | BUG_ON(dio_pages_present(sdio) == 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | } |
Boaz Harrosh | 6fcc542 | 2014-07-20 12:09:04 +0300 | [diff] [blame] | 210 | return dio->pages[sdio->head]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | } |
| 212 | |
Zach Brown | 6d544bb | 2006-12-10 02:20:54 -0800 | [diff] [blame] | 213 | /** |
| 214 | * dio_complete() - called when all DIO BIO I/O has been completed |
| 215 | * @offset: the byte offset in the file of the completed operation |
| 216 | * |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 217 | * This drops i_dio_count, lets interested parties know that a DIO operation |
| 218 | * has completed, and calculates the resulting return code for the operation. |
Zach Brown | 6d544bb | 2006-12-10 02:20:54 -0800 | [diff] [blame] | 219 | * |
| 220 | * It lets the filesystem know if it registered an interest earlier via |
| 221 | * get_block. Pass the private field of the map buffer_head so that |
| 222 | * filesystems can use it to hold additional state between get_block calls and |
| 223 | * dio_complete. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | */ |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 225 | static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, |
| 226 | bool is_async) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | { |
Zach Brown | 6d544bb | 2006-12-10 02:20:54 -0800 | [diff] [blame] | 228 | ssize_t transferred = 0; |
| 229 | |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 230 | /* |
| 231 | * AIO submission can race with bio completion to get here while |
| 232 | * expecting to have the last io completed by bio completion. |
| 233 | * In that case -EIOCBQUEUED is in fact not an error we want |
| 234 | * to preserve through this call. |
| 235 | */ |
| 236 | if (ret == -EIOCBQUEUED) |
| 237 | ret = 0; |
| 238 | |
Zach Brown | 6d544bb | 2006-12-10 02:20:54 -0800 | [diff] [blame] | 239 | if (dio->result) { |
| 240 | transferred = dio->result; |
| 241 | |
| 242 | /* Check for short read case */ |
| 243 | if ((dio->rw == READ) && ((offset + transferred) > dio->i_size)) |
| 244 | transferred = dio->i_size - offset; |
| 245 | } |
| 246 | |
Zach Brown | 6d544bb | 2006-12-10 02:20:54 -0800 | [diff] [blame] | 247 | if (ret == 0) |
| 248 | ret = dio->page_errors; |
| 249 | if (ret == 0) |
| 250 | ret = dio->io_error; |
| 251 | if (ret == 0) |
| 252 | ret = transferred; |
| 253 | |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 254 | if (dio->end_io && dio->result) |
| 255 | dio->end_io(dio->iocb, offset, transferred, dio->private); |
Christoph Hellwig | 40e2e97 | 2010-07-18 21:17:09 +0000 | [diff] [blame] | 256 | |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 257 | inode_dio_done(dio->inode); |
Christoph Hellwig | 02afc27 | 2013-09-04 15:04:40 +0200 | [diff] [blame] | 258 | if (is_async) { |
| 259 | if (dio->rw & WRITE) { |
| 260 | int err; |
| 261 | |
| 262 | err = generic_write_sync(dio->iocb->ki_filp, offset, |
| 263 | transferred); |
| 264 | if (err < 0 && ret > 0) |
| 265 | ret = err; |
| 266 | } |
| 267 | |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 268 | aio_complete(dio->iocb, ret, 0); |
Christoph Hellwig | 02afc27 | 2013-09-04 15:04:40 +0200 | [diff] [blame] | 269 | } |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 270 | |
| 271 | kmem_cache_free(dio_cache, dio); |
Zach Brown | 6d544bb | 2006-12-10 02:20:54 -0800 | [diff] [blame] | 272 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | } |
| 274 | |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 275 | static void dio_aio_complete_work(struct work_struct *work) |
| 276 | { |
| 277 | struct dio *dio = container_of(work, struct dio, complete_work); |
| 278 | |
| 279 | dio_complete(dio, dio->iocb->ki_pos, 0, true); |
| 280 | } |
| 281 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 282 | static int dio_bio_complete(struct dio *dio, struct bio *bio); |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 283 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | /* |
| 285 | * Asynchronous IO callback. |
| 286 | */ |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 287 | static void dio_bio_end_aio(struct bio *bio, int error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | { |
| 289 | struct dio *dio = bio->bi_private; |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 290 | unsigned long remaining; |
| 291 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | /* cleanup the bio */ |
| 294 | dio_bio_complete(dio, bio); |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 295 | |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 296 | spin_lock_irqsave(&dio->bio_lock, flags); |
| 297 | remaining = --dio->refcount; |
| 298 | if (remaining == 1 && dio->waiter) |
Zach Brown | 20258b2b | 2006-12-10 02:21:01 -0800 | [diff] [blame] | 299 | wake_up_process(dio->waiter); |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 300 | spin_unlock_irqrestore(&dio->bio_lock, flags); |
Zach Brown | 20258b2b | 2006-12-10 02:21:01 -0800 | [diff] [blame] | 301 | |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 302 | if (remaining == 0) { |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 303 | if (dio->result && dio->defer_completion) { |
| 304 | INIT_WORK(&dio->complete_work, dio_aio_complete_work); |
| 305 | queue_work(dio->inode->i_sb->s_dio_done_wq, |
| 306 | &dio->complete_work); |
| 307 | } else { |
| 308 | dio_complete(dio, dio->iocb->ki_pos, 0, true); |
| 309 | } |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 310 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | } |
| 312 | |
| 313 | /* |
| 314 | * The BIO completion handler simply queues the BIO up for the process-context |
| 315 | * handler. |
| 316 | * |
| 317 | * During I/O bi_private points at the dio. After I/O, bi_private is used to |
| 318 | * implement a singly-linked list of completed BIOs, at dio->bio_list. |
| 319 | */ |
NeilBrown | 6712ecf | 2007-09-27 12:47:43 +0200 | [diff] [blame] | 320 | static void dio_bio_end_io(struct bio *bio, int error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | { |
| 322 | struct dio *dio = bio->bi_private; |
| 323 | unsigned long flags; |
| 324 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 325 | spin_lock_irqsave(&dio->bio_lock, flags); |
| 326 | bio->bi_private = dio->bio_list; |
| 327 | dio->bio_list = bio; |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 328 | if (--dio->refcount == 1 && dio->waiter) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | wake_up_process(dio->waiter); |
| 330 | spin_unlock_irqrestore(&dio->bio_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | } |
| 332 | |
Josef Bacik | facd07b | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 333 | /** |
| 334 | * dio_end_io - handle the end io action for the given bio |
| 335 | * @bio: The direct io bio thats being completed |
| 336 | * @error: Error if there was one |
| 337 | * |
| 338 | * This is meant to be called by any filesystem that uses their own dio_submit_t |
| 339 | * so that the DIO specific endio actions are dealt with after the filesystem |
| 340 | * has done it's completion work. |
| 341 | */ |
| 342 | void dio_end_io(struct bio *bio, int error) |
| 343 | { |
| 344 | struct dio *dio = bio->bi_private; |
| 345 | |
| 346 | if (dio->is_async) |
| 347 | dio_bio_end_aio(bio, error); |
| 348 | else |
| 349 | dio_bio_end_io(bio, error); |
| 350 | } |
| 351 | EXPORT_SYMBOL_GPL(dio_end_io); |
| 352 | |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 353 | static inline void |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 354 | dio_bio_alloc(struct dio *dio, struct dio_submit *sdio, |
| 355 | struct block_device *bdev, |
| 356 | sector_t first_sector, int nr_vecs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | { |
| 358 | struct bio *bio; |
| 359 | |
David Dillow | 20d9600 | 2011-01-20 14:44:22 -0800 | [diff] [blame] | 360 | /* |
| 361 | * bio_alloc() is guaranteed to return a bio when called with |
| 362 | * __GFP_WAIT and we request a valid number of vectors. |
| 363 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 364 | bio = bio_alloc(GFP_KERNEL, nr_vecs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 365 | |
| 366 | bio->bi_bdev = bdev; |
Kent Overstreet | 4f024f3 | 2013-10-11 15:44:27 -0700 | [diff] [blame] | 367 | bio->bi_iter.bi_sector = first_sector; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | if (dio->is_async) |
| 369 | bio->bi_end_io = dio_bio_end_aio; |
| 370 | else |
| 371 | bio->bi_end_io = dio_bio_end_io; |
| 372 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 373 | sdio->bio = bio; |
| 374 | sdio->logical_offset_in_bio = sdio->cur_page_fs_offset; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | } |
| 376 | |
| 377 | /* |
| 378 | * In the AIO read case we speculatively dirty the pages before starting IO. |
| 379 | * During IO completion, any of these pages which happen to have been written |
| 380 | * back will be redirtied by bio_check_pages_dirty(). |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 381 | * |
| 382 | * bios hold a dio reference between submit_bio and ->end_io. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 383 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 384 | static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | { |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 386 | struct bio *bio = sdio->bio; |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 387 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | |
| 389 | bio->bi_private = dio; |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 390 | |
| 391 | spin_lock_irqsave(&dio->bio_lock, flags); |
| 392 | dio->refcount++; |
| 393 | spin_unlock_irqrestore(&dio->bio_lock, flags); |
| 394 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 395 | if (dio->is_async && dio->rw == READ) |
| 396 | bio_set_pages_dirty(bio); |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 397 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 398 | if (sdio->submit_io) |
| 399 | sdio->submit_io(dio->rw, bio, dio->inode, |
| 400 | sdio->logical_offset_in_bio); |
Josef Bacik | facd07b | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 401 | else |
| 402 | submit_bio(dio->rw, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 404 | sdio->bio = NULL; |
| 405 | sdio->boundary = 0; |
| 406 | sdio->logical_offset_in_bio = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | } |
| 408 | |
| 409 | /* |
| 410 | * Release any resources in case of a failure |
| 411 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 412 | static inline void dio_cleanup(struct dio *dio, struct dio_submit *sdio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | { |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 414 | while (sdio->head < sdio->tail) |
| 415 | page_cache_release(dio->pages[sdio->head++]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 416 | } |
| 417 | |
| 418 | /* |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 419 | * Wait for the next BIO to complete. Remove it and return it. NULL is |
| 420 | * returned once all BIOs have been completed. This must only be called once |
| 421 | * all bios have been issued so that dio->refcount can only decrease. This |
| 422 | * requires that that the caller hold a reference on the dio. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | */ |
| 424 | static struct bio *dio_await_one(struct dio *dio) |
| 425 | { |
| 426 | unsigned long flags; |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 427 | struct bio *bio = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | |
| 429 | spin_lock_irqsave(&dio->bio_lock, flags); |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 430 | |
| 431 | /* |
| 432 | * Wait as long as the list is empty and there are bios in flight. bio |
| 433 | * completion drops the count, maybe adds to the list, and wakes while |
| 434 | * holding the bio_lock so we don't need set_current_state()'s barrier |
| 435 | * and can call it after testing our condition. |
| 436 | */ |
| 437 | while (dio->refcount > 1 && dio->bio_list == NULL) { |
| 438 | __set_current_state(TASK_UNINTERRUPTIBLE); |
| 439 | dio->waiter = current; |
| 440 | spin_unlock_irqrestore(&dio->bio_lock, flags); |
| 441 | io_schedule(); |
| 442 | /* wake up sets us TASK_RUNNING */ |
| 443 | spin_lock_irqsave(&dio->bio_lock, flags); |
| 444 | dio->waiter = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 445 | } |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 446 | if (dio->bio_list) { |
| 447 | bio = dio->bio_list; |
| 448 | dio->bio_list = bio->bi_private; |
| 449 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | spin_unlock_irqrestore(&dio->bio_lock, flags); |
| 451 | return bio; |
| 452 | } |
| 453 | |
| 454 | /* |
| 455 | * Process one completed BIO. No locks are held. |
| 456 | */ |
| 457 | static int dio_bio_complete(struct dio *dio, struct bio *bio) |
| 458 | { |
| 459 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); |
Kent Overstreet | cb34e05 | 2012-09-05 15:22:02 -0700 | [diff] [blame] | 460 | struct bio_vec *bvec; |
| 461 | unsigned i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | |
| 463 | if (!uptodate) |
Chen, Kenneth W | 174e27c | 2006-03-25 03:08:16 -0800 | [diff] [blame] | 464 | dio->io_error = -EIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | |
| 466 | if (dio->is_async && dio->rw == READ) { |
| 467 | bio_check_pages_dirty(bio); /* transfers ownership */ |
| 468 | } else { |
Kent Overstreet | cb34e05 | 2012-09-05 15:22:02 -0700 | [diff] [blame] | 469 | bio_for_each_segment_all(bvec, bio, i) { |
| 470 | struct page *page = bvec->bv_page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | |
| 472 | if (dio->rw == READ && !PageCompound(page)) |
| 473 | set_page_dirty_lock(page); |
| 474 | page_cache_release(page); |
| 475 | } |
| 476 | bio_put(bio); |
| 477 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | return uptodate ? 0 : -EIO; |
| 479 | } |
| 480 | |
| 481 | /* |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 482 | * Wait on and process all in-flight BIOs. This must only be called once |
| 483 | * all bios have been issued so that the refcount can only decrease. |
| 484 | * This just waits for all bios to make it through dio_bio_complete. IO |
Robert P. J. Day | beb7dd8 | 2007-05-09 07:14:03 +0200 | [diff] [blame] | 485 | * errors are propagated through dio->io_error and should be propagated via |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 486 | * dio_complete(). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | */ |
Zach Brown | 6d544bb | 2006-12-10 02:20:54 -0800 | [diff] [blame] | 488 | static void dio_await_completion(struct dio *dio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | { |
Zach Brown | 0273201 | 2006-12-10 02:20:59 -0800 | [diff] [blame] | 490 | struct bio *bio; |
| 491 | do { |
| 492 | bio = dio_await_one(dio); |
| 493 | if (bio) |
| 494 | dio_bio_complete(dio, bio); |
| 495 | } while (bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 496 | } |
| 497 | |
| 498 | /* |
| 499 | * A really large O_DIRECT read or write can generate a lot of BIOs. So |
| 500 | * to keep the memory consumption sane we periodically reap any completed BIOs |
| 501 | * during the BIO generation phase. |
| 502 | * |
| 503 | * This also helps to limit the peak amount of pinned userspace memory. |
| 504 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 505 | static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 506 | { |
| 507 | int ret = 0; |
| 508 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 509 | if (sdio->reap_counter++ >= 64) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | while (dio->bio_list) { |
| 511 | unsigned long flags; |
| 512 | struct bio *bio; |
| 513 | int ret2; |
| 514 | |
| 515 | spin_lock_irqsave(&dio->bio_lock, flags); |
| 516 | bio = dio->bio_list; |
| 517 | dio->bio_list = bio->bi_private; |
| 518 | spin_unlock_irqrestore(&dio->bio_lock, flags); |
| 519 | ret2 = dio_bio_complete(dio, bio); |
| 520 | if (ret == 0) |
| 521 | ret = ret2; |
| 522 | } |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 523 | sdio->reap_counter = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 524 | } |
| 525 | return ret; |
| 526 | } |
| 527 | |
| 528 | /* |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 529 | * Create workqueue for deferred direct IO completions. We allocate the |
| 530 | * workqueue when it's first needed. This avoids creating workqueue for |
| 531 | * filesystems that don't need it and also allows us to create the workqueue |
| 532 | * late enough so the we can include s_id in the name of the workqueue. |
| 533 | */ |
| 534 | static int sb_init_dio_done_wq(struct super_block *sb) |
| 535 | { |
Olof Johansson | 45150c4 | 2013-09-09 10:34:23 -0700 | [diff] [blame] | 536 | struct workqueue_struct *old; |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 537 | struct workqueue_struct *wq = alloc_workqueue("dio/%s", |
| 538 | WQ_MEM_RECLAIM, 0, |
| 539 | sb->s_id); |
| 540 | if (!wq) |
| 541 | return -ENOMEM; |
| 542 | /* |
| 543 | * This has to be atomic as more DIOs can race to create the workqueue |
| 544 | */ |
Olof Johansson | 45150c4 | 2013-09-09 10:34:23 -0700 | [diff] [blame] | 545 | old = cmpxchg(&sb->s_dio_done_wq, NULL, wq); |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 546 | /* Someone created workqueue before us? Free ours... */ |
Olof Johansson | 45150c4 | 2013-09-09 10:34:23 -0700 | [diff] [blame] | 547 | if (old) |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 548 | destroy_workqueue(wq); |
| 549 | return 0; |
| 550 | } |
| 551 | |
| 552 | static int dio_set_defer_completion(struct dio *dio) |
| 553 | { |
| 554 | struct super_block *sb = dio->inode->i_sb; |
| 555 | |
| 556 | if (dio->defer_completion) |
| 557 | return 0; |
| 558 | dio->defer_completion = true; |
| 559 | if (!sb->s_dio_done_wq) |
| 560 | return sb_init_dio_done_wq(sb); |
| 561 | return 0; |
| 562 | } |
| 563 | |
| 564 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | * Call into the fs to map some more disk blocks. We record the current number |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 566 | * of available blocks at sdio->blocks_available. These are in units of the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | * fs blocksize, (1 << inode->i_blkbits). |
| 568 | * |
| 569 | * The fs is allowed to map lots of blocks at once. If it wants to do that, |
| 570 | * it uses the passed inode-relative block number as the file offset, as usual. |
| 571 | * |
Badari Pulavarty | 1d8fa7a | 2006-03-26 01:38:02 -0800 | [diff] [blame] | 572 | * get_block() is passed the number of i_blkbits-sized blocks which direct_io |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 573 | * has remaining to do. The fs should not map more than this number of blocks. |
| 574 | * |
| 575 | * If the fs has mapped a lot of blocks, it should populate bh->b_size to |
| 576 | * indicate how much contiguous disk space has been made available at |
| 577 | * bh->b_blocknr. |
| 578 | * |
| 579 | * If *any* of the mapped blocks are new, then the fs must set buffer_new(). |
| 580 | * This isn't very efficient... |
| 581 | * |
| 582 | * In the case of filesystem holes: the fs may return an arbitrarily-large |
| 583 | * hole by returning an appropriate value in b_size and by clearing |
| 584 | * buffer_mapped(). However the direct-io code will only process holes one |
Badari Pulavarty | 1d8fa7a | 2006-03-26 01:38:02 -0800 | [diff] [blame] | 585 | * block at a time - it will repeatedly call get_block() as it walks the hole. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 586 | */ |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 587 | static int get_more_blocks(struct dio *dio, struct dio_submit *sdio, |
| 588 | struct buffer_head *map_bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 589 | { |
| 590 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | sector_t fs_startblk; /* Into file, in filesystem-sized blocks */ |
Tao Ma | ae55e1a | 2012-01-12 17:20:33 -0800 | [diff] [blame] | 592 | sector_t fs_endblk; /* Into file, in filesystem-sized blocks */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 593 | unsigned long fs_count; /* Number of filesystem-sized blocks */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 594 | int create; |
Linus Torvalds | ab73857 | 2012-11-29 12:27:00 -0800 | [diff] [blame] | 595 | unsigned int i_blkbits = sdio->blkbits + sdio->blkfactor; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | |
| 597 | /* |
| 598 | * If there was a memory error and we've overwritten all the |
| 599 | * mapped blocks then we can now return that memory error |
| 600 | */ |
| 601 | ret = dio->page_errors; |
| 602 | if (ret == 0) { |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 603 | BUG_ON(sdio->block_in_file >= sdio->final_block_in_request); |
| 604 | fs_startblk = sdio->block_in_file >> sdio->blkfactor; |
Tao Ma | ae55e1a | 2012-01-12 17:20:33 -0800 | [diff] [blame] | 605 | fs_endblk = (sdio->final_block_in_request - 1) >> |
| 606 | sdio->blkfactor; |
| 607 | fs_count = fs_endblk - fs_startblk + 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | |
Nathan Scott | 3c674e7 | 2006-03-29 09:26:15 +1000 | [diff] [blame] | 609 | map_bh->b_state = 0; |
Linus Torvalds | ab73857 | 2012-11-29 12:27:00 -0800 | [diff] [blame] | 610 | map_bh->b_size = fs_count << i_blkbits; |
Nathan Scott | 3c674e7 | 2006-03-29 09:26:15 +1000 | [diff] [blame] | 611 | |
Christoph Hellwig | 5fe878ae | 2009-12-15 16:47:50 -0800 | [diff] [blame] | 612 | /* |
| 613 | * For writes inside i_size on a DIO_SKIP_HOLES filesystem we |
| 614 | * forbid block creations: only overwrites are permitted. |
| 615 | * We will return early to the caller once we see an |
| 616 | * unmapped buffer head returned, and the caller will fall |
| 617 | * back to buffered I/O. |
| 618 | * |
| 619 | * Otherwise the decision is left to the get_blocks method, |
| 620 | * which may decide to handle it or also return an unmapped |
| 621 | * buffer head. |
| 622 | */ |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 623 | create = dio->rw & WRITE; |
Christoph Hellwig | 5fe878ae | 2009-12-15 16:47:50 -0800 | [diff] [blame] | 624 | if (dio->flags & DIO_SKIP_HOLES) { |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 625 | if (sdio->block_in_file < (i_size_read(dio->inode) >> |
| 626 | sdio->blkbits)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 627 | create = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | } |
Nathan Scott | 3c674e7 | 2006-03-29 09:26:15 +1000 | [diff] [blame] | 629 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 630 | ret = (*sdio->get_block)(dio->inode, fs_startblk, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | map_bh, create); |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 632 | |
| 633 | /* Store for completion */ |
| 634 | dio->private = map_bh->b_private; |
Christoph Hellwig | 7b7a866 | 2013-09-04 15:04:39 +0200 | [diff] [blame] | 635 | |
| 636 | if (ret == 0 && buffer_defer_completion(map_bh)) |
| 637 | ret = dio_set_defer_completion(dio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 638 | } |
| 639 | return ret; |
| 640 | } |
| 641 | |
| 642 | /* |
| 643 | * There is no bio. Make one now. |
| 644 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 645 | static inline int dio_new_bio(struct dio *dio, struct dio_submit *sdio, |
| 646 | sector_t start_sector, struct buffer_head *map_bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 647 | { |
| 648 | sector_t sector; |
| 649 | int ret, nr_pages; |
| 650 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 651 | ret = dio_bio_reap(dio, sdio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | if (ret) |
| 653 | goto out; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 654 | sector = start_sector << (sdio->blkbits - 9); |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 655 | nr_pages = min(sdio->pages_in_io, bio_get_nr_vecs(map_bh->b_bdev)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 656 | BUG_ON(nr_pages <= 0); |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 657 | dio_bio_alloc(dio, sdio, map_bh->b_bdev, sector, nr_pages); |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 658 | sdio->boundary = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | out: |
| 660 | return ret; |
| 661 | } |
| 662 | |
| 663 | /* |
| 664 | * Attempt to put the current chunk of 'cur_page' into the current BIO. If |
| 665 | * that was successful then update final_block_in_bio and take a ref against |
| 666 | * the just-added page. |
| 667 | * |
| 668 | * Return zero on success. Non-zero means the caller needs to start a new BIO. |
| 669 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 670 | static inline int dio_bio_add_page(struct dio_submit *sdio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | { |
| 672 | int ret; |
| 673 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 674 | ret = bio_add_page(sdio->bio, sdio->cur_page, |
| 675 | sdio->cur_page_len, sdio->cur_page_offset); |
| 676 | if (ret == sdio->cur_page_len) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | /* |
| 678 | * Decrement count only, if we are done with this page |
| 679 | */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 680 | if ((sdio->cur_page_len + sdio->cur_page_offset) == PAGE_SIZE) |
| 681 | sdio->pages_in_io--; |
| 682 | page_cache_get(sdio->cur_page); |
| 683 | sdio->final_block_in_bio = sdio->cur_page_block + |
| 684 | (sdio->cur_page_len >> sdio->blkbits); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | ret = 0; |
| 686 | } else { |
| 687 | ret = 1; |
| 688 | } |
| 689 | return ret; |
| 690 | } |
| 691 | |
| 692 | /* |
| 693 | * Put cur_page under IO. The section of cur_page which is described by |
| 694 | * cur_page_offset,cur_page_len is put into a BIO. The section of cur_page |
| 695 | * starts on-disk at cur_page_block. |
| 696 | * |
| 697 | * We take a ref against the page here (on behalf of its presence in the bio). |
| 698 | * |
| 699 | * The caller of this function is responsible for removing cur_page from the |
| 700 | * dio, and for dropping the refcount which came from that presence. |
| 701 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 702 | static inline int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio, |
| 703 | struct buffer_head *map_bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | { |
| 705 | int ret = 0; |
| 706 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 707 | if (sdio->bio) { |
| 708 | loff_t cur_offset = sdio->cur_page_fs_offset; |
| 709 | loff_t bio_next_offset = sdio->logical_offset_in_bio + |
Kent Overstreet | 4f024f3 | 2013-10-11 15:44:27 -0700 | [diff] [blame] | 710 | sdio->bio->bi_iter.bi_size; |
Josef Bacik | c2c6ca4 | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 711 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | /* |
Josef Bacik | c2c6ca4 | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 713 | * See whether this new request is contiguous with the old. |
| 714 | * |
Namhyung Kim | f0940ce | 2011-01-11 21:15:03 +0900 | [diff] [blame] | 715 | * Btrfs cannot handle having logically non-contiguous requests |
| 716 | * submitted. For example if you have |
Josef Bacik | c2c6ca4 | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 717 | * |
| 718 | * Logical: [0-4095][HOLE][8192-12287] |
Namhyung Kim | f0940ce | 2011-01-11 21:15:03 +0900 | [diff] [blame] | 719 | * Physical: [0-4095] [4096-8191] |
Josef Bacik | c2c6ca4 | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 720 | * |
| 721 | * We cannot submit those pages together as one BIO. So if our |
| 722 | * current logical offset in the file does not equal what would |
| 723 | * be the next logical offset in the bio, submit the bio we |
| 724 | * have. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 726 | if (sdio->final_block_in_bio != sdio->cur_page_block || |
Josef Bacik | c2c6ca4 | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 727 | cur_offset != bio_next_offset) |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 728 | dio_bio_submit(dio, sdio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | } |
| 730 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 731 | if (sdio->bio == NULL) { |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 732 | ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 | if (ret) |
| 734 | goto out; |
| 735 | } |
| 736 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 737 | if (dio_bio_add_page(sdio) != 0) { |
| 738 | dio_bio_submit(dio, sdio); |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 739 | ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | if (ret == 0) { |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 741 | ret = dio_bio_add_page(sdio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 742 | BUG_ON(ret != 0); |
| 743 | } |
| 744 | } |
| 745 | out: |
| 746 | return ret; |
| 747 | } |
| 748 | |
| 749 | /* |
| 750 | * An autonomous function to put a chunk of a page under deferred IO. |
| 751 | * |
| 752 | * The caller doesn't actually know (or care) whether this piece of page is in |
| 753 | * a BIO, or is under IO or whatever. We just take care of all possible |
| 754 | * situations here. The separation between the logic of do_direct_IO() and |
| 755 | * that of submit_page_section() is important for clarity. Please don't break. |
| 756 | * |
| 757 | * The chunk of page starts on-disk at blocknr. |
| 758 | * |
| 759 | * We perform deferred IO, by recording the last-submitted page inside our |
| 760 | * private part of the dio structure. If possible, we just expand the IO |
| 761 | * across that page here. |
| 762 | * |
| 763 | * If that doesn't work out then we put the old page into the bio and add this |
| 764 | * page to the dio instead. |
| 765 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 766 | static inline int |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 767 | submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page, |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 768 | unsigned offset, unsigned len, sector_t blocknr, |
| 769 | struct buffer_head *map_bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 770 | { |
| 771 | int ret = 0; |
| 772 | |
Andrew Morton | 98c4d57 | 2006-12-10 02:19:47 -0800 | [diff] [blame] | 773 | if (dio->rw & WRITE) { |
| 774 | /* |
| 775 | * Read accounting is performed in submit_bio() |
| 776 | */ |
| 777 | task_io_account_write(len); |
| 778 | } |
| 779 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 780 | /* |
| 781 | * Can we just grow the current page's presence in the dio? |
| 782 | */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 783 | if (sdio->cur_page == page && |
| 784 | sdio->cur_page_offset + sdio->cur_page_len == offset && |
| 785 | sdio->cur_page_block + |
| 786 | (sdio->cur_page_len >> sdio->blkbits) == blocknr) { |
| 787 | sdio->cur_page_len += len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 788 | goto out; |
| 789 | } |
| 790 | |
| 791 | /* |
| 792 | * If there's a deferred page already there then send it. |
| 793 | */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 794 | if (sdio->cur_page) { |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 795 | ret = dio_send_cur_page(dio, sdio, map_bh); |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 796 | page_cache_release(sdio->cur_page); |
| 797 | sdio->cur_page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 798 | if (ret) |
Jan Kara | b1058b9 | 2013-04-29 15:06:18 -0700 | [diff] [blame] | 799 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 800 | } |
| 801 | |
| 802 | page_cache_get(page); /* It is in dio */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 803 | sdio->cur_page = page; |
| 804 | sdio->cur_page_offset = offset; |
| 805 | sdio->cur_page_len = len; |
| 806 | sdio->cur_page_block = blocknr; |
| 807 | sdio->cur_page_fs_offset = sdio->block_in_file << sdio->blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | out: |
Jan Kara | b1058b9 | 2013-04-29 15:06:18 -0700 | [diff] [blame] | 809 | /* |
| 810 | * If sdio->boundary then we want to schedule the IO now to |
| 811 | * avoid metadata seeks. |
| 812 | */ |
| 813 | if (sdio->boundary) { |
| 814 | ret = dio_send_cur_page(dio, sdio, map_bh); |
| 815 | dio_bio_submit(dio, sdio); |
| 816 | page_cache_release(sdio->cur_page); |
| 817 | sdio->cur_page = NULL; |
| 818 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | return ret; |
| 820 | } |
| 821 | |
| 822 | /* |
| 823 | * Clean any dirty buffers in the blockdev mapping which alias newly-created |
| 824 | * file blocks. Only called for S_ISREG files - blockdevs do not set |
| 825 | * buffer_new |
| 826 | */ |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 827 | static void clean_blockdev_aliases(struct dio *dio, struct buffer_head *map_bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | { |
| 829 | unsigned i; |
| 830 | unsigned nblocks; |
| 831 | |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 832 | nblocks = map_bh->b_size >> dio->inode->i_blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 833 | |
| 834 | for (i = 0; i < nblocks; i++) { |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 835 | unmap_underlying_metadata(map_bh->b_bdev, |
| 836 | map_bh->b_blocknr + i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 837 | } |
| 838 | } |
| 839 | |
| 840 | /* |
| 841 | * If we are not writing the entire block and get_block() allocated |
| 842 | * the block for us, we need to fill-in the unused portion of the |
| 843 | * block with zeros. This happens only if user-buffer, fileoffset or |
| 844 | * io length is not filesystem block-size multiple. |
| 845 | * |
| 846 | * `end' is zero if we're doing the start of the IO, 1 at the end of the |
| 847 | * IO. |
| 848 | */ |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 849 | static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio, |
| 850 | int end, struct buffer_head *map_bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | { |
| 852 | unsigned dio_blocks_per_fs_block; |
| 853 | unsigned this_chunk_blocks; /* In dio_blocks */ |
| 854 | unsigned this_chunk_bytes; |
| 855 | struct page *page; |
| 856 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 857 | sdio->start_zero_done = 1; |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 858 | if (!sdio->blkfactor || !buffer_new(map_bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | return; |
| 860 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 861 | dio_blocks_per_fs_block = 1 << sdio->blkfactor; |
| 862 | this_chunk_blocks = sdio->block_in_file & (dio_blocks_per_fs_block - 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | |
| 864 | if (!this_chunk_blocks) |
| 865 | return; |
| 866 | |
| 867 | /* |
| 868 | * We need to zero out part of an fs block. It is either at the |
| 869 | * beginning or the end of the fs block. |
| 870 | */ |
| 871 | if (end) |
| 872 | this_chunk_blocks = dio_blocks_per_fs_block - this_chunk_blocks; |
| 873 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 874 | this_chunk_bytes = this_chunk_blocks << sdio->blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | |
Nick Piggin | 557ed1f | 2007-10-16 01:24:40 -0700 | [diff] [blame] | 876 | page = ZERO_PAGE(0); |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 877 | if (submit_page_section(dio, sdio, page, 0, this_chunk_bytes, |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 878 | sdio->next_block_for_io, map_bh)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 879 | return; |
| 880 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 881 | sdio->next_block_for_io += this_chunk_blocks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 882 | } |
| 883 | |
| 884 | /* |
| 885 | * Walk the user pages, and the file, mapping blocks to disk and generating |
| 886 | * a sequence of (page,offset,len,block) mappings. These mappings are injected |
| 887 | * into submit_page_section(), which takes care of the next stage of submission |
| 888 | * |
| 889 | * Direct IO against a blockdev is different from a file. Because we can |
| 890 | * happily perform page-sized but 512-byte aligned IOs. It is important that |
| 891 | * blockdev IO be able to have fine alignment and large sizes. |
| 892 | * |
Badari Pulavarty | 1d8fa7a | 2006-03-26 01:38:02 -0800 | [diff] [blame] | 893 | * So what we do is to permit the ->get_block function to populate bh.b_size |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 894 | * with the size of IO which is permitted at this offset and this i_blkbits. |
| 895 | * |
| 896 | * For best results, the blockdev should be set up with 512-byte i_blkbits and |
Badari Pulavarty | 1d8fa7a | 2006-03-26 01:38:02 -0800 | [diff] [blame] | 897 | * it should set b_size to PAGE_SIZE or more inside get_block(). This gives |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 898 | * fine alignment but still allows this function to work in PAGE_SIZE units. |
| 899 | */ |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 900 | static int do_direct_IO(struct dio *dio, struct dio_submit *sdio, |
| 901 | struct buffer_head *map_bh) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | { |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 903 | const unsigned blkbits = sdio->blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 904 | int ret = 0; |
| 905 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 906 | while (sdio->block_in_file < sdio->final_block_in_request) { |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 907 | struct page *page; |
| 908 | size_t from, to; |
Boaz Harrosh | 6fcc542 | 2014-07-20 12:09:04 +0300 | [diff] [blame] | 909 | |
| 910 | page = dio_get_page(dio, sdio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 911 | if (IS_ERR(page)) { |
| 912 | ret = PTR_ERR(page); |
| 913 | goto out; |
| 914 | } |
Boaz Harrosh | 6fcc542 | 2014-07-20 12:09:04 +0300 | [diff] [blame] | 915 | from = sdio->head ? 0 : sdio->from; |
| 916 | to = (sdio->head == sdio->tail - 1) ? sdio->to : PAGE_SIZE; |
| 917 | sdio->head++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 918 | |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 919 | while (from < to) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | unsigned this_chunk_bytes; /* # of bytes mapped */ |
| 921 | unsigned this_chunk_blocks; /* # of blocks */ |
| 922 | unsigned u; |
| 923 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 924 | if (sdio->blocks_available == 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 925 | /* |
| 926 | * Need to go and map some more disk |
| 927 | */ |
| 928 | unsigned long blkmask; |
| 929 | unsigned long dio_remainder; |
| 930 | |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 931 | ret = get_more_blocks(dio, sdio, map_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 932 | if (ret) { |
| 933 | page_cache_release(page); |
| 934 | goto out; |
| 935 | } |
| 936 | if (!buffer_mapped(map_bh)) |
| 937 | goto do_holes; |
| 938 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 939 | sdio->blocks_available = |
| 940 | map_bh->b_size >> sdio->blkbits; |
| 941 | sdio->next_block_for_io = |
| 942 | map_bh->b_blocknr << sdio->blkfactor; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 943 | if (buffer_new(map_bh)) |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 944 | clean_blockdev_aliases(dio, map_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 946 | if (!sdio->blkfactor) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | goto do_holes; |
| 948 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 949 | blkmask = (1 << sdio->blkfactor) - 1; |
| 950 | dio_remainder = (sdio->block_in_file & blkmask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 951 | |
| 952 | /* |
| 953 | * If we are at the start of IO and that IO |
| 954 | * starts partway into a fs-block, |
| 955 | * dio_remainder will be non-zero. If the IO |
| 956 | * is a read then we can simply advance the IO |
| 957 | * cursor to the first block which is to be |
| 958 | * read. But if the IO is a write and the |
| 959 | * block was newly allocated we cannot do that; |
| 960 | * the start of the fs block must be zeroed out |
| 961 | * on-disk |
| 962 | */ |
| 963 | if (!buffer_new(map_bh)) |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 964 | sdio->next_block_for_io += dio_remainder; |
| 965 | sdio->blocks_available -= dio_remainder; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | } |
| 967 | do_holes: |
| 968 | /* Handle holes */ |
| 969 | if (!buffer_mapped(map_bh)) { |
Jeff Moyer | 35dc816 | 2006-02-03 03:04:27 -0800 | [diff] [blame] | 970 | loff_t i_size_aligned; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | |
| 972 | /* AKPM: eargh, -ENOTBLK is a hack */ |
Jens Axboe | b31dc66 | 2006-06-13 08:26:10 +0200 | [diff] [blame] | 973 | if (dio->rw & WRITE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | page_cache_release(page); |
| 975 | return -ENOTBLK; |
| 976 | } |
| 977 | |
Jeff Moyer | 35dc816 | 2006-02-03 03:04:27 -0800 | [diff] [blame] | 978 | /* |
| 979 | * Be sure to account for a partial block as the |
| 980 | * last block in the file |
| 981 | */ |
| 982 | i_size_aligned = ALIGN(i_size_read(dio->inode), |
| 983 | 1 << blkbits); |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 984 | if (sdio->block_in_file >= |
Jeff Moyer | 35dc816 | 2006-02-03 03:04:27 -0800 | [diff] [blame] | 985 | i_size_aligned >> blkbits) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 986 | /* We hit eof */ |
| 987 | page_cache_release(page); |
| 988 | goto out; |
| 989 | } |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 990 | zero_user(page, from, 1 << blkbits); |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 991 | sdio->block_in_file++; |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 992 | from += 1 << blkbits; |
Al Viro | 3320c60b | 2014-03-10 02:30:55 -0400 | [diff] [blame] | 993 | dio->result += 1 << blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 994 | goto next_block; |
| 995 | } |
| 996 | |
| 997 | /* |
| 998 | * If we're performing IO which has an alignment which |
| 999 | * is finer than the underlying fs, go check to see if |
| 1000 | * we must zero out the start of this block. |
| 1001 | */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1002 | if (unlikely(sdio->blkfactor && !sdio->start_zero_done)) |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 1003 | dio_zero_block(dio, sdio, 0, map_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1004 | |
| 1005 | /* |
| 1006 | * Work out, in this_chunk_blocks, how much disk we |
| 1007 | * can add to this page |
| 1008 | */ |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1009 | this_chunk_blocks = sdio->blocks_available; |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 1010 | u = (to - from) >> blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1011 | if (this_chunk_blocks > u) |
| 1012 | this_chunk_blocks = u; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1013 | u = sdio->final_block_in_request - sdio->block_in_file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1014 | if (this_chunk_blocks > u) |
| 1015 | this_chunk_blocks = u; |
| 1016 | this_chunk_bytes = this_chunk_blocks << blkbits; |
| 1017 | BUG_ON(this_chunk_bytes == 0); |
| 1018 | |
Jan Kara | 092c8d4 | 2013-04-29 15:06:17 -0700 | [diff] [blame] | 1019 | if (this_chunk_blocks == sdio->blocks_available) |
| 1020 | sdio->boundary = buffer_boundary(map_bh); |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1021 | ret = submit_page_section(dio, sdio, page, |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 1022 | from, |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1023 | this_chunk_bytes, |
Andi Kleen | 1877264 | 2011-08-01 21:38:07 -0700 | [diff] [blame] | 1024 | sdio->next_block_for_io, |
| 1025 | map_bh); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1026 | if (ret) { |
| 1027 | page_cache_release(page); |
| 1028 | goto out; |
| 1029 | } |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1030 | sdio->next_block_for_io += this_chunk_blocks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1031 | |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1032 | sdio->block_in_file += this_chunk_blocks; |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 1033 | from += this_chunk_bytes; |
| 1034 | dio->result += this_chunk_bytes; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1035 | sdio->blocks_available -= this_chunk_blocks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1036 | next_block: |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1037 | BUG_ON(sdio->block_in_file > sdio->final_block_in_request); |
| 1038 | if (sdio->block_in_file == sdio->final_block_in_request) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1039 | break; |
| 1040 | } |
| 1041 | |
| 1042 | /* Drop the ref which was taken in get_user_pages() */ |
| 1043 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1044 | } |
| 1045 | out: |
| 1046 | return ret; |
| 1047 | } |
| 1048 | |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1049 | static inline int drop_refcount(struct dio *dio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1050 | { |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1051 | int ret2; |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 1052 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1053 | |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 1054 | /* |
| 1055 | * Sync will always be dropping the final ref and completing the |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 1056 | * operation. AIO can if it was a broken operation described above or |
| 1057 | * in fact if all the bios race to complete before we get here. In |
| 1058 | * that case dio_complete() translates the EIOCBQUEUED into the proper |
| 1059 | * return code that the caller will hand to aio_complete(). |
| 1060 | * |
| 1061 | * This is managed by the bio_lock instead of being an atomic_t so that |
| 1062 | * completion paths can drop their ref and use the remaining count to |
| 1063 | * decide to wake the submission path atomically. |
Zach Brown | 8459d86 | 2006-12-10 02:21:05 -0800 | [diff] [blame] | 1064 | */ |
Zach Brown | 5eb6c7a | 2006-12-10 02:21:07 -0800 | [diff] [blame] | 1065 | spin_lock_irqsave(&dio->bio_lock, flags); |
| 1066 | ret2 = --dio->refcount; |
| 1067 | spin_unlock_irqrestore(&dio->bio_lock, flags); |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1068 | return ret2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1069 | } |
| 1070 | |
Christoph Hellwig | eafdc7d | 2010-06-04 11:29:53 +0200 | [diff] [blame] | 1071 | /* |
| 1072 | * This is a library function for use by filesystem drivers. |
| 1073 | * |
| 1074 | * The locking rules are governed by the flags parameter: |
| 1075 | * - if the flags value contains DIO_LOCKING we use a fancy locking |
| 1076 | * scheme for dumb filesystems. |
| 1077 | * For writes this function is called under i_mutex and returns with |
| 1078 | * i_mutex held, for reads, i_mutex is not held on entry, but it is |
| 1079 | * taken and dropped again before returning. |
Christoph Hellwig | eafdc7d | 2010-06-04 11:29:53 +0200 | [diff] [blame] | 1080 | * - if the flags value does NOT contain DIO_LOCKING we don't use any |
| 1081 | * internal locking but rather rely on the filesystem to synchronize |
| 1082 | * direct I/O reads/writes versus each other and truncate. |
Christoph Hellwig | df2d6f2 | 2011-06-24 14:29:46 -0400 | [diff] [blame] | 1083 | * |
| 1084 | * To help with locking against truncate we incremented the i_dio_count |
| 1085 | * counter before starting direct I/O, and decrement it once we are done. |
| 1086 | * Truncate can wait for it to reach zero to provide exclusion. It is |
| 1087 | * expected that filesystem provide exclusion between new direct I/O |
| 1088 | * and truncates. For DIO_LOCKING filesystems this is done by i_mutex, |
| 1089 | * but other filesystems need to take care of this on their own. |
Andi Kleen | ba253fb | 2011-08-01 21:38:08 -0700 | [diff] [blame] | 1090 | * |
| 1091 | * NOTE: if you pass "sdio" to anything by pointer make sure that function |
| 1092 | * is always inlined. Otherwise gcc is unable to split the structure into |
| 1093 | * individual fields and will generate much worse code. This is important |
| 1094 | * for the whole file. |
Christoph Hellwig | eafdc7d | 2010-06-04 11:29:53 +0200 | [diff] [blame] | 1095 | */ |
Andi Kleen | 65dd2aa | 2012-01-12 17:20:35 -0800 | [diff] [blame] | 1096 | static inline ssize_t |
| 1097 | do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, |
Al Viro | 31b1403 | 2014-03-05 01:33:16 -0500 | [diff] [blame] | 1098 | struct block_device *bdev, struct iov_iter *iter, loff_t offset, |
| 1099 | get_block_t get_block, dio_iodone_t end_io, |
Josef Bacik | facd07b | 2010-05-23 11:00:55 -0400 | [diff] [blame] | 1100 | dio_submit_t submit_io, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1101 | { |
Linus Torvalds | ab73857 | 2012-11-29 12:27:00 -0800 | [diff] [blame] | 1102 | unsigned i_blkbits = ACCESS_ONCE(inode->i_blkbits); |
| 1103 | unsigned blkbits = i_blkbits; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1104 | unsigned blocksize_mask = (1 << blkbits) - 1; |
| 1105 | ssize_t retval = -EINVAL; |
Christoph Hellwig | af43647 | 2014-07-30 07:18:48 -0400 | [diff] [blame] | 1106 | size_t count = iov_iter_count(iter); |
| 1107 | loff_t end = offset + count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1108 | struct dio *dio; |
Andi Kleen | eb28be2 | 2011-08-01 21:38:03 -0700 | [diff] [blame] | 1109 | struct dio_submit sdio = { 0, }; |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1110 | struct buffer_head map_bh = { 0, }; |
Fengguang Wu | 647d1e4 | 2012-08-09 15:23:09 +0200 | [diff] [blame] | 1111 | struct blk_plug plug; |
Al Viro | 886a391 | 2014-03-05 13:50:45 -0500 | [diff] [blame] | 1112 | unsigned long align = offset | iov_iter_alignment(iter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | |
| 1114 | if (rw & WRITE) |
Jens Axboe | 721a960 | 2011-03-09 11:56:30 +0100 | [diff] [blame] | 1115 | rw = WRITE_ODIRECT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1116 | |
Andi Kleen | 65dd2aa | 2012-01-12 17:20:35 -0800 | [diff] [blame] | 1117 | /* |
| 1118 | * Avoid references to bdev if not absolutely needed to give |
| 1119 | * the early prefetch in the caller enough time. |
| 1120 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | |
Al Viro | 886a391 | 2014-03-05 13:50:45 -0500 | [diff] [blame] | 1122 | if (align & blocksize_mask) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1123 | if (bdev) |
Andi Kleen | 65dd2aa | 2012-01-12 17:20:35 -0800 | [diff] [blame] | 1124 | blkbits = blksize_bits(bdev_logical_block_size(bdev)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1125 | blocksize_mask = (1 << blkbits) - 1; |
Al Viro | 886a391 | 2014-03-05 13:50:45 -0500 | [diff] [blame] | 1126 | if (align & blocksize_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1127 | goto out; |
| 1128 | } |
| 1129 | |
Christoph Hellwig | f9b5570 | 2011-06-24 14:29:42 -0400 | [diff] [blame] | 1130 | /* watch out for a 0 len io from a tricksy fs */ |
Al Viro | 886a391 | 2014-03-05 13:50:45 -0500 | [diff] [blame] | 1131 | if (rw == READ && !iov_iter_count(iter)) |
Christoph Hellwig | f9b5570 | 2011-06-24 14:29:42 -0400 | [diff] [blame] | 1132 | return 0; |
| 1133 | |
Andi Kleen | 6e8267f | 2011-08-01 21:38:06 -0700 | [diff] [blame] | 1134 | dio = kmem_cache_alloc(dio_cache, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1135 | retval = -ENOMEM; |
| 1136 | if (!dio) |
| 1137 | goto out; |
Jeff Moyer | 23aee09 | 2009-12-15 16:47:49 -0800 | [diff] [blame] | 1138 | /* |
| 1139 | * Believe it or not, zeroing out the page array caused a .5% |
| 1140 | * performance regression in a database benchmark. So, we take |
| 1141 | * care to only zero out what's needed. |
| 1142 | */ |
| 1143 | memset(dio, 0, offsetof(struct dio, pages)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1144 | |
Christoph Hellwig | 5fe878ae | 2009-12-15 16:47:50 -0800 | [diff] [blame] | 1145 | dio->flags = flags; |
| 1146 | if (dio->flags & DIO_LOCKING) { |
Christoph Hellwig | f9b5570 | 2011-06-24 14:29:42 -0400 | [diff] [blame] | 1147 | if (rw == READ) { |
Christoph Hellwig | 5fe878ae | 2009-12-15 16:47:50 -0800 | [diff] [blame] | 1148 | struct address_space *mapping = |
| 1149 | iocb->ki_filp->f_mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1150 | |
Christoph Hellwig | 5fe878ae | 2009-12-15 16:47:50 -0800 | [diff] [blame] | 1151 | /* will be released by direct_io_worker */ |
| 1152 | mutex_lock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | |
| 1154 | retval = filemap_write_and_wait_range(mapping, offset, |
| 1155 | end - 1); |
| 1156 | if (retval) { |
Christoph Hellwig | 5fe878ae | 2009-12-15 16:47:50 -0800 | [diff] [blame] | 1157 | mutex_unlock(&inode->i_mutex); |
Andi Kleen | 6e8267f | 2011-08-01 21:38:06 -0700 | [diff] [blame] | 1158 | kmem_cache_free(dio_cache, dio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1159 | goto out; |
| 1160 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1161 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1162 | } |
| 1163 | |
| 1164 | /* |
Christoph Hellwig | 6039257 | 2014-02-10 10:27:11 +1100 | [diff] [blame] | 1165 | * For file extending writes updating i_size before data writeouts |
| 1166 | * complete can expose uninitialized blocks in dumb filesystems. |
| 1167 | * In that case we need to wait for I/O completion even if asked |
| 1168 | * for an asynchronous write. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1169 | */ |
Christoph Hellwig | 6039257 | 2014-02-10 10:27:11 +1100 | [diff] [blame] | 1170 | if (is_sync_kiocb(iocb)) |
| 1171 | dio->is_async = false; |
| 1172 | else if (!(dio->flags & DIO_ASYNC_EXTEND) && |
| 1173 | (rw & WRITE) && end > i_size_read(inode)) |
| 1174 | dio->is_async = false; |
| 1175 | else |
| 1176 | dio->is_async = true; |
| 1177 | |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1178 | dio->inode = inode; |
| 1179 | dio->rw = rw; |
Christoph Hellwig | 02afc27 | 2013-09-04 15:04:40 +0200 | [diff] [blame] | 1180 | |
| 1181 | /* |
| 1182 | * For AIO O_(D)SYNC writes we need to defer completions to a workqueue |
| 1183 | * so that we can call ->fsync. |
| 1184 | */ |
| 1185 | if (dio->is_async && (rw & WRITE) && |
| 1186 | ((iocb->ki_filp->f_flags & O_DSYNC) || |
| 1187 | IS_SYNC(iocb->ki_filp->f_mapping->host))) { |
| 1188 | retval = dio_set_defer_completion(dio); |
| 1189 | if (retval) { |
| 1190 | /* |
| 1191 | * We grab i_mutex only for reads so we don't have |
| 1192 | * to release it here |
| 1193 | */ |
| 1194 | kmem_cache_free(dio_cache, dio); |
| 1195 | goto out; |
| 1196 | } |
| 1197 | } |
| 1198 | |
| 1199 | /* |
| 1200 | * Will be decremented at I/O completion time. |
| 1201 | */ |
| 1202 | atomic_inc(&inode->i_dio_count); |
| 1203 | |
| 1204 | retval = 0; |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1205 | sdio.blkbits = blkbits; |
Linus Torvalds | ab73857 | 2012-11-29 12:27:00 -0800 | [diff] [blame] | 1206 | sdio.blkfactor = i_blkbits - blkbits; |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1207 | sdio.block_in_file = offset >> blkbits; |
| 1208 | |
| 1209 | sdio.get_block = get_block; |
| 1210 | dio->end_io = end_io; |
| 1211 | sdio.submit_io = submit_io; |
| 1212 | sdio.final_block_in_bio = -1; |
| 1213 | sdio.next_block_for_io = -1; |
| 1214 | |
| 1215 | dio->iocb = iocb; |
| 1216 | dio->i_size = i_size_read(inode); |
| 1217 | |
| 1218 | spin_lock_init(&dio->bio_lock); |
| 1219 | dio->refcount = 1; |
| 1220 | |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 1221 | sdio.iter = iter; |
| 1222 | sdio.final_block_in_request = |
| 1223 | (offset + iov_iter_count(iter)) >> blkbits; |
| 1224 | |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1225 | /* |
| 1226 | * In case of non-aligned buffers, we may need 2 more |
| 1227 | * pages since we need to zero out first and last block. |
| 1228 | */ |
| 1229 | if (unlikely(sdio.blkfactor)) |
| 1230 | sdio.pages_in_io = 2; |
| 1231 | |
Al Viro | f67da30 | 2014-03-19 01:16:16 -0400 | [diff] [blame] | 1232 | sdio.pages_in_io += iov_iter_npages(iter, INT_MAX); |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1233 | |
Fengguang Wu | 647d1e4 | 2012-08-09 15:23:09 +0200 | [diff] [blame] | 1234 | blk_start_plug(&plug); |
| 1235 | |
Al Viro | 7b2c99d | 2014-03-15 04:05:57 -0400 | [diff] [blame] | 1236 | retval = do_direct_IO(dio, &sdio, &map_bh); |
| 1237 | if (retval) |
| 1238 | dio_cleanup(dio, &sdio); |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1239 | |
| 1240 | if (retval == -ENOTBLK) { |
| 1241 | /* |
| 1242 | * The remaining part of the request will be |
| 1243 | * be handled by buffered I/O when we return |
| 1244 | */ |
| 1245 | retval = 0; |
| 1246 | } |
| 1247 | /* |
| 1248 | * There may be some unwritten disk at the end of a part-written |
| 1249 | * fs-block-sized block. Go zero that now. |
| 1250 | */ |
| 1251 | dio_zero_block(dio, &sdio, 1, &map_bh); |
| 1252 | |
| 1253 | if (sdio.cur_page) { |
| 1254 | ssize_t ret2; |
| 1255 | |
| 1256 | ret2 = dio_send_cur_page(dio, &sdio, &map_bh); |
| 1257 | if (retval == 0) |
| 1258 | retval = ret2; |
| 1259 | page_cache_release(sdio.cur_page); |
| 1260 | sdio.cur_page = NULL; |
| 1261 | } |
| 1262 | if (sdio.bio) |
| 1263 | dio_bio_submit(dio, &sdio); |
| 1264 | |
Fengguang Wu | 647d1e4 | 2012-08-09 15:23:09 +0200 | [diff] [blame] | 1265 | blk_finish_plug(&plug); |
| 1266 | |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1267 | /* |
| 1268 | * It is possible that, we return short IO due to end of file. |
| 1269 | * In that case, we need to release all the pages we got hold on. |
| 1270 | */ |
| 1271 | dio_cleanup(dio, &sdio); |
| 1272 | |
| 1273 | /* |
| 1274 | * All block lookups have been performed. For READ requests |
| 1275 | * we can let i_mutex go now that its achieved its purpose |
| 1276 | * of protecting us from looking up uninitialized blocks. |
| 1277 | */ |
| 1278 | if (rw == READ && (dio->flags & DIO_LOCKING)) |
| 1279 | mutex_unlock(&dio->inode->i_mutex); |
| 1280 | |
| 1281 | /* |
| 1282 | * The only time we want to leave bios in flight is when a successful |
| 1283 | * partial aio read or full aio write have been setup. In that case |
| 1284 | * bio completion will call aio_complete. The only time it's safe to |
| 1285 | * call aio_complete is when we return -EIOCBQUEUED, so we key on that. |
| 1286 | * This had *better* be the only place that raises -EIOCBQUEUED. |
| 1287 | */ |
| 1288 | BUG_ON(retval == -EIOCBQUEUED); |
| 1289 | if (dio->is_async && retval == 0 && dio->result && |
Christoph Hellwig | af43647 | 2014-07-30 07:18:48 -0400 | [diff] [blame] | 1290 | (rw == READ || dio->result == count)) |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1291 | retval = -EIOCBQUEUED; |
Christoph Hellwig | af43647 | 2014-07-30 07:18:48 -0400 | [diff] [blame] | 1292 | else |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1293 | dio_await_completion(dio); |
| 1294 | |
| 1295 | if (drop_refcount(dio) == 0) { |
| 1296 | retval = dio_complete(dio, offset, retval, false); |
Andi Kleen | 847cc63 | 2011-08-01 21:38:09 -0700 | [diff] [blame] | 1297 | } else |
| 1298 | BUG_ON(retval != -EIOCBQUEUED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1299 | |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 1300 | out: |
| 1301 | return retval; |
| 1302 | } |
Andi Kleen | 65dd2aa | 2012-01-12 17:20:35 -0800 | [diff] [blame] | 1303 | |
| 1304 | ssize_t |
| 1305 | __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, |
Al Viro | 31b1403 | 2014-03-05 01:33:16 -0500 | [diff] [blame] | 1306 | struct block_device *bdev, struct iov_iter *iter, loff_t offset, |
| 1307 | get_block_t get_block, dio_iodone_t end_io, |
Andi Kleen | 65dd2aa | 2012-01-12 17:20:35 -0800 | [diff] [blame] | 1308 | dio_submit_t submit_io, int flags) |
| 1309 | { |
| 1310 | /* |
| 1311 | * The block device state is needed in the end to finally |
| 1312 | * submit everything. Since it's likely to be cache cold |
| 1313 | * prefetch it here as first thing to hide some of the |
| 1314 | * latency. |
| 1315 | * |
| 1316 | * Attempt to prefetch the pieces we likely need later. |
| 1317 | */ |
| 1318 | prefetch(&bdev->bd_disk->part_tbl); |
| 1319 | prefetch(bdev->bd_queue); |
| 1320 | prefetch((char *)bdev->bd_queue + SMP_CACHE_BYTES); |
| 1321 | |
Al Viro | 31b1403 | 2014-03-05 01:33:16 -0500 | [diff] [blame] | 1322 | return do_blockdev_direct_IO(rw, iocb, inode, bdev, iter, offset, |
| 1323 | get_block, end_io, submit_io, flags); |
Andi Kleen | 65dd2aa | 2012-01-12 17:20:35 -0800 | [diff] [blame] | 1324 | } |
| 1325 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1326 | EXPORT_SYMBOL(__blockdev_direct_IO); |
Andi Kleen | 6e8267f | 2011-08-01 21:38:06 -0700 | [diff] [blame] | 1327 | |
| 1328 | static __init int dio_init(void) |
| 1329 | { |
| 1330 | dio_cache = KMEM_CACHE(dio, SLAB_PANIC); |
| 1331 | return 0; |
| 1332 | } |
| 1333 | module_init(dio_init) |