Thomas Gleixner | 457c899 | 2019-05-19 13:08:55 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * fs/libfs.c |
| 4 | * Library for filesystems writers. |
| 5 | */ |
| 6 | |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 7 | #include <linux/blkdev.h> |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 8 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | #include <linux/pagemap.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 10 | #include <linux/slab.h> |
Ingo Molnar | 5b825c3 | 2017-02-02 17:54:15 +0100 | [diff] [blame] | 11 | #include <linux/cred.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/mount.h> |
| 13 | #include <linux/vfs.h> |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 14 | #include <linux/quotaops.h> |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 15 | #include <linux/mutex.h> |
Al Viro | 87dc800 | 2013-09-16 10:30:04 -0400 | [diff] [blame] | 16 | #include <linux/namei.h> |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 17 | #include <linux/exportfs.h> |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 18 | #include <linux/writeback.h> |
Al Viro | ff01bb4 | 2011-09-16 02:31:11 -0400 | [diff] [blame] | 19 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 20 | #include <linux/fs_context.h> |
| 21 | #include <linux/pseudo_fs.h> |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 22 | #include <linux/fsnotify.h> |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 23 | #include <linux/unicode.h> |
| 24 | #include <linux/fscrypt.h> |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 25 | |
Linus Torvalds | 7c0f6ba | 2016-12-24 11:46:01 -0800 | [diff] [blame] | 26 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 28 | #include "internal.h" |
| 29 | |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 30 | int simple_getattr(const struct path *path, struct kstat *stat, |
| 31 | u32 request_mask, unsigned int query_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | { |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 33 | struct inode *inode = d_inode(path->dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | generic_fillattr(inode, stat); |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 35 | stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | return 0; |
| 37 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 38 | EXPORT_SYMBOL(simple_getattr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 40 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | { |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 42 | buf->f_type = dentry->d_sb->s_magic; |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 43 | buf->f_bsize = PAGE_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | buf->f_namelen = NAME_MAX; |
| 45 | return 0; |
| 46 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 47 | EXPORT_SYMBOL(simple_statfs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | |
| 49 | /* |
| 50 | * Retaining negative dentries for an in-memory filesystem just wastes |
| 51 | * memory and lookup time: arrange for them to be deleted immediately. |
| 52 | */ |
Al Viro | b26d4cd | 2013-10-25 18:47:37 -0400 | [diff] [blame] | 53 | int always_delete_dentry(const struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | { |
| 55 | return 1; |
| 56 | } |
Al Viro | b26d4cd | 2013-10-25 18:47:37 -0400 | [diff] [blame] | 57 | EXPORT_SYMBOL(always_delete_dentry); |
| 58 | |
| 59 | const struct dentry_operations simple_dentry_operations = { |
| 60 | .d_delete = always_delete_dentry, |
| 61 | }; |
| 62 | EXPORT_SYMBOL(simple_dentry_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
| 64 | /* |
| 65 | * Lookup the data. This is trivial - if the dentry didn't already |
| 66 | * exist, we know it is negative. Set d_op to delete negative dentries. |
| 67 | */ |
Al Viro | 00cd8dd | 2012-06-10 17:13:09 -0400 | [diff] [blame] | 68 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | if (dentry->d_name.len > NAME_MAX) |
| 71 | return ERR_PTR(-ENAMETOOLONG); |
Al Viro | 74931da | 2013-07-14 17:43:25 +0400 | [diff] [blame] | 72 | if (!dentry->d_sb->s_d_op) |
| 73 | d_set_d_op(dentry, &simple_dentry_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | d_add(dentry, NULL); |
| 75 | return NULL; |
| 76 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 77 | EXPORT_SYMBOL(simple_lookup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | int dcache_dir_open(struct inode *inode, struct file *file) |
| 80 | { |
Al Viro | ba65dc5 | 2016-06-10 11:32:47 -0400 | [diff] [blame] | 81 | file->private_data = d_alloc_cursor(file->f_path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
| 83 | return file->private_data ? 0 : -ENOMEM; |
| 84 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 85 | EXPORT_SYMBOL(dcache_dir_open); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | |
| 87 | int dcache_dir_close(struct inode *inode, struct file *file) |
| 88 | { |
| 89 | dput(file->private_data); |
| 90 | return 0; |
| 91 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 92 | EXPORT_SYMBOL(dcache_dir_close); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 94 | /* parent is locked at least shared */ |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 95 | /* |
| 96 | * Returns an element of siblings' list. |
| 97 | * We are looking for <count>th positive after <p>; if |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 98 | * found, dentry is grabbed and returned to caller. |
| 99 | * If no such element exists, NULL is returned. |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 100 | */ |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 101 | static struct dentry *scan_positives(struct dentry *cursor, |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 102 | struct list_head *p, |
| 103 | loff_t count, |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 104 | struct dentry *last) |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 105 | { |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 106 | struct dentry *dentry = cursor->d_parent, *found = NULL; |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 107 | |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 108 | spin_lock(&dentry->d_lock); |
| 109 | while ((p = p->next) != &dentry->d_subdirs) { |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 110 | struct dentry *d = list_entry(p, struct dentry, d_child); |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 111 | // we must at least skip cursors, to avoid livelocks |
| 112 | if (d->d_flags & DCACHE_DENTRY_CURSOR) |
| 113 | continue; |
| 114 | if (simple_positive(d) && !--count) { |
| 115 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); |
| 116 | if (simple_positive(d)) |
| 117 | found = dget_dlock(d); |
| 118 | spin_unlock(&d->d_lock); |
| 119 | if (likely(found)) |
| 120 | break; |
| 121 | count = 1; |
| 122 | } |
| 123 | if (need_resched()) { |
| 124 | list_move(&cursor->d_child, p); |
| 125 | p = &cursor->d_child; |
| 126 | spin_unlock(&dentry->d_lock); |
| 127 | cond_resched(); |
| 128 | spin_lock(&dentry->d_lock); |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 129 | } |
| 130 | } |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 131 | spin_unlock(&dentry->d_lock); |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 132 | dput(last); |
| 133 | return found; |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 134 | } |
| 135 | |
Andrew Morton | 965c8e5 | 2012-12-17 15:59:39 -0800 | [diff] [blame] | 136 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 138 | struct dentry *dentry = file->f_path.dentry; |
Andrew Morton | 965c8e5 | 2012-12-17 15:59:39 -0800 | [diff] [blame] | 139 | switch (whence) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | case 1: |
| 141 | offset += file->f_pos; |
Gustavo A. R. Silva | df561f66 | 2020-08-23 17:36:59 -0500 | [diff] [blame] | 142 | fallthrough; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | case 0: |
| 144 | if (offset >= 0) |
| 145 | break; |
Gustavo A. R. Silva | df561f66 | 2020-08-23 17:36:59 -0500 | [diff] [blame] | 146 | fallthrough; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | default: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | return -EINVAL; |
| 149 | } |
| 150 | if (offset != file->f_pos) { |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 151 | struct dentry *cursor = file->private_data; |
| 152 | struct dentry *to = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 154 | inode_lock_shared(dentry->d_inode); |
| 155 | |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 156 | if (offset > 2) |
| 157 | to = scan_positives(cursor, &dentry->d_subdirs, |
| 158 | offset - 2, NULL); |
| 159 | spin_lock(&dentry->d_lock); |
| 160 | if (to) |
| 161 | list_move(&cursor->d_child, &to->d_child); |
| 162 | else |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 163 | list_del_init(&cursor->d_child); |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 164 | spin_unlock(&dentry->d_lock); |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 165 | dput(to); |
| 166 | |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 167 | file->f_pos = offset; |
| 168 | |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 169 | inode_unlock_shared(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | return offset; |
| 172 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 173 | EXPORT_SYMBOL(dcache_dir_lseek); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | |
| 175 | /* Relationship between i_mode and the DT_xxx types */ |
| 176 | static inline unsigned char dt_type(struct inode *inode) |
| 177 | { |
| 178 | return (inode->i_mode >> 12) & 15; |
| 179 | } |
| 180 | |
| 181 | /* |
| 182 | * Directory is locked and all positive dentries in it are safe, since |
| 183 | * for ramfs-type trees they can't go away without unlink() or rmdir(), |
| 184 | * both impossible due to the lock on directory. |
| 185 | */ |
| 186 | |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 187 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | { |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 189 | struct dentry *dentry = file->f_path.dentry; |
| 190 | struct dentry *cursor = file->private_data; |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 191 | struct list_head *anchor = &dentry->d_subdirs; |
| 192 | struct dentry *next = NULL; |
| 193 | struct list_head *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 194 | |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 195 | if (!dir_emit_dots(file, ctx)) |
| 196 | return 0; |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 197 | |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 198 | if (ctx->pos == 2) |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 199 | p = anchor; |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 200 | else if (!list_empty(&cursor->d_child)) |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 201 | p = &cursor->d_child; |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 202 | else |
| 203 | return 0; |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 204 | |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 205 | while ((next = scan_positives(cursor, p, 1, next)) != NULL) { |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 206 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 207 | d_inode(next)->i_ino, dt_type(d_inode(next)))) |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 208 | break; |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 209 | ctx->pos++; |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 210 | p = &next->d_child; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | } |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 212 | spin_lock(&dentry->d_lock); |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 213 | if (next) |
| 214 | list_move_tail(&cursor->d_child, &next->d_child); |
| 215 | else |
| 216 | list_del_init(&cursor->d_child); |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 217 | spin_unlock(&dentry->d_lock); |
| 218 | dput(next); |
| 219 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | return 0; |
| 221 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 222 | EXPORT_SYMBOL(dcache_readdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | |
| 224 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) |
| 225 | { |
| 226 | return -EISDIR; |
| 227 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 228 | EXPORT_SYMBOL(generic_read_dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 230 | const struct file_operations simple_dir_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 231 | .open = dcache_dir_open, |
| 232 | .release = dcache_dir_close, |
| 233 | .llseek = dcache_dir_lseek, |
| 234 | .read = generic_read_dir, |
Al Viro | 4e82901 | 2016-04-20 19:52:15 -0400 | [diff] [blame] | 235 | .iterate_shared = dcache_readdir, |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 236 | .fsync = noop_fsync, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | }; |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 238 | EXPORT_SYMBOL(simple_dir_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 240 | const struct inode_operations simple_dir_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | .lookup = simple_lookup, |
| 242 | }; |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 243 | EXPORT_SYMBOL(simple_dir_inode_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 245 | static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev) |
| 246 | { |
| 247 | struct dentry *child = NULL; |
| 248 | struct list_head *p = prev ? &prev->d_child : &parent->d_subdirs; |
| 249 | |
| 250 | spin_lock(&parent->d_lock); |
| 251 | while ((p = p->next) != &parent->d_subdirs) { |
| 252 | struct dentry *d = container_of(p, struct dentry, d_child); |
| 253 | if (simple_positive(d)) { |
| 254 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); |
| 255 | if (simple_positive(d)) |
| 256 | child = dget_dlock(d); |
| 257 | spin_unlock(&d->d_lock); |
| 258 | if (likely(child)) |
| 259 | break; |
| 260 | } |
| 261 | } |
| 262 | spin_unlock(&parent->d_lock); |
| 263 | dput(prev); |
| 264 | return child; |
| 265 | } |
| 266 | |
| 267 | void simple_recursive_removal(struct dentry *dentry, |
| 268 | void (*callback)(struct dentry *)) |
| 269 | { |
| 270 | struct dentry *this = dget(dentry); |
| 271 | while (true) { |
| 272 | struct dentry *victim = NULL, *child; |
| 273 | struct inode *inode = this->d_inode; |
| 274 | |
| 275 | inode_lock(inode); |
| 276 | if (d_is_dir(this)) |
| 277 | inode->i_flags |= S_DEAD; |
| 278 | while ((child = find_next_child(this, victim)) == NULL) { |
| 279 | // kill and ascend |
| 280 | // update metadata while it's still locked |
| 281 | inode->i_ctime = current_time(inode); |
| 282 | clear_nlink(inode); |
| 283 | inode_unlock(inode); |
| 284 | victim = this; |
| 285 | this = this->d_parent; |
| 286 | inode = this->d_inode; |
| 287 | inode_lock(inode); |
| 288 | if (simple_positive(victim)) { |
| 289 | d_invalidate(victim); // avoid lost mounts |
| 290 | if (d_is_dir(victim)) |
| 291 | fsnotify_rmdir(inode, victim); |
| 292 | else |
| 293 | fsnotify_unlink(inode, victim); |
| 294 | if (callback) |
| 295 | callback(victim); |
| 296 | dput(victim); // unpin it |
| 297 | } |
| 298 | if (victim == dentry) { |
| 299 | inode->i_ctime = inode->i_mtime = |
| 300 | current_time(inode); |
| 301 | if (d_is_dir(dentry)) |
| 302 | drop_nlink(inode); |
| 303 | inode_unlock(inode); |
| 304 | dput(dentry); |
| 305 | return; |
| 306 | } |
| 307 | } |
| 308 | inode_unlock(inode); |
| 309 | this = child; |
| 310 | } |
| 311 | } |
| 312 | EXPORT_SYMBOL(simple_recursive_removal); |
| 313 | |
Hugh Dickins | 759b977 | 2007-03-05 00:30:28 -0800 | [diff] [blame] | 314 | static const struct super_operations simple_super_operations = { |
| 315 | .statfs = simple_statfs, |
| 316 | }; |
| 317 | |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 318 | static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | { |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 320 | struct pseudo_fs_context *ctx = fc->fs_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | struct inode *root; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | |
Jeff Layton | 89a4eb4 | 2009-08-18 14:11:08 -0700 | [diff] [blame] | 323 | s->s_maxbytes = MAX_LFS_FILESIZE; |
Alex Nixon | 3971e1a | 2008-07-29 22:33:03 -0700 | [diff] [blame] | 324 | s->s_blocksize = PAGE_SIZE; |
| 325 | s->s_blocksize_bits = PAGE_SHIFT; |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 326 | s->s_magic = ctx->magic; |
| 327 | s->s_op = ctx->ops ?: &simple_super_operations; |
| 328 | s->s_xattr = ctx->xattr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | s->s_time_gran = 1; |
| 330 | root = new_inode(s); |
| 331 | if (!root) |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 332 | return -ENOMEM; |
| 333 | |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 334 | /* |
| 335 | * since this is the first inode, make it number 1. New inodes created |
| 336 | * after this must take care not to collide with it (by passing |
| 337 | * max_reserved of 1 to iunique). |
| 338 | */ |
| 339 | root->i_ino = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 341 | root->i_atime = root->i_mtime = root->i_ctime = current_time(root); |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 342 | s->s_root = d_make_root(root); |
| 343 | if (!s->s_root) |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 344 | return -ENOMEM; |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 345 | s->s_d_op = ctx->dops; |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 346 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | } |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 348 | |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 349 | static int pseudo_fs_get_tree(struct fs_context *fc) |
| 350 | { |
Al Viro | 2ac295d | 2019-06-01 20:48:55 -0400 | [diff] [blame] | 351 | return get_tree_nodev(fc, pseudo_fs_fill_super); |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 352 | } |
| 353 | |
| 354 | static void pseudo_fs_free(struct fs_context *fc) |
| 355 | { |
| 356 | kfree(fc->fs_private); |
| 357 | } |
| 358 | |
| 359 | static const struct fs_context_operations pseudo_fs_context_ops = { |
| 360 | .free = pseudo_fs_free, |
| 361 | .get_tree = pseudo_fs_get_tree, |
| 362 | }; |
| 363 | |
| 364 | /* |
| 365 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that |
| 366 | * will never be mountable) |
| 367 | */ |
| 368 | struct pseudo_fs_context *init_pseudo(struct fs_context *fc, |
| 369 | unsigned long magic) |
| 370 | { |
| 371 | struct pseudo_fs_context *ctx; |
| 372 | |
| 373 | ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL); |
| 374 | if (likely(ctx)) { |
| 375 | ctx->magic = magic; |
| 376 | fc->fs_private = ctx; |
| 377 | fc->ops = &pseudo_fs_context_ops; |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 378 | fc->sb_flags |= SB_NOUSER; |
| 379 | fc->global = true; |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 380 | } |
| 381 | return ctx; |
| 382 | } |
| 383 | EXPORT_SYMBOL(init_pseudo); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | |
Stephen Boyd | 20955e8 | 2012-04-05 14:25:09 -0700 | [diff] [blame] | 385 | int simple_open(struct inode *inode, struct file *file) |
| 386 | { |
| 387 | if (inode->i_private) |
| 388 | file->private_data = inode->i_private; |
| 389 | return 0; |
| 390 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 391 | EXPORT_SYMBOL(simple_open); |
Stephen Boyd | 20955e8 | 2012-04-05 14:25:09 -0700 | [diff] [blame] | 392 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
| 394 | { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 395 | struct inode *inode = d_inode(old_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 397 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 398 | inc_nlink(inode); |
Al Viro | 7de9c6ee | 2010-10-23 11:11:40 -0400 | [diff] [blame] | 399 | ihold(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | dget(dentry); |
| 401 | d_instantiate(dentry, inode); |
| 402 | return 0; |
| 403 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 404 | EXPORT_SYMBOL(simple_link); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | int simple_empty(struct dentry *dentry) |
| 407 | { |
| 408 | struct dentry *child; |
| 409 | int ret = 0; |
| 410 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 411 | spin_lock(&dentry->d_lock); |
Al Viro | 946e51f | 2014-10-26 19:19:16 -0400 | [diff] [blame] | 412 | list_for_each_entry(child, &dentry->d_subdirs, d_child) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 413 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
| 414 | if (simple_positive(child)) { |
| 415 | spin_unlock(&child->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 416 | goto out; |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 417 | } |
| 418 | spin_unlock(&child->d_lock); |
| 419 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | ret = 1; |
| 421 | out: |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 422 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | return ret; |
| 424 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 425 | EXPORT_SYMBOL(simple_empty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | |
| 427 | int simple_unlink(struct inode *dir, struct dentry *dentry) |
| 428 | { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 429 | struct inode *inode = d_inode(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 431 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 432 | drop_nlink(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | dput(dentry); |
| 434 | return 0; |
| 435 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 436 | EXPORT_SYMBOL(simple_unlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 437 | |
| 438 | int simple_rmdir(struct inode *dir, struct dentry *dentry) |
| 439 | { |
| 440 | if (!simple_empty(dentry)) |
| 441 | return -ENOTEMPTY; |
| 442 | |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 443 | drop_nlink(d_inode(dentry)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | simple_unlink(dir, dentry); |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 445 | drop_nlink(dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | return 0; |
| 447 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 448 | EXPORT_SYMBOL(simple_rmdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | |
| 450 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, |
Miklos Szeredi | e0e0be8 | 2016-09-27 11:03:57 +0200 | [diff] [blame] | 451 | struct inode *new_dir, struct dentry *new_dentry, |
| 452 | unsigned int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 454 | struct inode *inode = d_inode(old_dentry); |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 455 | int they_are_dirs = d_is_dir(old_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | |
Miklos Szeredi | e0e0be8 | 2016-09-27 11:03:57 +0200 | [diff] [blame] | 457 | if (flags & ~RENAME_NOREPLACE) |
| 458 | return -EINVAL; |
| 459 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | if (!simple_empty(new_dentry)) |
| 461 | return -ENOTEMPTY; |
| 462 | |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 463 | if (d_really_is_positive(new_dentry)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | simple_unlink(new_dir, new_dentry); |
Al Viro | 841590c | 2011-07-21 15:49:09 -0400 | [diff] [blame] | 465 | if (they_are_dirs) { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 466 | drop_nlink(d_inode(new_dentry)); |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 467 | drop_nlink(old_dir); |
Al Viro | 841590c | 2011-07-21 15:49:09 -0400 | [diff] [blame] | 468 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | } else if (they_are_dirs) { |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 470 | drop_nlink(old_dir); |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 471 | inc_nlink(new_dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | } |
| 473 | |
| 474 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 475 | new_dir->i_mtime = inode->i_ctime = current_time(old_dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | |
| 477 | return 0; |
| 478 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 479 | EXPORT_SYMBOL(simple_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 481 | /** |
Christoph Hellwig | eef2380 | 2010-06-04 11:30:01 +0200 | [diff] [blame] | 482 | * simple_setattr - setattr for simple filesystem |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 483 | * @dentry: dentry |
| 484 | * @iattr: iattr structure |
| 485 | * |
| 486 | * Returns 0 on success, -error on failure. |
| 487 | * |
Christoph Hellwig | eef2380 | 2010-06-04 11:30:01 +0200 | [diff] [blame] | 488 | * simple_setattr is a simple ->setattr implementation without a proper |
| 489 | * implementation of size changes. |
| 490 | * |
| 491 | * It can either be used for in-memory filesystems or special files |
| 492 | * on simple regular filesystems. Anything that needs to change on-disk |
| 493 | * or wire state on size changes needs its own setattr method. |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 494 | */ |
| 495 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) |
| 496 | { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 497 | struct inode *inode = d_inode(dentry); |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 498 | int error; |
| 499 | |
Jan Kara | 31051c8 | 2016-05-26 16:55:18 +0200 | [diff] [blame] | 500 | error = setattr_prepare(dentry, iattr); |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 501 | if (error) |
| 502 | return error; |
| 503 | |
Christoph Hellwig | 2c27c65 | 2010-06-04 11:30:04 +0200 | [diff] [blame] | 504 | if (iattr->ia_valid & ATTR_SIZE) |
| 505 | truncate_setsize(inode, iattr->ia_size); |
Christoph Hellwig | 6a1a90a | 2010-06-04 11:30:00 +0200 | [diff] [blame] | 506 | setattr_copy(inode, iattr); |
Christoph Hellwig | eef2380 | 2010-06-04 11:30:01 +0200 | [diff] [blame] | 507 | mark_inode_dirty(inode); |
| 508 | return 0; |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 509 | } |
| 510 | EXPORT_SYMBOL(simple_setattr); |
| 511 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | int simple_readpage(struct file *file, struct page *page) |
| 513 | { |
Pekka J Enberg | c0d92cb | 2006-09-29 01:59:09 -0700 | [diff] [blame] | 514 | clear_highpage(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | flush_dcache_page(page); |
| 516 | SetPageUptodate(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 517 | unlock_page(page); |
| 518 | return 0; |
| 519 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 520 | EXPORT_SYMBOL(simple_readpage); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 522 | int simple_write_begin(struct file *file, struct address_space *mapping, |
| 523 | loff_t pos, unsigned len, unsigned flags, |
| 524 | struct page **pagep, void **fsdata) |
| 525 | { |
| 526 | struct page *page; |
| 527 | pgoff_t index; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 528 | |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 529 | index = pos >> PAGE_SHIFT; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 530 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 531 | page = grab_cache_page_write_begin(mapping, index, flags); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 532 | if (!page) |
| 533 | return -ENOMEM; |
| 534 | |
| 535 | *pagep = page; |
| 536 | |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 537 | if (!PageUptodate(page) && (len != PAGE_SIZE)) { |
| 538 | unsigned from = pos & (PAGE_SIZE - 1); |
Boaz Harrosh | 193cf4b | 2010-01-12 16:18:08 +0200 | [diff] [blame] | 539 | |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 540 | zero_user_segments(page, 0, from, from + len, PAGE_SIZE); |
Boaz Harrosh | 193cf4b | 2010-01-12 16:18:08 +0200 | [diff] [blame] | 541 | } |
| 542 | return 0; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 543 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 544 | EXPORT_SYMBOL(simple_write_begin); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 545 | |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 546 | /** |
| 547 | * simple_write_end - .write_end helper for non-block-device FSes |
Randy Dunlap | 8e88bfb | 2019-10-14 14:12:14 -0700 | [diff] [blame] | 548 | * @file: See .write_end of address_space_operations |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 549 | * @mapping: " |
| 550 | * @pos: " |
| 551 | * @len: " |
| 552 | * @copied: " |
| 553 | * @page: " |
| 554 | * @fsdata: " |
| 555 | * |
| 556 | * simple_write_end does the minimum needed for updating a page after writing is |
| 557 | * done. It has the same API signature as the .write_end of |
| 558 | * address_space_operations vector. So it can just be set onto .write_end for |
| 559 | * FSes that don't need any other processing. i_mutex is assumed to be held. |
| 560 | * Block based filesystems should use generic_write_end(). |
| 561 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty |
| 562 | * is not called, so a filesystem that actually does store data in .write_inode |
| 563 | * should extend on what's done here with a call to mark_inode_dirty() in the |
| 564 | * case that i_size has changed. |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 565 | * |
| 566 | * Use *ONLY* with simple_readpage() |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 567 | */ |
| 568 | int simple_write_end(struct file *file, struct address_space *mapping, |
| 569 | loff_t pos, unsigned len, unsigned copied, |
| 570 | struct page *page, void *fsdata) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | { |
| 572 | struct inode *inode = page->mapping->host; |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 573 | loff_t last_pos = pos + copied; |
| 574 | |
| 575 | /* zero the stale part of the page if we did a short copy */ |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 576 | if (!PageUptodate(page)) { |
| 577 | if (copied < len) { |
| 578 | unsigned from = pos & (PAGE_SIZE - 1); |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 579 | |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 580 | zero_user(page, from + copied, len - copied); |
| 581 | } |
Nick Piggin | 955eff5 | 2007-02-20 13:58:08 -0800 | [diff] [blame] | 582 | SetPageUptodate(page); |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 583 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | /* |
| 585 | * No need to use i_size_read() here, the i_size |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 586 | * cannot change under us because we hold the i_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 587 | */ |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 588 | if (last_pos > inode->i_size) |
| 589 | i_size_write(inode, last_pos); |
| 590 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | set_page_dirty(page); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 592 | unlock_page(page); |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 593 | put_page(page); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 594 | |
| 595 | return copied; |
| 596 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 597 | EXPORT_SYMBOL(simple_write_end); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 598 | |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 599 | /* |
| 600 | * the inodes created here are not hashed. If you use iunique to generate |
| 601 | * unique inode values later for this filesystem, then you must take care |
| 602 | * to pass it an appropriate max_reserved value to avoid collisions. |
| 603 | */ |
Roberto Sassu | 7d683a0 | 2010-06-03 11:58:28 +0200 | [diff] [blame] | 604 | int simple_fill_super(struct super_block *s, unsigned long magic, |
Eric Biggers | cda3712 | 2017-03-25 21:15:37 -0700 | [diff] [blame] | 605 | const struct tree_descr *files) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | struct inode *inode; |
| 608 | struct dentry *root; |
| 609 | struct dentry *dentry; |
| 610 | int i; |
| 611 | |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 612 | s->s_blocksize = PAGE_SIZE; |
| 613 | s->s_blocksize_bits = PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | s->s_magic = magic; |
Hugh Dickins | 759b977 | 2007-03-05 00:30:28 -0800 | [diff] [blame] | 615 | s->s_op = &simple_super_operations; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | s->s_time_gran = 1; |
| 617 | |
| 618 | inode = new_inode(s); |
| 619 | if (!inode) |
| 620 | return -ENOMEM; |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 621 | /* |
| 622 | * because the root inode is 1, the files array must not contain an |
| 623 | * entry at index 1 |
| 624 | */ |
| 625 | inode->i_ino = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | inode->i_mode = S_IFDIR | 0755; |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 627 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | inode->i_op = &simple_dir_inode_operations; |
| 629 | inode->i_fop = &simple_dir_operations; |
Miklos Szeredi | bfe8684 | 2011-10-28 14:13:29 +0200 | [diff] [blame] | 630 | set_nlink(inode, 2); |
Al Viro | 48fde70 | 2012-01-08 22:15:13 -0500 | [diff] [blame] | 631 | root = d_make_root(inode); |
| 632 | if (!root) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 634 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
| 635 | if (!files->name) |
| 636 | continue; |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 637 | |
| 638 | /* warn if it tries to conflict with the root inode */ |
| 639 | if (unlikely(i == 1)) |
| 640 | printk(KERN_WARNING "%s: %s passed in a files array" |
| 641 | "with an index of 1!\n", __func__, |
| 642 | s->s_type->name); |
| 643 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | dentry = d_alloc_name(root, files->name); |
| 645 | if (!dentry) |
| 646 | goto out; |
| 647 | inode = new_inode(s); |
Konstantin Khlebnikov | 32096ea | 2011-11-01 16:12:33 +0300 | [diff] [blame] | 648 | if (!inode) { |
| 649 | dput(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 650 | goto out; |
Konstantin Khlebnikov | 32096ea | 2011-11-01 16:12:33 +0300 | [diff] [blame] | 651 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | inode->i_mode = S_IFREG | files->mode; |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 653 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 654 | inode->i_fop = files->ops; |
| 655 | inode->i_ino = i; |
| 656 | d_add(dentry, inode); |
| 657 | } |
| 658 | s->s_root = root; |
| 659 | return 0; |
| 660 | out: |
| 661 | d_genocide(root); |
Al Viro | 640946f2 | 2012-04-02 19:22:25 -0400 | [diff] [blame] | 662 | shrink_dcache_parent(root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 663 | dput(root); |
| 664 | return -ENOMEM; |
| 665 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 666 | EXPORT_SYMBOL(simple_fill_super); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 667 | |
| 668 | static DEFINE_SPINLOCK(pin_fs_lock); |
| 669 | |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 670 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | { |
| 672 | struct vfsmount *mnt = NULL; |
| 673 | spin_lock(&pin_fs_lock); |
| 674 | if (unlikely(!*mount)) { |
| 675 | spin_unlock(&pin_fs_lock); |
Linus Torvalds | 1751e8a | 2017-11-27 13:05:09 -0800 | [diff] [blame] | 676 | mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | if (IS_ERR(mnt)) |
| 678 | return PTR_ERR(mnt); |
| 679 | spin_lock(&pin_fs_lock); |
| 680 | if (!*mount) |
| 681 | *mount = mnt; |
| 682 | } |
| 683 | mntget(*mount); |
| 684 | ++*count; |
| 685 | spin_unlock(&pin_fs_lock); |
| 686 | mntput(mnt); |
| 687 | return 0; |
| 688 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 689 | EXPORT_SYMBOL(simple_pin_fs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | |
| 691 | void simple_release_fs(struct vfsmount **mount, int *count) |
| 692 | { |
| 693 | struct vfsmount *mnt; |
| 694 | spin_lock(&pin_fs_lock); |
| 695 | mnt = *mount; |
| 696 | if (!--*count) |
| 697 | *mount = NULL; |
| 698 | spin_unlock(&pin_fs_lock); |
| 699 | mntput(mnt); |
| 700 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 701 | EXPORT_SYMBOL(simple_release_fs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 702 | |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 703 | /** |
| 704 | * simple_read_from_buffer - copy data from the buffer to user space |
| 705 | * @to: the user space buffer to read to |
| 706 | * @count: the maximum number of bytes to read |
| 707 | * @ppos: the current position in the buffer |
| 708 | * @from: the buffer to read from |
| 709 | * @available: the size of the buffer |
| 710 | * |
| 711 | * The simple_read_from_buffer() function reads up to @count bytes from the |
| 712 | * buffer @from at offset @ppos into the user space address starting at @to. |
| 713 | * |
| 714 | * On success, the number of bytes read is returned and the offset @ppos is |
| 715 | * advanced by this number, or negative value is returned on error. |
| 716 | **/ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 717 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
| 718 | const void *from, size_t available) |
| 719 | { |
| 720 | loff_t pos = *ppos; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 721 | size_t ret; |
| 722 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 723 | if (pos < 0) |
| 724 | return -EINVAL; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 725 | if (pos >= available || !count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | return 0; |
| 727 | if (count > available - pos) |
| 728 | count = available - pos; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 729 | ret = copy_to_user(to, from + pos, count); |
| 730 | if (ret == count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | return -EFAULT; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 732 | count -= ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 | *ppos = pos + count; |
| 734 | return count; |
| 735 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 736 | EXPORT_SYMBOL(simple_read_from_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 737 | |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 738 | /** |
Jiri Slaby | 6a727b4 | 2010-05-01 23:51:22 +0200 | [diff] [blame] | 739 | * simple_write_to_buffer - copy data from user space to the buffer |
| 740 | * @to: the buffer to write to |
| 741 | * @available: the size of the buffer |
| 742 | * @ppos: the current position in the buffer |
| 743 | * @from: the user space buffer to read from |
| 744 | * @count: the maximum number of bytes to read |
| 745 | * |
| 746 | * The simple_write_to_buffer() function reads up to @count bytes from the user |
| 747 | * space address starting at @from into the buffer @to at offset @ppos. |
| 748 | * |
| 749 | * On success, the number of bytes written is returned and the offset @ppos is |
| 750 | * advanced by this number, or negative value is returned on error. |
| 751 | **/ |
| 752 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, |
| 753 | const void __user *from, size_t count) |
| 754 | { |
| 755 | loff_t pos = *ppos; |
| 756 | size_t res; |
| 757 | |
| 758 | if (pos < 0) |
| 759 | return -EINVAL; |
| 760 | if (pos >= available || !count) |
| 761 | return 0; |
| 762 | if (count > available - pos) |
| 763 | count = available - pos; |
| 764 | res = copy_from_user(to + pos, from, count); |
| 765 | if (res == count) |
| 766 | return -EFAULT; |
| 767 | count -= res; |
| 768 | *ppos = pos + count; |
| 769 | return count; |
| 770 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 771 | EXPORT_SYMBOL(simple_write_to_buffer); |
Jiri Slaby | 6a727b4 | 2010-05-01 23:51:22 +0200 | [diff] [blame] | 772 | |
| 773 | /** |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 774 | * memory_read_from_buffer - copy data from the buffer |
| 775 | * @to: the kernel space buffer to read to |
| 776 | * @count: the maximum number of bytes to read |
| 777 | * @ppos: the current position in the buffer |
| 778 | * @from: the buffer to read from |
| 779 | * @available: the size of the buffer |
| 780 | * |
| 781 | * The memory_read_from_buffer() function reads up to @count bytes from the |
| 782 | * buffer @from at offset @ppos into the kernel space address starting at @to. |
| 783 | * |
| 784 | * On success, the number of bytes read is returned and the offset @ppos is |
| 785 | * advanced by this number, or negative value is returned on error. |
| 786 | **/ |
Akinobu Mita | 93b0711 | 2008-06-05 22:46:21 -0700 | [diff] [blame] | 787 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
| 788 | const void *from, size_t available) |
| 789 | { |
| 790 | loff_t pos = *ppos; |
| 791 | |
| 792 | if (pos < 0) |
| 793 | return -EINVAL; |
| 794 | if (pos >= available) |
| 795 | return 0; |
| 796 | if (count > available - pos) |
| 797 | count = available - pos; |
| 798 | memcpy(to, from + pos, count); |
| 799 | *ppos = pos + count; |
| 800 | |
| 801 | return count; |
| 802 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 803 | EXPORT_SYMBOL(memory_read_from_buffer); |
Akinobu Mita | 93b0711 | 2008-06-05 22:46:21 -0700 | [diff] [blame] | 804 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 805 | /* |
| 806 | * Transaction based IO. |
| 807 | * The file expects a single write which triggers the transaction, and then |
| 808 | * possibly a read which collects the result - which is stored in a |
| 809 | * file-local buffer. |
| 810 | */ |
Ingo Molnar | 76791ab | 2009-03-25 16:48:35 +0100 | [diff] [blame] | 811 | |
| 812 | void simple_transaction_set(struct file *file, size_t n) |
| 813 | { |
| 814 | struct simple_transaction_argresp *ar = file->private_data; |
| 815 | |
| 816 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); |
| 817 | |
| 818 | /* |
| 819 | * The barrier ensures that ar->size will really remain zero until |
| 820 | * ar->data is ready for reading. |
| 821 | */ |
| 822 | smp_mb(); |
| 823 | ar->size = n; |
| 824 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 825 | EXPORT_SYMBOL(simple_transaction_set); |
Ingo Molnar | 76791ab | 2009-03-25 16:48:35 +0100 | [diff] [blame] | 826 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
| 828 | { |
| 829 | struct simple_transaction_argresp *ar; |
| 830 | static DEFINE_SPINLOCK(simple_transaction_lock); |
| 831 | |
| 832 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) |
| 833 | return ERR_PTR(-EFBIG); |
| 834 | |
| 835 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); |
| 836 | if (!ar) |
| 837 | return ERR_PTR(-ENOMEM); |
| 838 | |
| 839 | spin_lock(&simple_transaction_lock); |
| 840 | |
| 841 | /* only one write allowed per open */ |
| 842 | if (file->private_data) { |
| 843 | spin_unlock(&simple_transaction_lock); |
| 844 | free_page((unsigned long)ar); |
| 845 | return ERR_PTR(-EBUSY); |
| 846 | } |
| 847 | |
| 848 | file->private_data = ar; |
| 849 | |
| 850 | spin_unlock(&simple_transaction_lock); |
| 851 | |
| 852 | if (copy_from_user(ar->data, buf, size)) |
| 853 | return ERR_PTR(-EFAULT); |
| 854 | |
| 855 | return ar->data; |
| 856 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 857 | EXPORT_SYMBOL(simple_transaction_get); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | |
| 859 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) |
| 860 | { |
| 861 | struct simple_transaction_argresp *ar = file->private_data; |
| 862 | |
| 863 | if (!ar) |
| 864 | return 0; |
| 865 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); |
| 866 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 867 | EXPORT_SYMBOL(simple_transaction_read); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 868 | |
| 869 | int simple_transaction_release(struct inode *inode, struct file *file) |
| 870 | { |
| 871 | free_page((unsigned long)file->private_data); |
| 872 | return 0; |
| 873 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 874 | EXPORT_SYMBOL(simple_transaction_release); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 876 | /* Simple attribute files */ |
| 877 | |
| 878 | struct simple_attr { |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 879 | int (*get)(void *, u64 *); |
| 880 | int (*set)(void *, u64); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 881 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
| 882 | char set_buf[24]; |
| 883 | void *data; |
| 884 | const char *fmt; /* format for read operation */ |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 885 | struct mutex mutex; /* protects access to these buffers */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 886 | }; |
| 887 | |
| 888 | /* simple_attr_open is called by an actual attribute open file operation |
| 889 | * to set the attribute specific access operations. */ |
| 890 | int simple_attr_open(struct inode *inode, struct file *file, |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 891 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 892 | const char *fmt) |
| 893 | { |
| 894 | struct simple_attr *attr; |
| 895 | |
Eric Biggers | a65cab7 | 2020-03-07 18:38:49 -0800 | [diff] [blame] | 896 | attr = kzalloc(sizeof(*attr), GFP_KERNEL); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 897 | if (!attr) |
| 898 | return -ENOMEM; |
| 899 | |
| 900 | attr->get = get; |
| 901 | attr->set = set; |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 902 | attr->data = inode->i_private; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 903 | attr->fmt = fmt; |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 904 | mutex_init(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 905 | |
| 906 | file->private_data = attr; |
| 907 | |
| 908 | return nonseekable_open(inode, file); |
| 909 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 910 | EXPORT_SYMBOL_GPL(simple_attr_open); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 911 | |
Christoph Hellwig | 74bedc4 | 2008-02-08 04:20:28 -0800 | [diff] [blame] | 912 | int simple_attr_release(struct inode *inode, struct file *file) |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 913 | { |
| 914 | kfree(file->private_data); |
| 915 | return 0; |
| 916 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 917 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 918 | |
| 919 | /* read from the buffer that is filled with the get function */ |
| 920 | ssize_t simple_attr_read(struct file *file, char __user *buf, |
| 921 | size_t len, loff_t *ppos) |
| 922 | { |
| 923 | struct simple_attr *attr; |
| 924 | size_t size; |
| 925 | ssize_t ret; |
| 926 | |
| 927 | attr = file->private_data; |
| 928 | |
| 929 | if (!attr->get) |
| 930 | return -EACCES; |
| 931 | |
Christoph Hellwig | 9261303 | 2008-02-08 04:20:27 -0800 | [diff] [blame] | 932 | ret = mutex_lock_interruptible(&attr->mutex); |
| 933 | if (ret) |
| 934 | return ret; |
| 935 | |
Eric Biggers | a65cab7 | 2020-03-07 18:38:49 -0800 | [diff] [blame] | 936 | if (*ppos && attr->get_buf[0]) { |
| 937 | /* continued read */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 938 | size = strlen(attr->get_buf); |
Eric Biggers | a65cab7 | 2020-03-07 18:38:49 -0800 | [diff] [blame] | 939 | } else { |
| 940 | /* first read */ |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 941 | u64 val; |
| 942 | ret = attr->get(attr->data, &val); |
| 943 | if (ret) |
| 944 | goto out; |
| 945 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 946 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 947 | attr->fmt, (unsigned long long)val); |
| 948 | } |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 949 | |
| 950 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 951 | out: |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 952 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 953 | return ret; |
| 954 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 955 | EXPORT_SYMBOL_GPL(simple_attr_read); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 956 | |
| 957 | /* interpret the buffer as a number to call the set function with */ |
| 958 | ssize_t simple_attr_write(struct file *file, const char __user *buf, |
| 959 | size_t len, loff_t *ppos) |
| 960 | { |
| 961 | struct simple_attr *attr; |
Yicong Yang | 488dac0 | 2020-11-21 22:17:19 -0800 | [diff] [blame] | 962 | unsigned long long val; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 963 | size_t size; |
| 964 | ssize_t ret; |
| 965 | |
| 966 | attr = file->private_data; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 967 | if (!attr->set) |
| 968 | return -EACCES; |
| 969 | |
Christoph Hellwig | 9261303 | 2008-02-08 04:20:27 -0800 | [diff] [blame] | 970 | ret = mutex_lock_interruptible(&attr->mutex); |
| 971 | if (ret) |
| 972 | return ret; |
| 973 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 974 | ret = -EFAULT; |
| 975 | size = min(sizeof(attr->set_buf) - 1, len); |
| 976 | if (copy_from_user(attr->set_buf, buf, size)) |
| 977 | goto out; |
| 978 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 979 | attr->set_buf[size] = '\0'; |
Yicong Yang | 488dac0 | 2020-11-21 22:17:19 -0800 | [diff] [blame] | 980 | ret = kstrtoull(attr->set_buf, 0, &val); |
| 981 | if (ret) |
| 982 | goto out; |
Wu Fengguang | 05cc0ce | 2009-09-18 13:06:03 -0700 | [diff] [blame] | 983 | ret = attr->set(attr->data, val); |
| 984 | if (ret == 0) |
| 985 | ret = len; /* on success, claim we got the whole input */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 986 | out: |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 987 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 988 | return ret; |
| 989 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 990 | EXPORT_SYMBOL_GPL(simple_attr_write); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 991 | |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 992 | /** |
| 993 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation |
| 994 | * @sb: filesystem to do the file handle conversion on |
| 995 | * @fid: file handle to convert |
| 996 | * @fh_len: length of the file handle in bytes |
| 997 | * @fh_type: type of file handle |
| 998 | * @get_inode: filesystem callback to retrieve inode |
| 999 | * |
| 1000 | * This function decodes @fid as long as it has one of the well-known |
| 1001 | * Linux filehandle types and calls @get_inode on it to retrieve the |
| 1002 | * inode for the object specified in the file handle. |
| 1003 | */ |
| 1004 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, |
| 1005 | int fh_len, int fh_type, struct inode *(*get_inode) |
| 1006 | (struct super_block *sb, u64 ino, u32 gen)) |
| 1007 | { |
| 1008 | struct inode *inode = NULL; |
| 1009 | |
| 1010 | if (fh_len < 2) |
| 1011 | return NULL; |
| 1012 | |
| 1013 | switch (fh_type) { |
| 1014 | case FILEID_INO32_GEN: |
| 1015 | case FILEID_INO32_GEN_PARENT: |
| 1016 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); |
| 1017 | break; |
| 1018 | } |
| 1019 | |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1020 | return d_obtain_alias(inode); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 1021 | } |
| 1022 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); |
| 1023 | |
| 1024 | /** |
Yanchuan Nian | ca18683 | 2012-09-05 16:31:29 +0800 | [diff] [blame] | 1025 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 1026 | * @sb: filesystem to do the file handle conversion on |
| 1027 | * @fid: file handle to convert |
| 1028 | * @fh_len: length of the file handle in bytes |
| 1029 | * @fh_type: type of file handle |
| 1030 | * @get_inode: filesystem callback to retrieve inode |
| 1031 | * |
| 1032 | * This function decodes @fid as long as it has one of the well-known |
| 1033 | * Linux filehandle types and calls @get_inode on it to retrieve the |
| 1034 | * inode for the _parent_ object specified in the file handle if it |
| 1035 | * is specified in the file handle, or NULL otherwise. |
| 1036 | */ |
| 1037 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, |
| 1038 | int fh_len, int fh_type, struct inode *(*get_inode) |
| 1039 | (struct super_block *sb, u64 ino, u32 gen)) |
| 1040 | { |
| 1041 | struct inode *inode = NULL; |
| 1042 | |
| 1043 | if (fh_len <= 2) |
| 1044 | return NULL; |
| 1045 | |
| 1046 | switch (fh_type) { |
| 1047 | case FILEID_INO32_GEN_PARENT: |
| 1048 | inode = get_inode(sb, fid->i32.parent_ino, |
| 1049 | (fh_len > 3 ? fid->i32.parent_gen : 0)); |
| 1050 | break; |
| 1051 | } |
| 1052 | |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1053 | return d_obtain_alias(inode); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 1054 | } |
| 1055 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); |
| 1056 | |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1057 | /** |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1058 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
| 1059 | * |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1060 | * @file: file to synchronize |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1061 | * @start: start offset in bytes |
| 1062 | * @end: end offset in bytes (inclusive) |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1063 | * @datasync: only synchronize essential metadata if true |
| 1064 | * |
| 1065 | * This is a generic implementation of the fsync method for simple |
| 1066 | * filesystems which track all non-inode metadata in the buffers list |
| 1067 | * hanging off the address_space structure. |
| 1068 | */ |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1069 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
| 1070 | int datasync) |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1071 | { |
Christoph Hellwig | 7ea8085 | 2010-05-26 17:53:25 +0200 | [diff] [blame] | 1072 | struct inode *inode = file->f_mapping->host; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1073 | int err; |
| 1074 | int ret; |
| 1075 | |
Jeff Layton | 383aa54 | 2017-07-06 07:02:29 -0400 | [diff] [blame] | 1076 | err = file_write_and_wait_range(file, start, end); |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1077 | if (err) |
| 1078 | return err; |
| 1079 | |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 1080 | inode_lock(inode); |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1081 | ret = sync_mapping_buffers(inode->i_mapping); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1082 | if (!(inode->i_state & I_DIRTY_ALL)) |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1083 | goto out; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1084 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1085 | goto out; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1086 | |
Christoph Hellwig | c3765016 | 2010-10-06 10:48:20 +0200 | [diff] [blame] | 1087 | err = sync_inode_metadata(inode, 1); |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1088 | if (ret == 0) |
| 1089 | ret = err; |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1090 | |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1091 | out: |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 1092 | inode_unlock(inode); |
Jeff Layton | 383aa54 | 2017-07-06 07:02:29 -0400 | [diff] [blame] | 1093 | /* check and advance again to catch errors after syncing out buffers */ |
| 1094 | err = file_check_and_advance_wb_err(file); |
| 1095 | if (ret == 0) |
| 1096 | ret = err; |
| 1097 | return ret; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1098 | } |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1099 | EXPORT_SYMBOL(__generic_file_fsync); |
| 1100 | |
| 1101 | /** |
| 1102 | * generic_file_fsync - generic fsync implementation for simple filesystems |
| 1103 | * with flush |
| 1104 | * @file: file to synchronize |
| 1105 | * @start: start offset in bytes |
| 1106 | * @end: end offset in bytes (inclusive) |
| 1107 | * @datasync: only synchronize essential metadata if true |
| 1108 | * |
| 1109 | */ |
| 1110 | |
| 1111 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, |
| 1112 | int datasync) |
| 1113 | { |
| 1114 | struct inode *inode = file->f_mapping->host; |
| 1115 | int err; |
| 1116 | |
| 1117 | err = __generic_file_fsync(file, start, end, datasync); |
| 1118 | if (err) |
| 1119 | return err; |
Christoph Hellwig | 9398554 | 2020-05-13 14:36:00 +0200 | [diff] [blame] | 1120 | return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL); |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1121 | } |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1122 | EXPORT_SYMBOL(generic_file_fsync); |
| 1123 | |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1124 | /** |
| 1125 | * generic_check_addressable - Check addressability of file system |
| 1126 | * @blocksize_bits: log of file system block size |
| 1127 | * @num_blocks: number of blocks in file system |
| 1128 | * |
| 1129 | * Determine whether a file system with @num_blocks blocks (and a |
| 1130 | * block size of 2**@blocksize_bits) is addressable by the sector_t |
| 1131 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. |
| 1132 | */ |
| 1133 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) |
| 1134 | { |
| 1135 | u64 last_fs_block = num_blocks - 1; |
Joel Becker | a33f13e | 2010-08-16 12:10:17 -0700 | [diff] [blame] | 1136 | u64 last_fs_page = |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 1137 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1138 | |
| 1139 | if (unlikely(num_blocks == 0)) |
| 1140 | return 0; |
| 1141 | |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 1142 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1143 | return -EINVAL; |
| 1144 | |
Joel Becker | a33f13e | 2010-08-16 12:10:17 -0700 | [diff] [blame] | 1145 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
| 1146 | (last_fs_page > (pgoff_t)(~0ULL))) { |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1147 | return -EFBIG; |
| 1148 | } |
| 1149 | return 0; |
| 1150 | } |
| 1151 | EXPORT_SYMBOL(generic_check_addressable); |
| 1152 | |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1153 | /* |
| 1154 | * No-op implementation of ->fsync for in-memory filesystems. |
| 1155 | */ |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1156 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1157 | { |
| 1158 | return 0; |
| 1159 | } |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1160 | EXPORT_SYMBOL(noop_fsync); |
Al Viro | 87dc800 | 2013-09-16 10:30:04 -0400 | [diff] [blame] | 1161 | |
Dan Williams | f44c776 | 2018-03-07 15:26:44 -0800 | [diff] [blame] | 1162 | int noop_set_page_dirty(struct page *page) |
| 1163 | { |
| 1164 | /* |
| 1165 | * Unlike __set_page_dirty_no_writeback that handles dirty page |
| 1166 | * tracking in the page object, dax does all dirty tracking in |
| 1167 | * the inode address_space in response to mkwrite faults. In the |
| 1168 | * dax case we only need to worry about potentially dirty CPU |
| 1169 | * caches, not dirty page cache pages to write back. |
| 1170 | * |
| 1171 | * This callback is defined to prevent fallback to |
| 1172 | * __set_page_dirty_buffers() in set_page_dirty(). |
| 1173 | */ |
| 1174 | return 0; |
| 1175 | } |
| 1176 | EXPORT_SYMBOL_GPL(noop_set_page_dirty); |
| 1177 | |
| 1178 | void noop_invalidatepage(struct page *page, unsigned int offset, |
| 1179 | unsigned int length) |
| 1180 | { |
| 1181 | /* |
| 1182 | * There is no page cache to invalidate in the dax case, however |
| 1183 | * we need this callback defined to prevent falling back to |
| 1184 | * block_invalidatepage() in do_invalidatepage(). |
| 1185 | */ |
| 1186 | } |
| 1187 | EXPORT_SYMBOL_GPL(noop_invalidatepage); |
| 1188 | |
| 1189 | ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
| 1190 | { |
| 1191 | /* |
| 1192 | * iomap based filesystems support direct I/O without need for |
| 1193 | * this callback. However, it still needs to be set in |
| 1194 | * inode->a_ops so that open/fcntl know that direct I/O is |
| 1195 | * generally supported. |
| 1196 | */ |
| 1197 | return -EINVAL; |
| 1198 | } |
| 1199 | EXPORT_SYMBOL_GPL(noop_direct_IO); |
| 1200 | |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1201 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
| 1202 | void kfree_link(void *p) |
Al Viro | 87dc800 | 2013-09-16 10:30:04 -0400 | [diff] [blame] | 1203 | { |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1204 | kfree(p); |
Al Viro | 87dc800 | 2013-09-16 10:30:04 -0400 | [diff] [blame] | 1205 | } |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1206 | EXPORT_SYMBOL(kfree_link); |
Al Viro | 6987843 | 2013-10-02 22:35:11 -0400 | [diff] [blame] | 1207 | |
| 1208 | /* |
| 1209 | * nop .set_page_dirty method so that people can use .page_mkwrite on |
| 1210 | * anon inodes. |
| 1211 | */ |
| 1212 | static int anon_set_page_dirty(struct page *page) |
| 1213 | { |
| 1214 | return 0; |
| 1215 | }; |
| 1216 | |
| 1217 | /* |
| 1218 | * A single inode exists for all anon_inode files. Contrary to pipes, |
| 1219 | * anon_inode inodes have no associated per-instance data, so we need |
| 1220 | * only allocate one of them. |
| 1221 | */ |
| 1222 | struct inode *alloc_anon_inode(struct super_block *s) |
| 1223 | { |
| 1224 | static const struct address_space_operations anon_aops = { |
| 1225 | .set_page_dirty = anon_set_page_dirty, |
| 1226 | }; |
| 1227 | struct inode *inode = new_inode_pseudo(s); |
| 1228 | |
| 1229 | if (!inode) |
| 1230 | return ERR_PTR(-ENOMEM); |
| 1231 | |
| 1232 | inode->i_ino = get_next_ino(); |
| 1233 | inode->i_mapping->a_ops = &anon_aops; |
| 1234 | |
| 1235 | /* |
| 1236 | * Mark the inode dirty from the very beginning, |
| 1237 | * that way it will never be moved to the dirty |
| 1238 | * list because mark_inode_dirty() will think |
| 1239 | * that it already _is_ on the dirty list. |
| 1240 | */ |
| 1241 | inode->i_state = I_DIRTY; |
| 1242 | inode->i_mode = S_IRUSR | S_IWUSR; |
| 1243 | inode->i_uid = current_fsuid(); |
| 1244 | inode->i_gid = current_fsgid(); |
| 1245 | inode->i_flags |= S_PRIVATE; |
Deepa Dinamani | 078cd82 | 2016-09-14 07:48:04 -0700 | [diff] [blame] | 1246 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
Al Viro | 6987843 | 2013-10-02 22:35:11 -0400 | [diff] [blame] | 1247 | return inode; |
| 1248 | } |
| 1249 | EXPORT_SYMBOL(alloc_anon_inode); |
Jeff Layton | 1c994a0 | 2014-08-27 06:49:41 -0400 | [diff] [blame] | 1250 | |
| 1251 | /** |
| 1252 | * simple_nosetlease - generic helper for prohibiting leases |
| 1253 | * @filp: file pointer |
| 1254 | * @arg: type of lease to obtain |
| 1255 | * @flp: new lease supplied for insertion |
Jeff Layton | e6f5c78 | 2014-08-22 10:40:25 -0400 | [diff] [blame] | 1256 | * @priv: private data for lm_setup operation |
Jeff Layton | 1c994a0 | 2014-08-27 06:49:41 -0400 | [diff] [blame] | 1257 | * |
| 1258 | * Generic helper for filesystems that do not wish to allow leases to be set. |
| 1259 | * All arguments are ignored and it just returns -EINVAL. |
| 1260 | */ |
| 1261 | int |
Jeff Layton | e6f5c78 | 2014-08-22 10:40:25 -0400 | [diff] [blame] | 1262 | simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, |
| 1263 | void **priv) |
Jeff Layton | 1c994a0 | 2014-08-27 06:49:41 -0400 | [diff] [blame] | 1264 | { |
| 1265 | return -EINVAL; |
| 1266 | } |
| 1267 | EXPORT_SYMBOL(simple_nosetlease); |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1268 | |
Eric Biggers | 6ee9706 | 2019-04-11 16:16:30 -0700 | [diff] [blame] | 1269 | /** |
| 1270 | * simple_get_link - generic helper to get the target of "fast" symlinks |
| 1271 | * @dentry: not used here |
| 1272 | * @inode: the symlink inode |
| 1273 | * @done: not used here |
| 1274 | * |
| 1275 | * Generic helper for filesystems to use for symlink inodes where a pointer to |
| 1276 | * the symlink target is stored in ->i_link. NOTE: this isn't normally called, |
| 1277 | * since as an optimization the path lookup code uses any non-NULL ->i_link |
| 1278 | * directly, without calling ->get_link(). But ->get_link() still must be set, |
| 1279 | * to mark the inode_operations as being for a symlink. |
| 1280 | * |
| 1281 | * Return: the symlink target |
| 1282 | */ |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1283 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1284 | struct delayed_call *done) |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1285 | { |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1286 | return inode->i_link; |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1287 | } |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1288 | EXPORT_SYMBOL(simple_get_link); |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1289 | |
| 1290 | const struct inode_operations simple_symlink_inode_operations = { |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1291 | .get_link = simple_get_link, |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1292 | }; |
| 1293 | EXPORT_SYMBOL(simple_symlink_inode_operations); |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1294 | |
| 1295 | /* |
| 1296 | * Operations for a permanently empty directory. |
| 1297 | */ |
| 1298 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
| 1299 | { |
| 1300 | return ERR_PTR(-ENOENT); |
| 1301 | } |
| 1302 | |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 1303 | static int empty_dir_getattr(const struct path *path, struct kstat *stat, |
| 1304 | u32 request_mask, unsigned int query_flags) |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1305 | { |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 1306 | struct inode *inode = d_inode(path->dentry); |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1307 | generic_fillattr(inode, stat); |
| 1308 | return 0; |
| 1309 | } |
| 1310 | |
| 1311 | static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) |
| 1312 | { |
| 1313 | return -EPERM; |
| 1314 | } |
| 1315 | |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1316 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) |
| 1317 | { |
| 1318 | return -EOPNOTSUPP; |
| 1319 | } |
| 1320 | |
| 1321 | static const struct inode_operations empty_dir_inode_operations = { |
| 1322 | .lookup = empty_dir_lookup, |
| 1323 | .permission = generic_permission, |
| 1324 | .setattr = empty_dir_setattr, |
| 1325 | .getattr = empty_dir_getattr, |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1326 | .listxattr = empty_dir_listxattr, |
| 1327 | }; |
| 1328 | |
| 1329 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) |
| 1330 | { |
| 1331 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ |
| 1332 | return generic_file_llseek_size(file, offset, whence, 2, 2); |
| 1333 | } |
| 1334 | |
| 1335 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) |
| 1336 | { |
| 1337 | dir_emit_dots(file, ctx); |
| 1338 | return 0; |
| 1339 | } |
| 1340 | |
| 1341 | static const struct file_operations empty_dir_operations = { |
| 1342 | .llseek = empty_dir_llseek, |
| 1343 | .read = generic_read_dir, |
Al Viro | c51da20 | 2016-04-30 22:37:34 -0400 | [diff] [blame] | 1344 | .iterate_shared = empty_dir_readdir, |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1345 | .fsync = noop_fsync, |
| 1346 | }; |
| 1347 | |
| 1348 | |
| 1349 | void make_empty_dir_inode(struct inode *inode) |
| 1350 | { |
| 1351 | set_nlink(inode, 2); |
| 1352 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; |
| 1353 | inode->i_uid = GLOBAL_ROOT_UID; |
| 1354 | inode->i_gid = GLOBAL_ROOT_GID; |
| 1355 | inode->i_rdev = 0; |
Eric W. Biederman | 4b75de86 | 2015-08-12 15:00:12 -0500 | [diff] [blame] | 1356 | inode->i_size = 0; |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1357 | inode->i_blkbits = PAGE_SHIFT; |
| 1358 | inode->i_blocks = 0; |
| 1359 | |
| 1360 | inode->i_op = &empty_dir_inode_operations; |
Andreas Gruenbacher | f5c2443 | 2016-09-29 17:48:41 +0200 | [diff] [blame] | 1361 | inode->i_opflags &= ~IOP_XATTR; |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1362 | inode->i_fop = &empty_dir_operations; |
| 1363 | } |
| 1364 | |
| 1365 | bool is_empty_dir_inode(struct inode *inode) |
| 1366 | { |
| 1367 | return (inode->i_fop == &empty_dir_operations) && |
| 1368 | (inode->i_op == &empty_dir_inode_operations); |
| 1369 | } |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1370 | |
| 1371 | #ifdef CONFIG_UNICODE |
| 1372 | /* |
| 1373 | * Determine if the name of a dentry should be casefolded. |
| 1374 | * |
| 1375 | * Return: if names will need casefolding |
| 1376 | */ |
| 1377 | static bool needs_casefold(const struct inode *dir) |
| 1378 | { |
| 1379 | return IS_CASEFOLDED(dir) && dir->i_sb->s_encoding; |
| 1380 | } |
| 1381 | |
| 1382 | /** |
| 1383 | * generic_ci_d_compare - generic d_compare implementation for casefolding filesystems |
| 1384 | * @dentry: dentry whose name we are checking against |
| 1385 | * @len: len of name of dentry |
| 1386 | * @str: str pointer to name of dentry |
| 1387 | * @name: Name to compare against |
| 1388 | * |
| 1389 | * Return: 0 if names match, 1 if mismatch, or -ERRNO |
| 1390 | */ |
| 1391 | int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, |
| 1392 | const char *str, const struct qstr *name) |
| 1393 | { |
| 1394 | const struct dentry *parent = READ_ONCE(dentry->d_parent); |
| 1395 | const struct inode *dir = READ_ONCE(parent->d_inode); |
| 1396 | const struct super_block *sb = dentry->d_sb; |
| 1397 | const struct unicode_map *um = sb->s_encoding; |
| 1398 | struct qstr qstr = QSTR_INIT(str, len); |
| 1399 | char strbuf[DNAME_INLINE_LEN]; |
| 1400 | int ret; |
| 1401 | |
| 1402 | if (!dir || !needs_casefold(dir)) |
| 1403 | goto fallback; |
| 1404 | /* |
| 1405 | * If the dentry name is stored in-line, then it may be concurrently |
| 1406 | * modified by a rename. If this happens, the VFS will eventually retry |
| 1407 | * the lookup, so it doesn't matter what ->d_compare() returns. |
| 1408 | * However, it's unsafe to call utf8_strncasecmp() with an unstable |
| 1409 | * string. Therefore, we have to copy the name into a temporary buffer. |
| 1410 | */ |
| 1411 | if (len <= DNAME_INLINE_LEN - 1) { |
| 1412 | memcpy(strbuf, str, len); |
| 1413 | strbuf[len] = 0; |
| 1414 | qstr.name = strbuf; |
| 1415 | /* prevent compiler from optimizing out the temporary buffer */ |
| 1416 | barrier(); |
| 1417 | } |
| 1418 | ret = utf8_strncasecmp(um, name, &qstr); |
| 1419 | if (ret >= 0) |
| 1420 | return ret; |
| 1421 | |
| 1422 | if (sb_has_strict_encoding(sb)) |
| 1423 | return -EINVAL; |
| 1424 | fallback: |
| 1425 | if (len != name->len) |
| 1426 | return 1; |
| 1427 | return !!memcmp(str, name->name, len); |
| 1428 | } |
| 1429 | EXPORT_SYMBOL(generic_ci_d_compare); |
| 1430 | |
| 1431 | /** |
| 1432 | * generic_ci_d_hash - generic d_hash implementation for casefolding filesystems |
| 1433 | * @dentry: dentry of the parent directory |
| 1434 | * @str: qstr of name whose hash we should fill in |
| 1435 | * |
| 1436 | * Return: 0 if hash was successful or unchanged, and -EINVAL on error |
| 1437 | */ |
| 1438 | int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) |
| 1439 | { |
| 1440 | const struct inode *dir = READ_ONCE(dentry->d_inode); |
| 1441 | struct super_block *sb = dentry->d_sb; |
| 1442 | const struct unicode_map *um = sb->s_encoding; |
| 1443 | int ret = 0; |
| 1444 | |
| 1445 | if (!dir || !needs_casefold(dir)) |
| 1446 | return 0; |
| 1447 | |
| 1448 | ret = utf8_casefold_hash(um, dentry, str); |
| 1449 | if (ret < 0 && sb_has_strict_encoding(sb)) |
| 1450 | return -EINVAL; |
| 1451 | return 0; |
| 1452 | } |
| 1453 | EXPORT_SYMBOL(generic_ci_d_hash); |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1454 | |
| 1455 | static const struct dentry_operations generic_ci_dentry_ops = { |
| 1456 | .d_hash = generic_ci_d_hash, |
| 1457 | .d_compare = generic_ci_d_compare, |
| 1458 | }; |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1459 | #endif |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1460 | |
| 1461 | #ifdef CONFIG_FS_ENCRYPTION |
| 1462 | static const struct dentry_operations generic_encrypted_dentry_ops = { |
| 1463 | .d_revalidate = fscrypt_d_revalidate, |
| 1464 | }; |
| 1465 | #endif |
| 1466 | |
| 1467 | #if defined(CONFIG_FS_ENCRYPTION) && defined(CONFIG_UNICODE) |
| 1468 | static const struct dentry_operations generic_encrypted_ci_dentry_ops = { |
| 1469 | .d_hash = generic_ci_d_hash, |
| 1470 | .d_compare = generic_ci_d_compare, |
| 1471 | .d_revalidate = fscrypt_d_revalidate, |
| 1472 | }; |
| 1473 | #endif |
| 1474 | |
| 1475 | /** |
| 1476 | * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry |
| 1477 | * @dentry: dentry to set ops on |
| 1478 | * |
| 1479 | * Casefolded directories need d_hash and d_compare set, so that the dentries |
| 1480 | * contained in them are handled case-insensitively. Note that these operations |
| 1481 | * are needed on the parent directory rather than on the dentries in it, and |
| 1482 | * while the casefolding flag can be toggled on and off on an empty directory, |
| 1483 | * dentry_operations can't be changed later. As a result, if the filesystem has |
| 1484 | * casefolding support enabled at all, we have to give all dentries the |
| 1485 | * casefolding operations even if their inode doesn't have the casefolding flag |
| 1486 | * currently (and thus the casefolding ops would be no-ops for now). |
| 1487 | * |
| 1488 | * Encryption works differently in that the only dentry operation it needs is |
| 1489 | * d_revalidate, which it only needs on dentries that have the no-key name flag. |
| 1490 | * The no-key flag can't be set "later", so we don't have to worry about that. |
| 1491 | * |
| 1492 | * Finally, to maximize compatibility with overlayfs (which isn't compatible |
| 1493 | * with certain dentry operations) and to avoid taking an unnecessary |
| 1494 | * performance hit, we use custom dentry_operations for each possible |
| 1495 | * combination rather than always installing all operations. |
| 1496 | */ |
| 1497 | void generic_set_encrypted_ci_d_ops(struct dentry *dentry) |
| 1498 | { |
| 1499 | #ifdef CONFIG_FS_ENCRYPTION |
| 1500 | bool needs_encrypt_ops = dentry->d_flags & DCACHE_NOKEY_NAME; |
| 1501 | #endif |
| 1502 | #ifdef CONFIG_UNICODE |
| 1503 | bool needs_ci_ops = dentry->d_sb->s_encoding; |
| 1504 | #endif |
| 1505 | #if defined(CONFIG_FS_ENCRYPTION) && defined(CONFIG_UNICODE) |
| 1506 | if (needs_encrypt_ops && needs_ci_ops) { |
| 1507 | d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops); |
| 1508 | return; |
| 1509 | } |
| 1510 | #endif |
| 1511 | #ifdef CONFIG_FS_ENCRYPTION |
| 1512 | if (needs_encrypt_ops) { |
| 1513 | d_set_d_op(dentry, &generic_encrypted_dentry_ops); |
| 1514 | return; |
| 1515 | } |
| 1516 | #endif |
| 1517 | #ifdef CONFIG_UNICODE |
| 1518 | if (needs_ci_ops) { |
| 1519 | d_set_d_op(dentry, &generic_ci_dentry_ops); |
| 1520 | return; |
| 1521 | } |
| 1522 | #endif |
| 1523 | } |
| 1524 | EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops); |