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> |
Andrew Morton | 5ca1483 | 2022-09-09 13:57:41 -0700 | [diff] [blame] | 18 | #include <linux/iversion.h> |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 19 | #include <linux/writeback.h> |
Al Viro | ff01bb4 | 2011-09-16 02:31:11 -0400 | [diff] [blame] | 20 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 21 | #include <linux/fs_context.h> |
| 22 | #include <linux/pseudo_fs.h> |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 23 | #include <linux/fsnotify.h> |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 24 | #include <linux/unicode.h> |
| 25 | #include <linux/fscrypt.h> |
Christian Brauner | b28ddcc | 2024-02-19 16:30:57 +0100 | [diff] [blame] | 26 | #include <linux/pidfs.h> |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 27 | |
Linus Torvalds | 7c0f6ba | 2016-12-24 11:46:01 -0800 | [diff] [blame] | 28 | #include <linux/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Al Viro | a4464db | 2011-07-07 15:03:58 -0400 | [diff] [blame] | 30 | #include "internal.h" |
| 31 | |
Christian Brauner | b74d24f | 2023-01-13 12:49:12 +0100 | [diff] [blame] | 32 | int simple_getattr(struct mnt_idmap *idmap, const struct path *path, |
Christian Brauner | 549c729 | 2021-01-21 14:19:43 +0100 | [diff] [blame] | 33 | struct kstat *stat, u32 request_mask, |
| 34 | unsigned int query_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | { |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 36 | struct inode *inode = d_inode(path->dentry); |
Jeff Layton | 0d72b928 | 2023-08-07 15:38:33 -0400 | [diff] [blame] | 37 | generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 38 | stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | return 0; |
| 40 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 41 | EXPORT_SYMBOL(simple_getattr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 43 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | { |
Amir Goldstein | ae62bcb | 2023-10-23 17:30:49 +0300 | [diff] [blame] | 45 | u64 id = huge_encode_dev(dentry->d_sb->s_dev); |
| 46 | |
| 47 | buf->f_fsid = u64_to_fsid(id); |
David Howells | 726c334 | 2006-06-23 02:02:58 -0700 | [diff] [blame] | 48 | buf->f_type = dentry->d_sb->s_magic; |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 49 | buf->f_bsize = PAGE_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | buf->f_namelen = NAME_MAX; |
| 51 | return 0; |
| 52 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 53 | EXPORT_SYMBOL(simple_statfs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | |
| 55 | /* |
| 56 | * Retaining negative dentries for an in-memory filesystem just wastes |
| 57 | * memory and lookup time: arrange for them to be deleted immediately. |
| 58 | */ |
Al Viro | b26d4cd | 2013-10-25 18:47:37 -0400 | [diff] [blame] | 59 | int always_delete_dentry(const struct dentry *dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | { |
| 61 | return 1; |
| 62 | } |
Al Viro | b26d4cd | 2013-10-25 18:47:37 -0400 | [diff] [blame] | 63 | EXPORT_SYMBOL(always_delete_dentry); |
| 64 | |
| 65 | const struct dentry_operations simple_dentry_operations = { |
| 66 | .d_delete = always_delete_dentry, |
| 67 | }; |
| 68 | EXPORT_SYMBOL(simple_dentry_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | |
| 70 | /* |
| 71 | * Lookup the data. This is trivial - if the dentry didn't already |
| 72 | * exist, we know it is negative. Set d_op to delete negative dentries. |
| 73 | */ |
Al Viro | 00cd8dd | 2012-06-10 17:13:09 -0400 | [diff] [blame] | 74 | 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] | 75 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | if (dentry->d_name.len > NAME_MAX) |
| 77 | return ERR_PTR(-ENAMETOOLONG); |
Al Viro | 74931da | 2013-07-14 17:43:25 +0400 | [diff] [blame] | 78 | if (!dentry->d_sb->s_d_op) |
| 79 | d_set_d_op(dentry, &simple_dentry_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | d_add(dentry, NULL); |
| 81 | return NULL; |
| 82 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 83 | EXPORT_SYMBOL(simple_lookup); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | int dcache_dir_open(struct inode *inode, struct file *file) |
| 86 | { |
Al Viro | ba65dc5 | 2016-06-10 11:32:47 -0400 | [diff] [blame] | 87 | file->private_data = d_alloc_cursor(file->f_path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | |
| 89 | return file->private_data ? 0 : -ENOMEM; |
| 90 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 91 | EXPORT_SYMBOL(dcache_dir_open); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | |
| 93 | int dcache_dir_close(struct inode *inode, struct file *file) |
| 94 | { |
| 95 | dput(file->private_data); |
| 96 | return 0; |
| 97 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 98 | EXPORT_SYMBOL(dcache_dir_close); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 100 | /* parent is locked at least shared */ |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 101 | /* |
| 102 | * Returns an element of siblings' list. |
| 103 | * We are looking for <count>th positive after <p>; if |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 104 | * found, dentry is grabbed and returned to caller. |
| 105 | * If no such element exists, NULL is returned. |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 106 | */ |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 107 | static struct dentry *scan_positives(struct dentry *cursor, |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 108 | struct hlist_node **p, |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 109 | loff_t count, |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 110 | struct dentry *last) |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 111 | { |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 112 | struct dentry *dentry = cursor->d_parent, *found = NULL; |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 113 | |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 114 | spin_lock(&dentry->d_lock); |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 115 | while (*p) { |
| 116 | struct dentry *d = hlist_entry(*p, struct dentry, d_sib); |
| 117 | p = &d->d_sib.next; |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 118 | // we must at least skip cursors, to avoid livelocks |
| 119 | if (d->d_flags & DCACHE_DENTRY_CURSOR) |
| 120 | continue; |
| 121 | if (simple_positive(d) && !--count) { |
| 122 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); |
| 123 | if (simple_positive(d)) |
| 124 | found = dget_dlock(d); |
| 125 | spin_unlock(&d->d_lock); |
| 126 | if (likely(found)) |
| 127 | break; |
| 128 | count = 1; |
| 129 | } |
| 130 | if (need_resched()) { |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 131 | if (!hlist_unhashed(&cursor->d_sib)) |
| 132 | __hlist_del(&cursor->d_sib); |
| 133 | hlist_add_behind(&cursor->d_sib, &d->d_sib); |
| 134 | p = &cursor->d_sib.next; |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 135 | spin_unlock(&dentry->d_lock); |
| 136 | cond_resched(); |
| 137 | spin_lock(&dentry->d_lock); |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 138 | } |
| 139 | } |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 140 | spin_unlock(&dentry->d_lock); |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 141 | dput(last); |
| 142 | return found; |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 143 | } |
| 144 | |
Andrew Morton | 965c8e5 | 2012-12-17 15:59:39 -0800 | [diff] [blame] | 145 | 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] | 146 | { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 147 | struct dentry *dentry = file->f_path.dentry; |
Andrew Morton | 965c8e5 | 2012-12-17 15:59:39 -0800 | [diff] [blame] | 148 | switch (whence) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | case 1: |
| 150 | offset += file->f_pos; |
Gustavo A. R. Silva | df561f66 | 2020-08-23 17:36:59 -0500 | [diff] [blame] | 151 | fallthrough; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | case 0: |
| 153 | if (offset >= 0) |
| 154 | break; |
Gustavo A. R. Silva | df561f66 | 2020-08-23 17:36:59 -0500 | [diff] [blame] | 155 | fallthrough; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | default: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | return -EINVAL; |
| 158 | } |
| 159 | if (offset != file->f_pos) { |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 160 | struct dentry *cursor = file->private_data; |
| 161 | struct dentry *to = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 163 | inode_lock_shared(dentry->d_inode); |
| 164 | |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 165 | if (offset > 2) |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 166 | to = scan_positives(cursor, &dentry->d_children.first, |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 167 | offset - 2, NULL); |
| 168 | spin_lock(&dentry->d_lock); |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 169 | hlist_del_init(&cursor->d_sib); |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 170 | if (to) |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 171 | hlist_add_behind(&cursor->d_sib, &to->d_sib); |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 172 | spin_unlock(&dentry->d_lock); |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 173 | dput(to); |
| 174 | |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 175 | file->f_pos = offset; |
| 176 | |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 177 | inode_unlock_shared(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | return offset; |
| 180 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 181 | EXPORT_SYMBOL(dcache_dir_lseek); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | /* |
| 184 | * Directory is locked and all positive dentries in it are safe, since |
| 185 | * for ramfs-type trees they can't go away without unlink() or rmdir(), |
| 186 | * both impossible due to the lock on directory. |
| 187 | */ |
| 188 | |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 189 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | { |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 191 | struct dentry *dentry = file->f_path.dentry; |
| 192 | struct dentry *cursor = file->private_data; |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 193 | struct dentry *next = NULL; |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 194 | struct hlist_node **p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 196 | if (!dir_emit_dots(file, ctx)) |
| 197 | return 0; |
Al Viro | 4f42c1b | 2016-06-06 19:37:13 -0400 | [diff] [blame] | 198 | |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 199 | if (ctx->pos == 2) |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 200 | p = &dentry->d_children.first; |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 201 | else |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 202 | p = &cursor->d_sib.next; |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 203 | |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 204 | while ((next = scan_positives(cursor, p, 1, next)) != NULL) { |
Al Viro | 5f99f4e | 2013-05-15 20:23:06 -0400 | [diff] [blame] | 205 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
Jeff Layton | 364595a | 2023-03-30 06:41:43 -0400 | [diff] [blame] | 206 | d_inode(next)->i_ino, |
| 207 | fs_umode_to_dtype(d_inode(next)->i_mode))) |
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 | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 210 | p = &next->d_sib.next; |
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 | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 213 | hlist_del_init(&cursor->d_sib); |
Al Viro | 26b6c98 | 2019-09-20 16:32:42 -0400 | [diff] [blame] | 214 | if (next) |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 215 | hlist_add_before(&cursor->d_sib, &next->d_sib); |
Al Viro | d4f4de5 | 2019-09-15 12:12:39 -0400 | [diff] [blame] | 216 | spin_unlock(&dentry->d_lock); |
| 217 | dput(next); |
| 218 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | return 0; |
| 220 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 221 | EXPORT_SYMBOL(dcache_readdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | |
| 223 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) |
| 224 | { |
| 225 | return -EISDIR; |
| 226 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 227 | EXPORT_SYMBOL(generic_read_dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 229 | const struct file_operations simple_dir_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | .open = dcache_dir_open, |
| 231 | .release = dcache_dir_close, |
| 232 | .llseek = dcache_dir_lseek, |
| 233 | .read = generic_read_dir, |
Al Viro | 4e82901 | 2016-04-20 19:52:15 -0400 | [diff] [blame] | 234 | .iterate_shared = dcache_readdir, |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 235 | .fsync = noop_fsync, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | }; |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 237 | EXPORT_SYMBOL(simple_dir_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 239 | const struct inode_operations simple_dir_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 240 | .lookup = simple_lookup, |
| 241 | }; |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 242 | EXPORT_SYMBOL(simple_dir_inode_operations); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 243 | |
Chuck Lever | 7beea72 | 2024-02-17 15:23:47 -0500 | [diff] [blame] | 244 | /* 0 is '.', 1 is '..', so always start with offset 2 or more */ |
| 245 | enum { |
| 246 | DIR_OFFSET_MIN = 2, |
| 247 | }; |
| 248 | |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 249 | static void offset_set(struct dentry *dentry, long offset) |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 250 | { |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 251 | dentry->d_fsdata = (void *)offset; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 252 | } |
| 253 | |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 254 | static long dentry2offset(struct dentry *dentry) |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 255 | { |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 256 | return (long)dentry->d_fsdata; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 257 | } |
| 258 | |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 259 | static struct lock_class_key simple_offset_lock_class; |
Chuck Lever | bbaef79 | 2023-07-24 10:43:57 -0400 | [diff] [blame] | 260 | |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 261 | /** |
| 262 | * simple_offset_init - initialize an offset_ctx |
| 263 | * @octx: directory offset map to be initialized |
| 264 | * |
| 265 | */ |
| 266 | void simple_offset_init(struct offset_ctx *octx) |
| 267 | { |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 268 | mt_init_flags(&octx->mt, MT_FLAGS_ALLOC_RANGE); |
| 269 | lockdep_set_class(&octx->mt.ma_lock, &simple_offset_lock_class); |
Chuck Lever | 7beea72 | 2024-02-17 15:23:47 -0500 | [diff] [blame] | 270 | octx->next_offset = DIR_OFFSET_MIN; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 271 | } |
| 272 | |
| 273 | /** |
| 274 | * simple_offset_add - Add an entry to a directory's offset map |
| 275 | * @octx: directory offset ctx to be updated |
| 276 | * @dentry: new dentry being added |
| 277 | * |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 278 | * Returns zero on success. @octx and the dentry's offset are updated. |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 279 | * Otherwise, a negative errno value is returned. |
| 280 | */ |
| 281 | int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry) |
| 282 | { |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 283 | unsigned long offset; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 284 | int ret; |
| 285 | |
| 286 | if (dentry2offset(dentry) != 0) |
| 287 | return -EBUSY; |
| 288 | |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 289 | ret = mtree_alloc_cyclic(&octx->mt, &offset, dentry, DIR_OFFSET_MIN, |
| 290 | LONG_MAX, &octx->next_offset, GFP_KERNEL); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 291 | if (ret < 0) |
| 292 | return ret; |
| 293 | |
| 294 | offset_set(dentry, offset); |
| 295 | return 0; |
| 296 | } |
| 297 | |
Chuck Lever | 23cdd0e | 2024-04-15 11:20:54 -0400 | [diff] [blame] | 298 | static int simple_offset_replace(struct offset_ctx *octx, struct dentry *dentry, |
| 299 | long offset) |
| 300 | { |
| 301 | int ret; |
| 302 | |
| 303 | ret = mtree_store(&octx->mt, offset, dentry, GFP_KERNEL); |
| 304 | if (ret) |
| 305 | return ret; |
| 306 | offset_set(dentry, offset); |
| 307 | return 0; |
| 308 | } |
| 309 | |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 310 | /** |
| 311 | * simple_offset_remove - Remove an entry to a directory's offset map |
| 312 | * @octx: directory offset ctx to be updated |
| 313 | * @dentry: dentry being removed |
| 314 | * |
| 315 | */ |
| 316 | void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry) |
| 317 | { |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 318 | long offset; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 319 | |
| 320 | offset = dentry2offset(dentry); |
| 321 | if (offset == 0) |
| 322 | return; |
| 323 | |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 324 | mtree_erase(&octx->mt, offset); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 325 | offset_set(dentry, 0); |
| 326 | } |
| 327 | |
| 328 | /** |
Chuck Lever | ecba88a | 2024-02-17 15:23:54 -0500 | [diff] [blame] | 329 | * simple_offset_empty - Check if a dentry can be unlinked |
| 330 | * @dentry: dentry to be tested |
| 331 | * |
| 332 | * Returns 0 if @dentry is a non-empty directory; otherwise returns 1. |
| 333 | */ |
| 334 | int simple_offset_empty(struct dentry *dentry) |
| 335 | { |
| 336 | struct inode *inode = d_inode(dentry); |
| 337 | struct offset_ctx *octx; |
| 338 | struct dentry *child; |
| 339 | unsigned long index; |
| 340 | int ret = 1; |
| 341 | |
| 342 | if (!inode || !S_ISDIR(inode->i_mode)) |
| 343 | return ret; |
| 344 | |
| 345 | index = DIR_OFFSET_MIN; |
| 346 | octx = inode->i_op->get_offset_ctx(inode); |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 347 | mt_for_each(&octx->mt, child, index, LONG_MAX) { |
Chuck Lever | ecba88a | 2024-02-17 15:23:54 -0500 | [diff] [blame] | 348 | spin_lock(&child->d_lock); |
| 349 | if (simple_positive(child)) { |
| 350 | spin_unlock(&child->d_lock); |
| 351 | ret = 0; |
| 352 | break; |
| 353 | } |
| 354 | spin_unlock(&child->d_lock); |
| 355 | } |
| 356 | |
| 357 | return ret; |
| 358 | } |
| 359 | |
| 360 | /** |
Chuck Lever | 5a1a25b | 2024-04-15 11:20:55 -0400 | [diff] [blame] | 361 | * simple_offset_rename - handle directory offsets for rename |
| 362 | * @old_dir: parent directory of source entry |
| 363 | * @old_dentry: dentry of source entry |
| 364 | * @new_dir: parent_directory of destination entry |
| 365 | * @new_dentry: dentry of destination |
| 366 | * |
| 367 | * Caller provides appropriate serialization. |
| 368 | * |
Chuck Lever | ad191eb | 2024-04-15 11:20:56 -0400 | [diff] [blame] | 369 | * User space expects the directory offset value of the replaced |
| 370 | * (new) directory entry to be unchanged after a rename. |
| 371 | * |
Chuck Lever | 5a1a25b | 2024-04-15 11:20:55 -0400 | [diff] [blame] | 372 | * Returns zero on success, a negative errno value on failure. |
| 373 | */ |
| 374 | int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry, |
| 375 | struct inode *new_dir, struct dentry *new_dentry) |
| 376 | { |
| 377 | struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir); |
| 378 | struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir); |
Chuck Lever | ad191eb | 2024-04-15 11:20:56 -0400 | [diff] [blame] | 379 | long new_offset = dentry2offset(new_dentry); |
Chuck Lever | 5a1a25b | 2024-04-15 11:20:55 -0400 | [diff] [blame] | 380 | |
| 381 | simple_offset_remove(old_ctx, old_dentry); |
Chuck Lever | ad191eb | 2024-04-15 11:20:56 -0400 | [diff] [blame] | 382 | |
| 383 | if (new_offset) { |
| 384 | offset_set(new_dentry, 0); |
| 385 | return simple_offset_replace(new_ctx, old_dentry, new_offset); |
| 386 | } |
Chuck Lever | 5a1a25b | 2024-04-15 11:20:55 -0400 | [diff] [blame] | 387 | return simple_offset_add(new_ctx, old_dentry); |
| 388 | } |
| 389 | |
| 390 | /** |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 391 | * simple_offset_rename_exchange - exchange rename with directory offsets |
| 392 | * @old_dir: parent of dentry being moved |
| 393 | * @old_dentry: dentry being moved |
| 394 | * @new_dir: destination parent |
| 395 | * @new_dentry: destination dentry |
| 396 | * |
Chuck Lever | 23cdd0e | 2024-04-15 11:20:54 -0400 | [diff] [blame] | 397 | * This API preserves the directory offset values. Caller provides |
| 398 | * appropriate serialization. |
| 399 | * |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 400 | * Returns zero on success. Otherwise a negative errno is returned and the |
| 401 | * rename is rolled back. |
| 402 | */ |
| 403 | int simple_offset_rename_exchange(struct inode *old_dir, |
| 404 | struct dentry *old_dentry, |
| 405 | struct inode *new_dir, |
| 406 | struct dentry *new_dentry) |
| 407 | { |
| 408 | struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir); |
| 409 | struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir); |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 410 | long old_index = dentry2offset(old_dentry); |
| 411 | long new_index = dentry2offset(new_dentry); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 412 | int ret; |
| 413 | |
| 414 | simple_offset_remove(old_ctx, old_dentry); |
| 415 | simple_offset_remove(new_ctx, new_dentry); |
| 416 | |
Chuck Lever | 23cdd0e | 2024-04-15 11:20:54 -0400 | [diff] [blame] | 417 | ret = simple_offset_replace(new_ctx, old_dentry, new_index); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 418 | if (ret) |
| 419 | goto out_restore; |
| 420 | |
Chuck Lever | 23cdd0e | 2024-04-15 11:20:54 -0400 | [diff] [blame] | 421 | ret = simple_offset_replace(old_ctx, new_dentry, old_index); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 422 | if (ret) { |
| 423 | simple_offset_remove(new_ctx, old_dentry); |
| 424 | goto out_restore; |
| 425 | } |
| 426 | |
| 427 | ret = simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry); |
| 428 | if (ret) { |
| 429 | simple_offset_remove(new_ctx, old_dentry); |
| 430 | simple_offset_remove(old_ctx, new_dentry); |
| 431 | goto out_restore; |
| 432 | } |
| 433 | return 0; |
| 434 | |
| 435 | out_restore: |
Chuck Lever | 23cdd0e | 2024-04-15 11:20:54 -0400 | [diff] [blame] | 436 | (void)simple_offset_replace(old_ctx, old_dentry, old_index); |
| 437 | (void)simple_offset_replace(new_ctx, new_dentry, new_index); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 438 | return ret; |
| 439 | } |
| 440 | |
| 441 | /** |
| 442 | * simple_offset_destroy - Release offset map |
| 443 | * @octx: directory offset ctx that is about to be destroyed |
| 444 | * |
| 445 | * During fs teardown (eg. umount), a directory's offset map might still |
| 446 | * contain entries. xa_destroy() cleans out anything that remains. |
| 447 | */ |
| 448 | void simple_offset_destroy(struct offset_ctx *octx) |
| 449 | { |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 450 | mtree_destroy(&octx->mt); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 451 | } |
| 452 | |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 453 | static int offset_dir_open(struct inode *inode, struct file *file) |
| 454 | { |
| 455 | struct offset_ctx *ctx = inode->i_op->get_offset_ctx(inode); |
| 456 | |
| 457 | file->private_data = (void *)ctx->next_offset; |
| 458 | return 0; |
| 459 | } |
| 460 | |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 461 | /** |
| 462 | * offset_dir_llseek - Advance the read position of a directory descriptor |
| 463 | * @file: an open directory whose position is to be updated |
| 464 | * @offset: a byte offset |
| 465 | * @whence: enumerator describing the starting position for this update |
| 466 | * |
| 467 | * SEEK_END, SEEK_DATA, and SEEK_HOLE are not supported for directories. |
| 468 | * |
| 469 | * Returns the updated read position if successful; otherwise a |
| 470 | * negative errno is returned and the read position remains unchanged. |
| 471 | */ |
| 472 | static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence) |
| 473 | { |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 474 | struct inode *inode = file->f_inode; |
| 475 | struct offset_ctx *ctx = inode->i_op->get_offset_ctx(inode); |
| 476 | |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 477 | switch (whence) { |
| 478 | case SEEK_CUR: |
| 479 | offset += file->f_pos; |
| 480 | fallthrough; |
| 481 | case SEEK_SET: |
| 482 | if (offset >= 0) |
| 483 | break; |
| 484 | fallthrough; |
| 485 | default: |
| 486 | return -EINVAL; |
| 487 | } |
| 488 | |
Chuck Lever | 796432e | 2023-11-19 18:56:17 -0500 | [diff] [blame] | 489 | /* In this case, ->private_data is protected by f_pos_lock */ |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 490 | if (!offset) |
| 491 | file->private_data = (void *)ctx->next_offset; |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 492 | return vfs_setpos(file, offset, LONG_MAX); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 493 | } |
| 494 | |
Chuck Lever | 3f6d810 | 2024-02-17 15:23:40 -0500 | [diff] [blame] | 495 | static struct dentry *offset_find_next(struct offset_ctx *octx, loff_t offset) |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 496 | { |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 497 | MA_STATE(mas, &octx->mt, offset, offset); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 498 | struct dentry *child, *found = NULL; |
| 499 | |
| 500 | rcu_read_lock(); |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 501 | child = mas_find(&mas, LONG_MAX); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 502 | if (!child) |
| 503 | goto out; |
Chuck Lever | 2be4f05 | 2023-07-25 14:31:04 -0400 | [diff] [blame] | 504 | spin_lock(&child->d_lock); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 505 | if (simple_positive(child)) |
| 506 | found = dget_dlock(child); |
| 507 | spin_unlock(&child->d_lock); |
| 508 | out: |
| 509 | rcu_read_unlock(); |
| 510 | return found; |
| 511 | } |
| 512 | |
| 513 | static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry) |
| 514 | { |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 515 | struct inode *inode = d_inode(dentry); |
Chuck Lever | 0e4a862 | 2024-02-17 15:24:16 -0500 | [diff] [blame] | 516 | long offset = dentry2offset(dentry); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 517 | |
| 518 | return ctx->actor(ctx, dentry->d_name.name, dentry->d_name.len, offset, |
| 519 | inode->i_ino, fs_umode_to_dtype(inode->i_mode)); |
| 520 | } |
| 521 | |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 522 | static void offset_iterate_dir(struct inode *inode, struct dir_context *ctx, long last_index) |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 523 | { |
Chuck Lever | 3f6d810 | 2024-02-17 15:23:40 -0500 | [diff] [blame] | 524 | struct offset_ctx *octx = inode->i_op->get_offset_ctx(inode); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 525 | struct dentry *dentry; |
| 526 | |
| 527 | while (true) { |
Chuck Lever | 3f6d810 | 2024-02-17 15:23:40 -0500 | [diff] [blame] | 528 | dentry = offset_find_next(octx, ctx->pos); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 529 | if (!dentry) |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 530 | return; |
| 531 | |
| 532 | if (dentry2offset(dentry) >= last_index) { |
| 533 | dput(dentry); |
| 534 | return; |
| 535 | } |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 536 | |
| 537 | if (!offset_dir_emit(ctx, dentry)) { |
| 538 | dput(dentry); |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 539 | return; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 540 | } |
| 541 | |
Chuck Lever | 3f6d810 | 2024-02-17 15:23:40 -0500 | [diff] [blame] | 542 | ctx->pos = dentry2offset(dentry) + 1; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 543 | dput(dentry); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 544 | } |
| 545 | } |
| 546 | |
| 547 | /** |
| 548 | * offset_readdir - Emit entries starting at offset @ctx->pos |
| 549 | * @file: an open directory to iterate over |
| 550 | * @ctx: directory iteration context |
| 551 | * |
| 552 | * Caller must hold @file's i_rwsem to prevent insertion or removal of |
| 553 | * entries during this call. |
| 554 | * |
| 555 | * On entry, @ctx->pos contains an offset that represents the first entry |
| 556 | * to be read from the directory. |
| 557 | * |
| 558 | * The operation continues until there are no more entries to read, or |
| 559 | * until the ctx->actor indicates there is no more space in the caller's |
| 560 | * output buffer. |
| 561 | * |
| 562 | * On return, @ctx->pos contains an offset that will read the next entry |
Chuck Lever | 2be4f05 | 2023-07-25 14:31:04 -0400 | [diff] [blame] | 563 | * in this directory when offset_readdir() is called again with @ctx. |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 564 | * |
| 565 | * Return values: |
| 566 | * %0 - Complete |
| 567 | */ |
| 568 | static int offset_readdir(struct file *file, struct dir_context *ctx) |
| 569 | { |
| 570 | struct dentry *dir = file->f_path.dentry; |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 571 | long last_index = (long)file->private_data; |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 572 | |
| 573 | lockdep_assert_held(&d_inode(dir)->i_rwsem); |
| 574 | |
| 575 | if (!dir_emit_dots(file, ctx)) |
| 576 | return 0; |
| 577 | |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 578 | offset_iterate_dir(d_inode(dir), ctx, last_index); |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 579 | return 0; |
| 580 | } |
| 581 | |
| 582 | const struct file_operations simple_offset_dir_operations = { |
yangerkun | 64a7ce7 | 2024-07-31 12:38:35 +0800 | [diff] [blame] | 583 | .open = offset_dir_open, |
Chuck Lever | 6faddda69 | 2023-06-30 13:48:49 -0400 | [diff] [blame] | 584 | .llseek = offset_dir_llseek, |
| 585 | .iterate_shared = offset_readdir, |
| 586 | .read = generic_read_dir, |
| 587 | .fsync = noop_fsync, |
| 588 | }; |
| 589 | |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 590 | static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev) |
| 591 | { |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 592 | struct dentry *child = NULL, *d; |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 593 | |
| 594 | spin_lock(&parent->d_lock); |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 595 | d = prev ? d_next_sibling(prev) : d_first_child(parent); |
| 596 | hlist_for_each_entry_from(d, d_sib) { |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 597 | if (simple_positive(d)) { |
| 598 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); |
| 599 | if (simple_positive(d)) |
| 600 | child = dget_dlock(d); |
| 601 | spin_unlock(&d->d_lock); |
| 602 | if (likely(child)) |
| 603 | break; |
| 604 | } |
| 605 | } |
| 606 | spin_unlock(&parent->d_lock); |
| 607 | dput(prev); |
| 608 | return child; |
| 609 | } |
| 610 | |
| 611 | void simple_recursive_removal(struct dentry *dentry, |
| 612 | void (*callback)(struct dentry *)) |
| 613 | { |
| 614 | struct dentry *this = dget(dentry); |
| 615 | while (true) { |
| 616 | struct dentry *victim = NULL, *child; |
| 617 | struct inode *inode = this->d_inode; |
| 618 | |
| 619 | inode_lock(inode); |
| 620 | if (d_is_dir(this)) |
| 621 | inode->i_flags |= S_DEAD; |
| 622 | while ((child = find_next_child(this, victim)) == NULL) { |
| 623 | // kill and ascend |
| 624 | // update metadata while it's still locked |
Jeff Layton | f7f4385 | 2023-07-05 15:01:21 -0400 | [diff] [blame] | 625 | inode_set_ctime_current(inode); |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 626 | clear_nlink(inode); |
| 627 | inode_unlock(inode); |
| 628 | victim = this; |
| 629 | this = this->d_parent; |
| 630 | inode = this->d_inode; |
| 631 | inode_lock(inode); |
| 632 | if (simple_positive(victim)) { |
| 633 | d_invalidate(victim); // avoid lost mounts |
| 634 | if (d_is_dir(victim)) |
| 635 | fsnotify_rmdir(inode, victim); |
| 636 | else |
| 637 | fsnotify_unlink(inode, victim); |
| 638 | if (callback) |
| 639 | callback(victim); |
| 640 | dput(victim); // unpin it |
| 641 | } |
| 642 | if (victim == dentry) { |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 643 | inode_set_mtime_to_ts(inode, |
| 644 | inode_set_ctime_current(inode)); |
Al Viro | a3d1e7e | 2019-11-18 09:43:10 -0500 | [diff] [blame] | 645 | if (d_is_dir(dentry)) |
| 646 | drop_nlink(inode); |
| 647 | inode_unlock(inode); |
| 648 | dput(dentry); |
| 649 | return; |
| 650 | } |
| 651 | } |
| 652 | inode_unlock(inode); |
| 653 | this = child; |
| 654 | } |
| 655 | } |
| 656 | EXPORT_SYMBOL(simple_recursive_removal); |
| 657 | |
Hugh Dickins | 759b977 | 2007-03-05 00:30:28 -0800 | [diff] [blame] | 658 | static const struct super_operations simple_super_operations = { |
| 659 | .statfs = simple_statfs, |
| 660 | }; |
| 661 | |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 662 | 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] | 663 | { |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 664 | struct pseudo_fs_context *ctx = fc->fs_private; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | struct inode *root; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | |
Jeff Layton | 89a4eb4 | 2009-08-18 14:11:08 -0700 | [diff] [blame] | 667 | s->s_maxbytes = MAX_LFS_FILESIZE; |
Alex Nixon | 3971e1a | 2008-07-29 22:33:03 -0700 | [diff] [blame] | 668 | s->s_blocksize = PAGE_SIZE; |
| 669 | s->s_blocksize_bits = PAGE_SHIFT; |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 670 | s->s_magic = ctx->magic; |
| 671 | s->s_op = ctx->ops ?: &simple_super_operations; |
| 672 | s->s_xattr = ctx->xattr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 673 | s->s_time_gran = 1; |
| 674 | root = new_inode(s); |
| 675 | if (!root) |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 676 | return -ENOMEM; |
| 677 | |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 678 | /* |
| 679 | * since this is the first inode, make it number 1. New inodes created |
| 680 | * after this must take care not to collide with it (by passing |
| 681 | * max_reserved of 1 to iunique). |
| 682 | */ |
| 683 | root->i_ino = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 685 | simple_inode_init_ts(root); |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 686 | s->s_root = d_make_root(root); |
| 687 | if (!s->s_root) |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 688 | return -ENOMEM; |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 689 | s->s_d_op = ctx->dops; |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 690 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 691 | } |
Al Viro | 8d9e46d | 2019-05-11 11:43:59 -0400 | [diff] [blame] | 692 | |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 693 | static int pseudo_fs_get_tree(struct fs_context *fc) |
| 694 | { |
Al Viro | 2ac295d | 2019-06-01 20:48:55 -0400 | [diff] [blame] | 695 | return get_tree_nodev(fc, pseudo_fs_fill_super); |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 696 | } |
| 697 | |
| 698 | static void pseudo_fs_free(struct fs_context *fc) |
| 699 | { |
| 700 | kfree(fc->fs_private); |
| 701 | } |
| 702 | |
| 703 | static const struct fs_context_operations pseudo_fs_context_ops = { |
| 704 | .free = pseudo_fs_free, |
| 705 | .get_tree = pseudo_fs_get_tree, |
| 706 | }; |
| 707 | |
| 708 | /* |
| 709 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that |
| 710 | * will never be mountable) |
| 711 | */ |
| 712 | struct pseudo_fs_context *init_pseudo(struct fs_context *fc, |
| 713 | unsigned long magic) |
| 714 | { |
| 715 | struct pseudo_fs_context *ctx; |
| 716 | |
| 717 | ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL); |
| 718 | if (likely(ctx)) { |
| 719 | ctx->magic = magic; |
| 720 | fc->fs_private = ctx; |
| 721 | fc->ops = &pseudo_fs_context_ops; |
David Howells | db2c246 | 2019-03-25 16:38:26 +0000 | [diff] [blame] | 722 | fc->sb_flags |= SB_NOUSER; |
| 723 | fc->global = true; |
David Howells | 31d6d5c | 2019-03-25 16:38:23 +0000 | [diff] [blame] | 724 | } |
| 725 | return ctx; |
| 726 | } |
| 727 | EXPORT_SYMBOL(init_pseudo); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | |
Stephen Boyd | 20955e8 | 2012-04-05 14:25:09 -0700 | [diff] [blame] | 729 | int simple_open(struct inode *inode, struct file *file) |
| 730 | { |
| 731 | if (inode->i_private) |
| 732 | file->private_data = inode->i_private; |
| 733 | return 0; |
| 734 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 735 | EXPORT_SYMBOL(simple_open); |
Stephen Boyd | 20955e8 | 2012-04-05 14:25:09 -0700 | [diff] [blame] | 736 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 737 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
| 738 | { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 739 | struct inode *inode = d_inode(old_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 741 | inode_set_mtime_to_ts(dir, |
| 742 | inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 743 | inc_nlink(inode); |
Al Viro | 7de9c6ee | 2010-10-23 11:11:40 -0400 | [diff] [blame] | 744 | ihold(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 745 | dget(dentry); |
| 746 | d_instantiate(dentry, inode); |
| 747 | return 0; |
| 748 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 749 | EXPORT_SYMBOL(simple_link); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 751 | int simple_empty(struct dentry *dentry) |
| 752 | { |
| 753 | struct dentry *child; |
| 754 | int ret = 0; |
| 755 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 756 | spin_lock(&dentry->d_lock); |
Al Viro | da549bd | 2023-11-07 02:00:39 -0500 | [diff] [blame] | 757 | hlist_for_each_entry(child, &dentry->d_children, d_sib) { |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 758 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
| 759 | if (simple_positive(child)) { |
| 760 | spin_unlock(&child->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 761 | goto out; |
Nick Piggin | da50295 | 2011-01-07 17:49:33 +1100 | [diff] [blame] | 762 | } |
| 763 | spin_unlock(&child->d_lock); |
| 764 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 765 | ret = 1; |
| 766 | out: |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 767 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | return ret; |
| 769 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 770 | EXPORT_SYMBOL(simple_empty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 771 | |
| 772 | int simple_unlink(struct inode *dir, struct dentry *dentry) |
| 773 | { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 774 | struct inode *inode = d_inode(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 775 | |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 776 | inode_set_mtime_to_ts(dir, |
| 777 | inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 778 | drop_nlink(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 779 | dput(dentry); |
| 780 | return 0; |
| 781 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 782 | EXPORT_SYMBOL(simple_unlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 783 | |
| 784 | int simple_rmdir(struct inode *dir, struct dentry *dentry) |
| 785 | { |
| 786 | if (!simple_empty(dentry)) |
| 787 | return -ENOTEMPTY; |
| 788 | |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 789 | drop_nlink(d_inode(dentry)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 790 | simple_unlink(dir, dentry); |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 791 | drop_nlink(dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 792 | return 0; |
| 793 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 794 | EXPORT_SYMBOL(simple_rmdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 795 | |
Jeff Layton | 0c47679 | 2023-07-05 14:58:11 -0400 | [diff] [blame] | 796 | /** |
| 797 | * simple_rename_timestamp - update the various inode timestamps for rename |
| 798 | * @old_dir: old parent directory |
| 799 | * @old_dentry: dentry that is being renamed |
| 800 | * @new_dir: new parent directory |
| 801 | * @new_dentry: target for rename |
| 802 | * |
| 803 | * POSIX mandates that the old and new parent directories have their ctime and |
| 804 | * mtime updated, and that inodes of @old_dentry and @new_dentry (if any), have |
| 805 | * their ctime updated. |
| 806 | */ |
| 807 | void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry, |
| 808 | struct inode *new_dir, struct dentry *new_dentry) |
| 809 | { |
| 810 | struct inode *newino = d_inode(new_dentry); |
| 811 | |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 812 | inode_set_mtime_to_ts(old_dir, inode_set_ctime_current(old_dir)); |
Jeff Layton | 0c47679 | 2023-07-05 14:58:11 -0400 | [diff] [blame] | 813 | if (new_dir != old_dir) |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 814 | inode_set_mtime_to_ts(new_dir, |
| 815 | inode_set_ctime_current(new_dir)); |
Jeff Layton | 0c47679 | 2023-07-05 14:58:11 -0400 | [diff] [blame] | 816 | inode_set_ctime_current(d_inode(old_dentry)); |
| 817 | if (newino) |
| 818 | inode_set_ctime_current(newino); |
| 819 | } |
| 820 | EXPORT_SYMBOL_GPL(simple_rename_timestamp); |
| 821 | |
Lorenz Bauer | 6429e46 | 2021-10-28 10:47:21 +0100 | [diff] [blame] | 822 | int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry, |
| 823 | struct inode *new_dir, struct dentry *new_dentry) |
| 824 | { |
| 825 | bool old_is_dir = d_is_dir(old_dentry); |
| 826 | bool new_is_dir = d_is_dir(new_dentry); |
| 827 | |
| 828 | if (old_dir != new_dir && old_is_dir != new_is_dir) { |
| 829 | if (old_is_dir) { |
| 830 | drop_nlink(old_dir); |
| 831 | inc_nlink(new_dir); |
| 832 | } else { |
| 833 | drop_nlink(new_dir); |
| 834 | inc_nlink(old_dir); |
| 835 | } |
| 836 | } |
Jeff Layton | 0c47679 | 2023-07-05 14:58:11 -0400 | [diff] [blame] | 837 | simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); |
Lorenz Bauer | 6429e46 | 2021-10-28 10:47:21 +0100 | [diff] [blame] | 838 | return 0; |
| 839 | } |
| 840 | EXPORT_SYMBOL_GPL(simple_rename_exchange); |
| 841 | |
Christian Brauner | e18275a | 2023-01-13 12:49:17 +0100 | [diff] [blame] | 842 | int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir, |
Christian Brauner | 549c729 | 2021-01-21 14:19:43 +0100 | [diff] [blame] | 843 | struct dentry *old_dentry, struct inode *new_dir, |
| 844 | struct dentry *new_dentry, unsigned int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 845 | { |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 846 | int they_are_dirs = d_is_dir(old_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 847 | |
Lorenz Bauer | 3871cb8 | 2021-10-28 10:47:22 +0100 | [diff] [blame] | 848 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) |
Miklos Szeredi | e0e0be8 | 2016-09-27 11:03:57 +0200 | [diff] [blame] | 849 | return -EINVAL; |
| 850 | |
Lorenz Bauer | 3871cb8 | 2021-10-28 10:47:22 +0100 | [diff] [blame] | 851 | if (flags & RENAME_EXCHANGE) |
| 852 | return simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry); |
| 853 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 854 | if (!simple_empty(new_dentry)) |
| 855 | return -ENOTEMPTY; |
| 856 | |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 857 | if (d_really_is_positive(new_dentry)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | simple_unlink(new_dir, new_dentry); |
Al Viro | 841590c | 2011-07-21 15:49:09 -0400 | [diff] [blame] | 859 | if (they_are_dirs) { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 860 | drop_nlink(d_inode(new_dentry)); |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 861 | drop_nlink(old_dir); |
Al Viro | 841590c | 2011-07-21 15:49:09 -0400 | [diff] [blame] | 862 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | } else if (they_are_dirs) { |
Dave Hansen | 9a53c3a | 2006-09-30 23:29:03 -0700 | [diff] [blame] | 864 | drop_nlink(old_dir); |
Dave Hansen | d8c76e6 | 2006-09-30 23:29:04 -0700 | [diff] [blame] | 865 | inc_nlink(new_dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 866 | } |
| 867 | |
Jeff Layton | 0c47679 | 2023-07-05 14:58:11 -0400 | [diff] [blame] | 868 | simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 869 | return 0; |
| 870 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 871 | EXPORT_SYMBOL(simple_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 872 | |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 873 | /** |
Christoph Hellwig | eef2380 | 2010-06-04 11:30:01 +0200 | [diff] [blame] | 874 | * simple_setattr - setattr for simple filesystem |
Christian Brauner | c1632a0 | 2023-01-13 12:49:11 +0100 | [diff] [blame] | 875 | * @idmap: idmap of the target mount |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 876 | * @dentry: dentry |
| 877 | * @iattr: iattr structure |
| 878 | * |
| 879 | * Returns 0 on success, -error on failure. |
| 880 | * |
Christoph Hellwig | eef2380 | 2010-06-04 11:30:01 +0200 | [diff] [blame] | 881 | * simple_setattr is a simple ->setattr implementation without a proper |
| 882 | * implementation of size changes. |
| 883 | * |
| 884 | * It can either be used for in-memory filesystems or special files |
| 885 | * on simple regular filesystems. Anything that needs to change on-disk |
| 886 | * or wire state on size changes needs its own setattr method. |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 887 | */ |
Christian Brauner | c1632a0 | 2023-01-13 12:49:11 +0100 | [diff] [blame] | 888 | int simple_setattr(struct mnt_idmap *idmap, struct dentry *dentry, |
Christian Brauner | 549c729 | 2021-01-21 14:19:43 +0100 | [diff] [blame] | 889 | struct iattr *iattr) |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 890 | { |
David Howells | dea655c | 2015-03-17 22:26:15 +0000 | [diff] [blame] | 891 | struct inode *inode = d_inode(dentry); |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 892 | int error; |
| 893 | |
Christian Brauner | c1632a0 | 2023-01-13 12:49:11 +0100 | [diff] [blame] | 894 | error = setattr_prepare(idmap, dentry, iattr); |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 895 | if (error) |
| 896 | return error; |
| 897 | |
Christoph Hellwig | 2c27c65 | 2010-06-04 11:30:04 +0200 | [diff] [blame] | 898 | if (iattr->ia_valid & ATTR_SIZE) |
| 899 | truncate_setsize(inode, iattr->ia_size); |
Christian Brauner | c1632a0 | 2023-01-13 12:49:11 +0100 | [diff] [blame] | 900 | setattr_copy(idmap, inode, iattr); |
Christoph Hellwig | eef2380 | 2010-06-04 11:30:01 +0200 | [diff] [blame] | 901 | mark_inode_dirty(inode); |
| 902 | return 0; |
npiggin@suse.de | 7bb46a6 | 2010-05-27 01:05:33 +1000 | [diff] [blame] | 903 | } |
| 904 | EXPORT_SYMBOL(simple_setattr); |
| 905 | |
Matthew Wilcox (Oracle) | a77f580 | 2022-04-29 11:49:41 -0400 | [diff] [blame] | 906 | static int simple_read_folio(struct file *file, struct folio *folio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | { |
Matthew Wilcox (Oracle) | a77f580 | 2022-04-29 11:49:41 -0400 | [diff] [blame] | 908 | folio_zero_range(folio, 0, folio_size(folio)); |
| 909 | flush_dcache_folio(folio); |
| 910 | folio_mark_uptodate(folio); |
| 911 | folio_unlock(folio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | return 0; |
| 913 | } |
| 914 | |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 915 | int simple_write_begin(struct file *file, struct address_space *mapping, |
Matthew Wilcox (Oracle) | 9d6b0cd | 2022-02-22 14:31:43 -0500 | [diff] [blame] | 916 | loff_t pos, unsigned len, |
Matthew Wilcox (Oracle) | 1da8661 | 2024-07-15 14:24:01 -0400 | [diff] [blame] | 917 | struct folio **foliop, void **fsdata) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 918 | { |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 919 | struct folio *folio; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 920 | |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 921 | folio = __filemap_get_folio(mapping, pos / PAGE_SIZE, FGP_WRITEBEGIN, |
| 922 | mapping_gfp_mask(mapping)); |
| 923 | if (IS_ERR(folio)) |
| 924 | return PTR_ERR(folio); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 925 | |
Matthew Wilcox (Oracle) | 1da8661 | 2024-07-15 14:24:01 -0400 | [diff] [blame] | 926 | *foliop = folio; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 927 | |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 928 | if (!folio_test_uptodate(folio) && (len != folio_size(folio))) { |
| 929 | size_t from = offset_in_folio(folio, pos); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 930 | |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 931 | folio_zero_segments(folio, 0, from, |
| 932 | from + len, folio_size(folio)); |
Boaz Harrosh | 193cf4b | 2010-01-12 16:18:08 +0200 | [diff] [blame] | 933 | } |
| 934 | return 0; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 935 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 936 | EXPORT_SYMBOL(simple_write_begin); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 937 | |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 938 | /** |
| 939 | * simple_write_end - .write_end helper for non-block-device FSes |
Randy Dunlap | 8e88bfb | 2019-10-14 14:12:14 -0700 | [diff] [blame] | 940 | * @file: See .write_end of address_space_operations |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 941 | * @mapping: " |
| 942 | * @pos: " |
| 943 | * @len: " |
| 944 | * @copied: " |
Matthew Wilcox (Oracle) | a225800 | 2024-07-10 15:45:32 -0400 | [diff] [blame] | 945 | * @folio: " |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 946 | * @fsdata: " |
| 947 | * |
Matthew Wilcox (Oracle) | a225800 | 2024-07-10 15:45:32 -0400 | [diff] [blame] | 948 | * simple_write_end does the minimum needed for updating a folio after |
| 949 | * writing is done. It has the same API signature as the .write_end of |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 950 | * address_space_operations vector. So it can just be set onto .write_end for |
| 951 | * FSes that don't need any other processing. i_mutex is assumed to be held. |
| 952 | * Block based filesystems should use generic_write_end(). |
| 953 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty |
| 954 | * is not called, so a filesystem that actually does store data in .write_inode |
| 955 | * should extend on what's done here with a call to mark_inode_dirty() in the |
| 956 | * case that i_size has changed. |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 957 | * |
Matthew Wilcox (Oracle) | a77f580 | 2022-04-29 11:49:41 -0400 | [diff] [blame] | 958 | * Use *ONLY* with simple_read_folio() |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 959 | */ |
Christoph Hellwig | c1e3dbe | 2021-06-28 19:36:09 -0700 | [diff] [blame] | 960 | static int simple_write_end(struct file *file, struct address_space *mapping, |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 961 | loff_t pos, unsigned len, unsigned copied, |
Matthew Wilcox (Oracle) | a225800 | 2024-07-10 15:45:32 -0400 | [diff] [blame] | 962 | struct folio *folio, void *fsdata) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 963 | { |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 964 | struct inode *inode = folio->mapping->host; |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 965 | loff_t last_pos = pos + copied; |
| 966 | |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 967 | /* zero the stale part of the folio if we did a short copy */ |
| 968 | if (!folio_test_uptodate(folio)) { |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 969 | if (copied < len) { |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 970 | size_t from = offset_in_folio(folio, pos); |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 971 | |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 972 | folio_zero_range(folio, from + copied, len - copied); |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 973 | } |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 974 | folio_mark_uptodate(folio); |
Al Viro | 04fff64 | 2016-08-29 22:39:56 -0400 | [diff] [blame] | 975 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | /* |
| 977 | * No need to use i_size_read() here, the i_size |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 978 | * cannot change under us because we hold the i_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 979 | */ |
Boaz Harrosh | ad2a722f | 2010-01-12 15:13:47 +0200 | [diff] [blame] | 980 | if (last_pos > inode->i_size) |
| 981 | i_size_write(inode, last_pos); |
| 982 | |
Matthew Wilcox (Oracle) | 5522d9f | 2023-08-21 15:13:22 +0100 | [diff] [blame] | 983 | folio_mark_dirty(folio); |
| 984 | folio_unlock(folio); |
| 985 | folio_put(folio); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 986 | |
| 987 | return copied; |
| 988 | } |
Christoph Hellwig | c1e3dbe | 2021-06-28 19:36:09 -0700 | [diff] [blame] | 989 | |
| 990 | /* |
| 991 | * Provides ramfs-style behavior: data in the pagecache, but no writeback. |
| 992 | */ |
| 993 | const struct address_space_operations ram_aops = { |
Matthew Wilcox (Oracle) | a77f580 | 2022-04-29 11:49:41 -0400 | [diff] [blame] | 994 | .read_folio = simple_read_folio, |
Christoph Hellwig | c1e3dbe | 2021-06-28 19:36:09 -0700 | [diff] [blame] | 995 | .write_begin = simple_write_begin, |
| 996 | .write_end = simple_write_end, |
Matthew Wilcox (Oracle) | 46de8b97 | 2022-02-09 20:22:13 +0000 | [diff] [blame] | 997 | .dirty_folio = noop_dirty_folio, |
Christoph Hellwig | c1e3dbe | 2021-06-28 19:36:09 -0700 | [diff] [blame] | 998 | }; |
| 999 | EXPORT_SYMBOL(ram_aops); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 1000 | |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 1001 | /* |
| 1002 | * the inodes created here are not hashed. If you use iunique to generate |
| 1003 | * unique inode values later for this filesystem, then you must take care |
| 1004 | * to pass it an appropriate max_reserved value to avoid collisions. |
| 1005 | */ |
Roberto Sassu | 7d683a0 | 2010-06-03 11:58:28 +0200 | [diff] [blame] | 1006 | int simple_fill_super(struct super_block *s, unsigned long magic, |
Eric Biggers | cda3712 | 2017-03-25 21:15:37 -0700 | [diff] [blame] | 1007 | const struct tree_descr *files) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1008 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1009 | struct inode *inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1010 | struct dentry *dentry; |
| 1011 | int i; |
| 1012 | |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 1013 | s->s_blocksize = PAGE_SIZE; |
| 1014 | s->s_blocksize_bits = PAGE_SHIFT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1015 | s->s_magic = magic; |
Hugh Dickins | 759b977 | 2007-03-05 00:30:28 -0800 | [diff] [blame] | 1016 | s->s_op = &simple_super_operations; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1017 | s->s_time_gran = 1; |
| 1018 | |
| 1019 | inode = new_inode(s); |
| 1020 | if (!inode) |
| 1021 | return -ENOMEM; |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 1022 | /* |
| 1023 | * because the root inode is 1, the files array must not contain an |
| 1024 | * entry at index 1 |
| 1025 | */ |
| 1026 | inode->i_ino = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1027 | inode->i_mode = S_IFDIR | 0755; |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 1028 | simple_inode_init_ts(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1029 | inode->i_op = &simple_dir_inode_operations; |
| 1030 | inode->i_fop = &simple_dir_operations; |
Miklos Szeredi | bfe8684 | 2011-10-28 14:13:29 +0200 | [diff] [blame] | 1031 | set_nlink(inode, 2); |
Al Viro | 715cd66 | 2023-11-11 15:56:55 -0500 | [diff] [blame] | 1032 | s->s_root = d_make_root(inode); |
| 1033 | if (!s->s_root) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1034 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1035 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
| 1036 | if (!files->name) |
| 1037 | continue; |
Jeff Layton | 1a1c9bb | 2007-05-08 00:32:31 -0700 | [diff] [blame] | 1038 | |
| 1039 | /* warn if it tries to conflict with the root inode */ |
| 1040 | if (unlikely(i == 1)) |
| 1041 | printk(KERN_WARNING "%s: %s passed in a files array" |
| 1042 | "with an index of 1!\n", __func__, |
| 1043 | s->s_type->name); |
| 1044 | |
Al Viro | 715cd66 | 2023-11-11 15:56:55 -0500 | [diff] [blame] | 1045 | dentry = d_alloc_name(s->s_root, files->name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1046 | if (!dentry) |
Al Viro | 715cd66 | 2023-11-11 15:56:55 -0500 | [diff] [blame] | 1047 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1048 | inode = new_inode(s); |
Konstantin Khlebnikov | 32096ea | 2011-11-01 16:12:33 +0300 | [diff] [blame] | 1049 | if (!inode) { |
| 1050 | dput(dentry); |
Al Viro | 715cd66 | 2023-11-11 15:56:55 -0500 | [diff] [blame] | 1051 | return -ENOMEM; |
Konstantin Khlebnikov | 32096ea | 2011-11-01 16:12:33 +0300 | [diff] [blame] | 1052 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1053 | inode->i_mode = S_IFREG | files->mode; |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 1054 | simple_inode_init_ts(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1055 | inode->i_fop = files->ops; |
| 1056 | inode->i_ino = i; |
| 1057 | d_add(dentry, inode); |
| 1058 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1060 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1061 | EXPORT_SYMBOL(simple_fill_super); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1062 | |
| 1063 | static DEFINE_SPINLOCK(pin_fs_lock); |
| 1064 | |
Trond Myklebust | 1f5ce9e | 2006-06-09 09:34:16 -0400 | [diff] [blame] | 1065 | 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] | 1066 | { |
| 1067 | struct vfsmount *mnt = NULL; |
| 1068 | spin_lock(&pin_fs_lock); |
| 1069 | if (unlikely(!*mount)) { |
| 1070 | spin_unlock(&pin_fs_lock); |
Linus Torvalds | 1751e8a | 2017-11-27 13:05:09 -0800 | [diff] [blame] | 1071 | mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | if (IS_ERR(mnt)) |
| 1073 | return PTR_ERR(mnt); |
| 1074 | spin_lock(&pin_fs_lock); |
| 1075 | if (!*mount) |
| 1076 | *mount = mnt; |
| 1077 | } |
| 1078 | mntget(*mount); |
| 1079 | ++*count; |
| 1080 | spin_unlock(&pin_fs_lock); |
| 1081 | mntput(mnt); |
| 1082 | return 0; |
| 1083 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1084 | EXPORT_SYMBOL(simple_pin_fs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1085 | |
| 1086 | void simple_release_fs(struct vfsmount **mount, int *count) |
| 1087 | { |
| 1088 | struct vfsmount *mnt; |
| 1089 | spin_lock(&pin_fs_lock); |
| 1090 | mnt = *mount; |
| 1091 | if (!--*count) |
| 1092 | *mount = NULL; |
| 1093 | spin_unlock(&pin_fs_lock); |
| 1094 | mntput(mnt); |
| 1095 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1096 | EXPORT_SYMBOL(simple_release_fs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1097 | |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 1098 | /** |
| 1099 | * simple_read_from_buffer - copy data from the buffer to user space |
| 1100 | * @to: the user space buffer to read to |
| 1101 | * @count: the maximum number of bytes to read |
| 1102 | * @ppos: the current position in the buffer |
| 1103 | * @from: the buffer to read from |
| 1104 | * @available: the size of the buffer |
| 1105 | * |
| 1106 | * The simple_read_from_buffer() function reads up to @count bytes from the |
| 1107 | * buffer @from at offset @ppos into the user space address starting at @to. |
| 1108 | * |
| 1109 | * On success, the number of bytes read is returned and the offset @ppos is |
| 1110 | * advanced by this number, or negative value is returned on error. |
| 1111 | **/ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1112 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
| 1113 | const void *from, size_t available) |
| 1114 | { |
| 1115 | loff_t pos = *ppos; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 1116 | size_t ret; |
| 1117 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1118 | if (pos < 0) |
| 1119 | return -EINVAL; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 1120 | if (pos >= available || !count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | return 0; |
| 1122 | if (count > available - pos) |
| 1123 | count = available - pos; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 1124 | ret = copy_to_user(to, from + pos, count); |
| 1125 | if (ret == count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | return -EFAULT; |
Steven Rostedt | 14be274 | 2009-09-18 13:05:42 -0700 | [diff] [blame] | 1127 | count -= ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1128 | *ppos = pos + count; |
| 1129 | return count; |
| 1130 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1131 | EXPORT_SYMBOL(simple_read_from_buffer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1132 | |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 1133 | /** |
Jiri Slaby | 6a727b4 | 2010-05-01 23:51:22 +0200 | [diff] [blame] | 1134 | * simple_write_to_buffer - copy data from user space to the buffer |
| 1135 | * @to: the buffer to write to |
| 1136 | * @available: the size of the buffer |
| 1137 | * @ppos: the current position in the buffer |
| 1138 | * @from: the user space buffer to read from |
| 1139 | * @count: the maximum number of bytes to read |
| 1140 | * |
| 1141 | * The simple_write_to_buffer() function reads up to @count bytes from the user |
| 1142 | * space address starting at @from into the buffer @to at offset @ppos. |
| 1143 | * |
| 1144 | * On success, the number of bytes written is returned and the offset @ppos is |
| 1145 | * advanced by this number, or negative value is returned on error. |
| 1146 | **/ |
| 1147 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, |
| 1148 | const void __user *from, size_t count) |
| 1149 | { |
| 1150 | loff_t pos = *ppos; |
| 1151 | size_t res; |
| 1152 | |
| 1153 | if (pos < 0) |
| 1154 | return -EINVAL; |
| 1155 | if (pos >= available || !count) |
| 1156 | return 0; |
| 1157 | if (count > available - pos) |
| 1158 | count = available - pos; |
| 1159 | res = copy_from_user(to + pos, from, count); |
| 1160 | if (res == count) |
| 1161 | return -EFAULT; |
| 1162 | count -= res; |
| 1163 | *ppos = pos + count; |
| 1164 | return count; |
| 1165 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1166 | EXPORT_SYMBOL(simple_write_to_buffer); |
Jiri Slaby | 6a727b4 | 2010-05-01 23:51:22 +0200 | [diff] [blame] | 1167 | |
| 1168 | /** |
Akinobu Mita | 6d1029b | 2008-07-04 09:59:51 -0700 | [diff] [blame] | 1169 | * memory_read_from_buffer - copy data from the buffer |
| 1170 | * @to: the kernel space buffer to read to |
| 1171 | * @count: the maximum number of bytes to read |
| 1172 | * @ppos: the current position in the buffer |
| 1173 | * @from: the buffer to read from |
| 1174 | * @available: the size of the buffer |
| 1175 | * |
| 1176 | * The memory_read_from_buffer() function reads up to @count bytes from the |
| 1177 | * buffer @from at offset @ppos into the kernel space address starting at @to. |
| 1178 | * |
| 1179 | * On success, the number of bytes read is returned and the offset @ppos is |
| 1180 | * advanced by this number, or negative value is returned on error. |
| 1181 | **/ |
Akinobu Mita | 93b0711 | 2008-06-05 22:46:21 -0700 | [diff] [blame] | 1182 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
| 1183 | const void *from, size_t available) |
| 1184 | { |
| 1185 | loff_t pos = *ppos; |
| 1186 | |
| 1187 | if (pos < 0) |
| 1188 | return -EINVAL; |
| 1189 | if (pos >= available) |
| 1190 | return 0; |
| 1191 | if (count > available - pos) |
| 1192 | count = available - pos; |
| 1193 | memcpy(to, from + pos, count); |
| 1194 | *ppos = pos + count; |
| 1195 | |
| 1196 | return count; |
| 1197 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1198 | EXPORT_SYMBOL(memory_read_from_buffer); |
Akinobu Mita | 93b0711 | 2008-06-05 22:46:21 -0700 | [diff] [blame] | 1199 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1200 | /* |
| 1201 | * Transaction based IO. |
| 1202 | * The file expects a single write which triggers the transaction, and then |
| 1203 | * possibly a read which collects the result - which is stored in a |
| 1204 | * file-local buffer. |
| 1205 | */ |
Ingo Molnar | 76791ab | 2009-03-25 16:48:35 +0100 | [diff] [blame] | 1206 | |
| 1207 | void simple_transaction_set(struct file *file, size_t n) |
| 1208 | { |
| 1209 | struct simple_transaction_argresp *ar = file->private_data; |
| 1210 | |
| 1211 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); |
| 1212 | |
| 1213 | /* |
| 1214 | * The barrier ensures that ar->size will really remain zero until |
| 1215 | * ar->data is ready for reading. |
| 1216 | */ |
| 1217 | smp_mb(); |
| 1218 | ar->size = n; |
| 1219 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1220 | EXPORT_SYMBOL(simple_transaction_set); |
Ingo Molnar | 76791ab | 2009-03-25 16:48:35 +0100 | [diff] [blame] | 1221 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1222 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
| 1223 | { |
| 1224 | struct simple_transaction_argresp *ar; |
| 1225 | static DEFINE_SPINLOCK(simple_transaction_lock); |
| 1226 | |
| 1227 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) |
| 1228 | return ERR_PTR(-EFBIG); |
| 1229 | |
| 1230 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); |
| 1231 | if (!ar) |
| 1232 | return ERR_PTR(-ENOMEM); |
| 1233 | |
| 1234 | spin_lock(&simple_transaction_lock); |
| 1235 | |
| 1236 | /* only one write allowed per open */ |
| 1237 | if (file->private_data) { |
| 1238 | spin_unlock(&simple_transaction_lock); |
| 1239 | free_page((unsigned long)ar); |
| 1240 | return ERR_PTR(-EBUSY); |
| 1241 | } |
| 1242 | |
| 1243 | file->private_data = ar; |
| 1244 | |
| 1245 | spin_unlock(&simple_transaction_lock); |
| 1246 | |
| 1247 | if (copy_from_user(ar->data, buf, size)) |
| 1248 | return ERR_PTR(-EFAULT); |
| 1249 | |
| 1250 | return ar->data; |
| 1251 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1252 | EXPORT_SYMBOL(simple_transaction_get); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | |
| 1254 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) |
| 1255 | { |
| 1256 | struct simple_transaction_argresp *ar = file->private_data; |
| 1257 | |
| 1258 | if (!ar) |
| 1259 | return 0; |
| 1260 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); |
| 1261 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1262 | EXPORT_SYMBOL(simple_transaction_read); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1263 | |
| 1264 | int simple_transaction_release(struct inode *inode, struct file *file) |
| 1265 | { |
| 1266 | free_page((unsigned long)file->private_data); |
| 1267 | return 0; |
| 1268 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1269 | EXPORT_SYMBOL(simple_transaction_release); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1270 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1271 | /* Simple attribute files */ |
| 1272 | |
| 1273 | struct simple_attr { |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 1274 | int (*get)(void *, u64 *); |
| 1275 | int (*set)(void *, u64); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1276 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
| 1277 | char set_buf[24]; |
| 1278 | void *data; |
| 1279 | const char *fmt; /* format for read operation */ |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 1280 | struct mutex mutex; /* protects access to these buffers */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1281 | }; |
| 1282 | |
| 1283 | /* simple_attr_open is called by an actual attribute open file operation |
| 1284 | * to set the attribute specific access operations. */ |
| 1285 | int simple_attr_open(struct inode *inode, struct file *file, |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 1286 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1287 | const char *fmt) |
| 1288 | { |
| 1289 | struct simple_attr *attr; |
| 1290 | |
Eric Biggers | a65cab7 | 2020-03-07 18:38:49 -0800 | [diff] [blame] | 1291 | attr = kzalloc(sizeof(*attr), GFP_KERNEL); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1292 | if (!attr) |
| 1293 | return -ENOMEM; |
| 1294 | |
| 1295 | attr->get = get; |
| 1296 | attr->set = set; |
Theodore Ts'o | 8e18e29 | 2006-09-27 01:50:46 -0700 | [diff] [blame] | 1297 | attr->data = inode->i_private; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1298 | attr->fmt = fmt; |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 1299 | mutex_init(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1300 | |
| 1301 | file->private_data = attr; |
| 1302 | |
| 1303 | return nonseekable_open(inode, file); |
| 1304 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1305 | EXPORT_SYMBOL_GPL(simple_attr_open); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1306 | |
Christoph Hellwig | 74bedc4 | 2008-02-08 04:20:28 -0800 | [diff] [blame] | 1307 | int simple_attr_release(struct inode *inode, struct file *file) |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1308 | { |
| 1309 | kfree(file->private_data); |
| 1310 | return 0; |
| 1311 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1312 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1313 | |
| 1314 | /* read from the buffer that is filled with the get function */ |
| 1315 | ssize_t simple_attr_read(struct file *file, char __user *buf, |
| 1316 | size_t len, loff_t *ppos) |
| 1317 | { |
| 1318 | struct simple_attr *attr; |
| 1319 | size_t size; |
| 1320 | ssize_t ret; |
| 1321 | |
| 1322 | attr = file->private_data; |
| 1323 | |
| 1324 | if (!attr->get) |
| 1325 | return -EACCES; |
| 1326 | |
Christoph Hellwig | 9261303 | 2008-02-08 04:20:27 -0800 | [diff] [blame] | 1327 | ret = mutex_lock_interruptible(&attr->mutex); |
| 1328 | if (ret) |
| 1329 | return ret; |
| 1330 | |
Eric Biggers | a65cab7 | 2020-03-07 18:38:49 -0800 | [diff] [blame] | 1331 | if (*ppos && attr->get_buf[0]) { |
| 1332 | /* continued read */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1333 | size = strlen(attr->get_buf); |
Eric Biggers | a65cab7 | 2020-03-07 18:38:49 -0800 | [diff] [blame] | 1334 | } else { |
| 1335 | /* first read */ |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 1336 | u64 val; |
| 1337 | ret = attr->get(attr->data, &val); |
| 1338 | if (ret) |
| 1339 | goto out; |
| 1340 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1341 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 1342 | attr->fmt, (unsigned long long)val); |
| 1343 | } |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1344 | |
| 1345 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); |
Christoph Hellwig | 8b88b09 | 2008-02-08 04:20:26 -0800 | [diff] [blame] | 1346 | out: |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 1347 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1348 | return ret; |
| 1349 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1350 | EXPORT_SYMBOL_GPL(simple_attr_read); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1351 | |
| 1352 | /* interpret the buffer as a number to call the set function with */ |
Akinobu Mita | 2e41f27 | 2022-09-20 02:24:16 +0900 | [diff] [blame] | 1353 | static ssize_t simple_attr_write_xsigned(struct file *file, const char __user *buf, |
| 1354 | size_t len, loff_t *ppos, bool is_signed) |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1355 | { |
| 1356 | struct simple_attr *attr; |
Yicong Yang | 488dac0 | 2020-11-21 22:17:19 -0800 | [diff] [blame] | 1357 | unsigned long long val; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1358 | size_t size; |
| 1359 | ssize_t ret; |
| 1360 | |
| 1361 | attr = file->private_data; |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1362 | if (!attr->set) |
| 1363 | return -EACCES; |
| 1364 | |
Christoph Hellwig | 9261303 | 2008-02-08 04:20:27 -0800 | [diff] [blame] | 1365 | ret = mutex_lock_interruptible(&attr->mutex); |
| 1366 | if (ret) |
| 1367 | return ret; |
| 1368 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1369 | ret = -EFAULT; |
| 1370 | size = min(sizeof(attr->set_buf) - 1, len); |
| 1371 | if (copy_from_user(attr->set_buf, buf, size)) |
| 1372 | goto out; |
| 1373 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1374 | attr->set_buf[size] = '\0'; |
Akinobu Mita | 2e41f27 | 2022-09-20 02:24:16 +0900 | [diff] [blame] | 1375 | if (is_signed) |
| 1376 | ret = kstrtoll(attr->set_buf, 0, &val); |
| 1377 | else |
| 1378 | ret = kstrtoull(attr->set_buf, 0, &val); |
Yicong Yang | 488dac0 | 2020-11-21 22:17:19 -0800 | [diff] [blame] | 1379 | if (ret) |
| 1380 | goto out; |
Wu Fengguang | 05cc0ce | 2009-09-18 13:06:03 -0700 | [diff] [blame] | 1381 | ret = attr->set(attr->data, val); |
| 1382 | if (ret == 0) |
| 1383 | ret = len; /* on success, claim we got the whole input */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1384 | out: |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 1385 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1386 | return ret; |
| 1387 | } |
Akinobu Mita | 2e41f27 | 2022-09-20 02:24:16 +0900 | [diff] [blame] | 1388 | |
| 1389 | ssize_t simple_attr_write(struct file *file, const char __user *buf, |
| 1390 | size_t len, loff_t *ppos) |
| 1391 | { |
| 1392 | return simple_attr_write_xsigned(file, buf, len, ppos, false); |
| 1393 | } |
Al Viro | 12f3887 | 2013-09-15 21:20:49 -0400 | [diff] [blame] | 1394 | EXPORT_SYMBOL_GPL(simple_attr_write); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 1395 | |
Akinobu Mita | 2e41f27 | 2022-09-20 02:24:16 +0900 | [diff] [blame] | 1396 | ssize_t simple_attr_write_signed(struct file *file, const char __user *buf, |
| 1397 | size_t len, loff_t *ppos) |
| 1398 | { |
| 1399 | return simple_attr_write_xsigned(file, buf, len, ppos, true); |
| 1400 | } |
| 1401 | EXPORT_SYMBOL_GPL(simple_attr_write_signed); |
| 1402 | |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 1403 | /** |
Amir Goldstein | d9e5d92 | 2023-10-26 23:45:40 +0300 | [diff] [blame] | 1404 | * generic_encode_ino32_fh - generic export_operations->encode_fh function |
| 1405 | * @inode: the object to encode |
| 1406 | * @fh: where to store the file handle fragment |
| 1407 | * @max_len: maximum length to store there (in 4 byte units) |
| 1408 | * @parent: parent directory inode, if wanted |
| 1409 | * |
| 1410 | * This generic encode_fh function assumes that the 32 inode number |
| 1411 | * is suitable for locating an inode, and that the generation number |
| 1412 | * can be used to check that it is still valid. It places them in the |
| 1413 | * filehandle fragment where export_decode_fh expects to find them. |
| 1414 | */ |
| 1415 | int generic_encode_ino32_fh(struct inode *inode, __u32 *fh, int *max_len, |
| 1416 | struct inode *parent) |
| 1417 | { |
| 1418 | struct fid *fid = (void *)fh; |
| 1419 | int len = *max_len; |
| 1420 | int type = FILEID_INO32_GEN; |
| 1421 | |
| 1422 | if (parent && (len < 4)) { |
| 1423 | *max_len = 4; |
| 1424 | return FILEID_INVALID; |
| 1425 | } else if (len < 2) { |
| 1426 | *max_len = 2; |
| 1427 | return FILEID_INVALID; |
| 1428 | } |
| 1429 | |
| 1430 | len = 2; |
| 1431 | fid->i32.ino = inode->i_ino; |
| 1432 | fid->i32.gen = inode->i_generation; |
| 1433 | if (parent) { |
| 1434 | fid->i32.parent_ino = parent->i_ino; |
| 1435 | fid->i32.parent_gen = parent->i_generation; |
| 1436 | len = 4; |
| 1437 | type = FILEID_INO32_GEN_PARENT; |
| 1438 | } |
| 1439 | *max_len = len; |
| 1440 | return type; |
| 1441 | } |
| 1442 | EXPORT_SYMBOL_GPL(generic_encode_ino32_fh); |
| 1443 | |
| 1444 | /** |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 1445 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation |
| 1446 | * @sb: filesystem to do the file handle conversion on |
| 1447 | * @fid: file handle to convert |
| 1448 | * @fh_len: length of the file handle in bytes |
| 1449 | * @fh_type: type of file handle |
| 1450 | * @get_inode: filesystem callback to retrieve inode |
| 1451 | * |
| 1452 | * This function decodes @fid as long as it has one of the well-known |
| 1453 | * Linux filehandle types and calls @get_inode on it to retrieve the |
| 1454 | * inode for the object specified in the file handle. |
| 1455 | */ |
| 1456 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, |
| 1457 | int fh_len, int fh_type, struct inode *(*get_inode) |
| 1458 | (struct super_block *sb, u64 ino, u32 gen)) |
| 1459 | { |
| 1460 | struct inode *inode = NULL; |
| 1461 | |
| 1462 | if (fh_len < 2) |
| 1463 | return NULL; |
| 1464 | |
| 1465 | switch (fh_type) { |
| 1466 | case FILEID_INO32_GEN: |
| 1467 | case FILEID_INO32_GEN_PARENT: |
| 1468 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); |
| 1469 | break; |
| 1470 | } |
| 1471 | |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1472 | return d_obtain_alias(inode); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 1473 | } |
| 1474 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); |
| 1475 | |
| 1476 | /** |
Yanchuan Nian | ca18683 | 2012-09-05 16:31:29 +0800 | [diff] [blame] | 1477 | * 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] | 1478 | * @sb: filesystem to do the file handle conversion on |
| 1479 | * @fid: file handle to convert |
| 1480 | * @fh_len: length of the file handle in bytes |
| 1481 | * @fh_type: type of file handle |
| 1482 | * @get_inode: filesystem callback to retrieve inode |
| 1483 | * |
| 1484 | * This function decodes @fid as long as it has one of the well-known |
| 1485 | * Linux filehandle types and calls @get_inode on it to retrieve the |
| 1486 | * inode for the _parent_ object specified in the file handle if it |
| 1487 | * is specified in the file handle, or NULL otherwise. |
| 1488 | */ |
| 1489 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, |
| 1490 | int fh_len, int fh_type, struct inode *(*get_inode) |
| 1491 | (struct super_block *sb, u64 ino, u32 gen)) |
| 1492 | { |
| 1493 | struct inode *inode = NULL; |
| 1494 | |
| 1495 | if (fh_len <= 2) |
| 1496 | return NULL; |
| 1497 | |
| 1498 | switch (fh_type) { |
| 1499 | case FILEID_INO32_GEN_PARENT: |
| 1500 | inode = get_inode(sb, fid->i32.parent_ino, |
| 1501 | (fh_len > 3 ? fid->i32.parent_gen : 0)); |
| 1502 | break; |
| 1503 | } |
| 1504 | |
Christoph Hellwig | 4ea3ada | 2008-08-11 15:48:57 +0200 | [diff] [blame] | 1505 | return d_obtain_alias(inode); |
Christoph Hellwig | 2596110 | 2007-10-21 16:42:05 -0700 | [diff] [blame] | 1506 | } |
| 1507 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); |
| 1508 | |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1509 | /** |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1510 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
| 1511 | * |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1512 | * @file: file to synchronize |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1513 | * @start: start offset in bytes |
| 1514 | * @end: end offset in bytes (inclusive) |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1515 | * @datasync: only synchronize essential metadata if true |
| 1516 | * |
| 1517 | * This is a generic implementation of the fsync method for simple |
| 1518 | * filesystems which track all non-inode metadata in the buffers list |
| 1519 | * hanging off the address_space structure. |
| 1520 | */ |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1521 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
| 1522 | int datasync) |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1523 | { |
Christoph Hellwig | 7ea8085 | 2010-05-26 17:53:25 +0200 | [diff] [blame] | 1524 | struct inode *inode = file->f_mapping->host; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1525 | int err; |
| 1526 | int ret; |
| 1527 | |
Jeff Layton | 383aa54 | 2017-07-06 07:02:29 -0400 | [diff] [blame] | 1528 | err = file_write_and_wait_range(file, start, end); |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1529 | if (err) |
| 1530 | return err; |
| 1531 | |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 1532 | inode_lock(inode); |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1533 | ret = sync_mapping_buffers(inode->i_mapping); |
Theodore Ts'o | 0ae45f6 | 2015-02-02 00:37:00 -0500 | [diff] [blame] | 1534 | if (!(inode->i_state & I_DIRTY_ALL)) |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1535 | goto out; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1536 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1537 | goto out; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1538 | |
Christoph Hellwig | c3765016 | 2010-10-06 10:48:20 +0200 | [diff] [blame] | 1539 | err = sync_inode_metadata(inode, 1); |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1540 | if (ret == 0) |
| 1541 | ret = err; |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1542 | |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1543 | out: |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 1544 | inode_unlock(inode); |
Jeff Layton | 383aa54 | 2017-07-06 07:02:29 -0400 | [diff] [blame] | 1545 | /* check and advance again to catch errors after syncing out buffers */ |
| 1546 | err = file_check_and_advance_wb_err(file); |
| 1547 | if (ret == 0) |
| 1548 | ret = err; |
| 1549 | return ret; |
Al Viro | d5aacad | 2009-06-07 14:56:44 -0400 | [diff] [blame] | 1550 | } |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1551 | EXPORT_SYMBOL(__generic_file_fsync); |
| 1552 | |
| 1553 | /** |
| 1554 | * generic_file_fsync - generic fsync implementation for simple filesystems |
| 1555 | * with flush |
| 1556 | * @file: file to synchronize |
| 1557 | * @start: start offset in bytes |
| 1558 | * @end: end offset in bytes (inclusive) |
| 1559 | * @datasync: only synchronize essential metadata if true |
| 1560 | * |
| 1561 | */ |
| 1562 | |
| 1563 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, |
| 1564 | int datasync) |
| 1565 | { |
| 1566 | struct inode *inode = file->f_mapping->host; |
| 1567 | int err; |
| 1568 | |
| 1569 | err = __generic_file_fsync(file, start, end, datasync); |
| 1570 | if (err) |
| 1571 | return err; |
Christoph Hellwig | c6bf3f0 | 2021-01-26 15:52:35 +0100 | [diff] [blame] | 1572 | return blkdev_issue_flush(inode->i_sb->s_bdev); |
Fabian Frederick | ac13a82 | 2014-06-04 16:06:27 -0700 | [diff] [blame] | 1573 | } |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1574 | EXPORT_SYMBOL(generic_file_fsync); |
| 1575 | |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1576 | /** |
| 1577 | * generic_check_addressable - Check addressability of file system |
| 1578 | * @blocksize_bits: log of file system block size |
| 1579 | * @num_blocks: number of blocks in file system |
| 1580 | * |
| 1581 | * Determine whether a file system with @num_blocks blocks (and a |
| 1582 | * block size of 2**@blocksize_bits) is addressable by the sector_t |
| 1583 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. |
| 1584 | */ |
| 1585 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) |
| 1586 | { |
| 1587 | u64 last_fs_block = num_blocks - 1; |
Joel Becker | a33f13e | 2010-08-16 12:10:17 -0700 | [diff] [blame] | 1588 | u64 last_fs_page = |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 1589 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1590 | |
| 1591 | if (unlikely(num_blocks == 0)) |
| 1592 | return 0; |
| 1593 | |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 1594 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1595 | return -EINVAL; |
| 1596 | |
Joel Becker | a33f13e | 2010-08-16 12:10:17 -0700 | [diff] [blame] | 1597 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
| 1598 | (last_fs_page > (pgoff_t)(~0ULL))) { |
Patrick J. LoPresti | 30ca22c | 2010-07-22 15:03:41 -0700 | [diff] [blame] | 1599 | return -EFBIG; |
| 1600 | } |
| 1601 | return 0; |
| 1602 | } |
| 1603 | EXPORT_SYMBOL(generic_check_addressable); |
| 1604 | |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1605 | /* |
| 1606 | * No-op implementation of ->fsync for in-memory filesystems. |
| 1607 | */ |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 1608 | 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] | 1609 | { |
| 1610 | return 0; |
| 1611 | } |
Christoph Hellwig | 1b061d9 | 2010-05-26 17:53:41 +0200 | [diff] [blame] | 1612 | EXPORT_SYMBOL(noop_fsync); |
Al Viro | 87dc800 | 2013-09-16 10:30:04 -0400 | [diff] [blame] | 1613 | |
Dan Williams | f44c776 | 2018-03-07 15:26:44 -0800 | [diff] [blame] | 1614 | ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
| 1615 | { |
| 1616 | /* |
| 1617 | * iomap based filesystems support direct I/O without need for |
| 1618 | * this callback. However, it still needs to be set in |
| 1619 | * inode->a_ops so that open/fcntl know that direct I/O is |
| 1620 | * generally supported. |
| 1621 | */ |
| 1622 | return -EINVAL; |
| 1623 | } |
| 1624 | EXPORT_SYMBOL_GPL(noop_direct_IO); |
| 1625 | |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1626 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
| 1627 | void kfree_link(void *p) |
Al Viro | 87dc800 | 2013-09-16 10:30:04 -0400 | [diff] [blame] | 1628 | { |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1629 | kfree(p); |
Al Viro | 87dc800 | 2013-09-16 10:30:04 -0400 | [diff] [blame] | 1630 | } |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1631 | EXPORT_SYMBOL(kfree_link); |
Al Viro | 6987843 | 2013-10-02 22:35:11 -0400 | [diff] [blame] | 1632 | |
Al Viro | 6987843 | 2013-10-02 22:35:11 -0400 | [diff] [blame] | 1633 | struct inode *alloc_anon_inode(struct super_block *s) |
| 1634 | { |
| 1635 | static const struct address_space_operations anon_aops = { |
Matthew Wilcox (Oracle) | 46de8b97 | 2022-02-09 20:22:13 +0000 | [diff] [blame] | 1636 | .dirty_folio = noop_dirty_folio, |
Al Viro | 6987843 | 2013-10-02 22:35:11 -0400 | [diff] [blame] | 1637 | }; |
| 1638 | struct inode *inode = new_inode_pseudo(s); |
| 1639 | |
| 1640 | if (!inode) |
| 1641 | return ERR_PTR(-ENOMEM); |
| 1642 | |
| 1643 | inode->i_ino = get_next_ino(); |
| 1644 | inode->i_mapping->a_ops = &anon_aops; |
| 1645 | |
| 1646 | /* |
| 1647 | * Mark the inode dirty from the very beginning, |
| 1648 | * that way it will never be moved to the dirty |
| 1649 | * list because mark_inode_dirty() will think |
| 1650 | * that it already _is_ on the dirty list. |
| 1651 | */ |
| 1652 | inode->i_state = I_DIRTY; |
| 1653 | inode->i_mode = S_IRUSR | S_IWUSR; |
| 1654 | inode->i_uid = current_fsuid(); |
| 1655 | inode->i_gid = current_fsgid(); |
| 1656 | inode->i_flags |= S_PRIVATE; |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 1657 | simple_inode_init_ts(inode); |
Al Viro | 6987843 | 2013-10-02 22:35:11 -0400 | [diff] [blame] | 1658 | return inode; |
| 1659 | } |
| 1660 | EXPORT_SYMBOL(alloc_anon_inode); |
Jeff Layton | 1c994a0 | 2014-08-27 06:49:41 -0400 | [diff] [blame] | 1661 | |
| 1662 | /** |
| 1663 | * simple_nosetlease - generic helper for prohibiting leases |
| 1664 | * @filp: file pointer |
| 1665 | * @arg: type of lease to obtain |
| 1666 | * @flp: new lease supplied for insertion |
Jeff Layton | e6f5c78 | 2014-08-22 10:40:25 -0400 | [diff] [blame] | 1667 | * @priv: private data for lm_setup operation |
Jeff Layton | 1c994a0 | 2014-08-27 06:49:41 -0400 | [diff] [blame] | 1668 | * |
| 1669 | * Generic helper for filesystems that do not wish to allow leases to be set. |
| 1670 | * All arguments are ignored and it just returns -EINVAL. |
| 1671 | */ |
| 1672 | int |
Jeff Layton | c69ff40 | 2024-01-31 18:02:28 -0500 | [diff] [blame] | 1673 | simple_nosetlease(struct file *filp, int arg, struct file_lease **flp, |
Jeff Layton | e6f5c78 | 2014-08-22 10:40:25 -0400 | [diff] [blame] | 1674 | void **priv) |
Jeff Layton | 1c994a0 | 2014-08-27 06:49:41 -0400 | [diff] [blame] | 1675 | { |
| 1676 | return -EINVAL; |
| 1677 | } |
| 1678 | EXPORT_SYMBOL(simple_nosetlease); |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1679 | |
Eric Biggers | 6ee9706 | 2019-04-11 16:16:30 -0700 | [diff] [blame] | 1680 | /** |
| 1681 | * simple_get_link - generic helper to get the target of "fast" symlinks |
| 1682 | * @dentry: not used here |
| 1683 | * @inode: the symlink inode |
| 1684 | * @done: not used here |
| 1685 | * |
| 1686 | * Generic helper for filesystems to use for symlink inodes where a pointer to |
| 1687 | * the symlink target is stored in ->i_link. NOTE: this isn't normally called, |
| 1688 | * since as an optimization the path lookup code uses any non-NULL ->i_link |
| 1689 | * directly, without calling ->get_link(). But ->get_link() still must be set, |
| 1690 | * to mark the inode_operations as being for a symlink. |
| 1691 | * |
| 1692 | * Return: the symlink target |
| 1693 | */ |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1694 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 1695 | struct delayed_call *done) |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1696 | { |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1697 | return inode->i_link; |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1698 | } |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1699 | EXPORT_SYMBOL(simple_get_link); |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1700 | |
| 1701 | const struct inode_operations simple_symlink_inode_operations = { |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 1702 | .get_link = simple_get_link, |
Al Viro | 61ba64f | 2015-05-02 09:54:06 -0400 | [diff] [blame] | 1703 | }; |
| 1704 | EXPORT_SYMBOL(simple_symlink_inode_operations); |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1705 | |
| 1706 | /* |
| 1707 | * Operations for a permanently empty directory. |
| 1708 | */ |
| 1709 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
| 1710 | { |
| 1711 | return ERR_PTR(-ENOENT); |
| 1712 | } |
| 1713 | |
Christian Brauner | b74d24f | 2023-01-13 12:49:12 +0100 | [diff] [blame] | 1714 | static int empty_dir_getattr(struct mnt_idmap *idmap, |
Christian Brauner | 549c729 | 2021-01-21 14:19:43 +0100 | [diff] [blame] | 1715 | const struct path *path, struct kstat *stat, |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 1716 | u32 request_mask, unsigned int query_flags) |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1717 | { |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 1718 | struct inode *inode = d_inode(path->dentry); |
Jeff Layton | 0d72b928 | 2023-08-07 15:38:33 -0400 | [diff] [blame] | 1719 | generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1720 | return 0; |
| 1721 | } |
| 1722 | |
Christian Brauner | c1632a0 | 2023-01-13 12:49:11 +0100 | [diff] [blame] | 1723 | static int empty_dir_setattr(struct mnt_idmap *idmap, |
Christian Brauner | 549c729 | 2021-01-21 14:19:43 +0100 | [diff] [blame] | 1724 | struct dentry *dentry, struct iattr *attr) |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1725 | { |
| 1726 | return -EPERM; |
| 1727 | } |
| 1728 | |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1729 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) |
| 1730 | { |
| 1731 | return -EOPNOTSUPP; |
| 1732 | } |
| 1733 | |
| 1734 | static const struct inode_operations empty_dir_inode_operations = { |
| 1735 | .lookup = empty_dir_lookup, |
| 1736 | .permission = generic_permission, |
| 1737 | .setattr = empty_dir_setattr, |
| 1738 | .getattr = empty_dir_getattr, |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1739 | .listxattr = empty_dir_listxattr, |
| 1740 | }; |
| 1741 | |
| 1742 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) |
| 1743 | { |
| 1744 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ |
| 1745 | return generic_file_llseek_size(file, offset, whence, 2, 2); |
| 1746 | } |
| 1747 | |
| 1748 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) |
| 1749 | { |
| 1750 | dir_emit_dots(file, ctx); |
| 1751 | return 0; |
| 1752 | } |
| 1753 | |
| 1754 | static const struct file_operations empty_dir_operations = { |
| 1755 | .llseek = empty_dir_llseek, |
| 1756 | .read = generic_read_dir, |
Al Viro | c51da20 | 2016-04-30 22:37:34 -0400 | [diff] [blame] | 1757 | .iterate_shared = empty_dir_readdir, |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1758 | .fsync = noop_fsync, |
| 1759 | }; |
| 1760 | |
| 1761 | |
| 1762 | void make_empty_dir_inode(struct inode *inode) |
| 1763 | { |
| 1764 | set_nlink(inode, 2); |
| 1765 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; |
| 1766 | inode->i_uid = GLOBAL_ROOT_UID; |
| 1767 | inode->i_gid = GLOBAL_ROOT_GID; |
| 1768 | inode->i_rdev = 0; |
Eric W. Biederman | 4b75de86 | 2015-08-12 15:00:12 -0500 | [diff] [blame] | 1769 | inode->i_size = 0; |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1770 | inode->i_blkbits = PAGE_SHIFT; |
| 1771 | inode->i_blocks = 0; |
| 1772 | |
| 1773 | inode->i_op = &empty_dir_inode_operations; |
Andreas Gruenbacher | f5c2443 | 2016-09-29 17:48:41 +0200 | [diff] [blame] | 1774 | inode->i_opflags &= ~IOP_XATTR; |
Eric W. Biederman | fbabfd0 | 2015-05-09 15:54:49 -0500 | [diff] [blame] | 1775 | inode->i_fop = &empty_dir_operations; |
| 1776 | } |
| 1777 | |
| 1778 | bool is_empty_dir_inode(struct inode *inode) |
| 1779 | { |
| 1780 | return (inode->i_fop == &empty_dir_operations) && |
| 1781 | (inode->i_op == &empty_dir_inode_operations); |
| 1782 | } |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1783 | |
Christoph Hellwig | 5298d4b | 2022-01-18 07:56:14 +0100 | [diff] [blame] | 1784 | #if IS_ENABLED(CONFIG_UNICODE) |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1785 | /** |
| 1786 | * generic_ci_d_compare - generic d_compare implementation for casefolding filesystems |
| 1787 | * @dentry: dentry whose name we are checking against |
| 1788 | * @len: len of name of dentry |
| 1789 | * @str: str pointer to name of dentry |
| 1790 | * @name: Name to compare against |
| 1791 | * |
| 1792 | * Return: 0 if names match, 1 if mismatch, or -ERRNO |
| 1793 | */ |
Eric Biggers | 794c43f | 2020-12-28 15:25:29 -0800 | [diff] [blame] | 1794 | static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, |
| 1795 | const char *str, const struct qstr *name) |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1796 | { |
Gabriel Krisman Bertazi | 0906fbb | 2024-01-24 15:13:40 -0300 | [diff] [blame] | 1797 | const struct dentry *parent; |
| 1798 | const struct inode *dir; |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1799 | char strbuf[DNAME_INLINE_LEN]; |
Gabriel Krisman Bertazi | 0906fbb | 2024-01-24 15:13:40 -0300 | [diff] [blame] | 1800 | struct qstr qstr; |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1801 | |
Gabriel Krisman Bertazi | 0906fbb | 2024-01-24 15:13:40 -0300 | [diff] [blame] | 1802 | /* |
| 1803 | * Attempt a case-sensitive match first. It is cheaper and |
| 1804 | * should cover most lookups, including all the sane |
| 1805 | * applications that expect a case-sensitive filesystem. |
| 1806 | * |
| 1807 | * This comparison is safe under RCU because the caller |
| 1808 | * guarantees the consistency between str and len. See |
| 1809 | * __d_lookup_rcu_op_compare() for details. |
| 1810 | */ |
| 1811 | if (len == name->len && !memcmp(str, name->name, len)) |
| 1812 | return 0; |
| 1813 | |
| 1814 | parent = READ_ONCE(dentry->d_parent); |
| 1815 | dir = READ_ONCE(parent->d_inode); |
Eric Biggers | af494af | 2023-08-14 11:29:03 -0700 | [diff] [blame] | 1816 | if (!dir || !IS_CASEFOLDED(dir)) |
Gabriel Krisman Bertazi | 0906fbb | 2024-01-24 15:13:40 -0300 | [diff] [blame] | 1817 | return 1; |
| 1818 | |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1819 | /* |
| 1820 | * If the dentry name is stored in-line, then it may be concurrently |
| 1821 | * modified by a rename. If this happens, the VFS will eventually retry |
| 1822 | * the lookup, so it doesn't matter what ->d_compare() returns. |
| 1823 | * However, it's unsafe to call utf8_strncasecmp() with an unstable |
| 1824 | * string. Therefore, we have to copy the name into a temporary buffer. |
| 1825 | */ |
| 1826 | if (len <= DNAME_INLINE_LEN - 1) { |
| 1827 | memcpy(strbuf, str, len); |
| 1828 | strbuf[len] = 0; |
Gabriel Krisman Bertazi | 0906fbb | 2024-01-24 15:13:40 -0300 | [diff] [blame] | 1829 | str = strbuf; |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1830 | /* prevent compiler from optimizing out the temporary buffer */ |
| 1831 | barrier(); |
| 1832 | } |
Gabriel Krisman Bertazi | 0906fbb | 2024-01-24 15:13:40 -0300 | [diff] [blame] | 1833 | qstr.len = len; |
| 1834 | qstr.name = str; |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1835 | |
Gabriel Krisman Bertazi | 0906fbb | 2024-01-24 15:13:40 -0300 | [diff] [blame] | 1836 | return utf8_strncasecmp(dentry->d_sb->s_encoding, name, &qstr); |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1837 | } |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1838 | |
| 1839 | /** |
| 1840 | * generic_ci_d_hash - generic d_hash implementation for casefolding filesystems |
| 1841 | * @dentry: dentry of the parent directory |
| 1842 | * @str: qstr of name whose hash we should fill in |
| 1843 | * |
| 1844 | * Return: 0 if hash was successful or unchanged, and -EINVAL on error |
| 1845 | */ |
Eric Biggers | 794c43f | 2020-12-28 15:25:29 -0800 | [diff] [blame] | 1846 | static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1847 | { |
| 1848 | const struct inode *dir = READ_ONCE(dentry->d_inode); |
| 1849 | struct super_block *sb = dentry->d_sb; |
| 1850 | const struct unicode_map *um = sb->s_encoding; |
Li zeming | bae8bc4 | 2024-02-20 14:20:30 +0800 | [diff] [blame] | 1851 | int ret; |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1852 | |
Eric Biggers | af494af | 2023-08-14 11:29:03 -0700 | [diff] [blame] | 1853 | if (!dir || !IS_CASEFOLDED(dir)) |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1854 | return 0; |
| 1855 | |
| 1856 | ret = utf8_casefold_hash(um, dentry, str); |
| 1857 | if (ret < 0 && sb_has_strict_encoding(sb)) |
| 1858 | return -EINVAL; |
| 1859 | return 0; |
| 1860 | } |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1861 | |
| 1862 | static const struct dentry_operations generic_ci_dentry_ops = { |
| 1863 | .d_hash = generic_ci_d_hash, |
| 1864 | .d_compare = generic_ci_d_compare, |
Gabriel Krisman Bertazi | e6ca288 | 2024-02-21 12:14:07 -0500 | [diff] [blame] | 1865 | #ifdef CONFIG_FS_ENCRYPTION |
| 1866 | .d_revalidate = fscrypt_d_revalidate, |
| 1867 | #endif |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1868 | }; |
Gabriel Krisman Bertazi | 6a79a4e | 2024-06-06 10:33:49 +0300 | [diff] [blame] | 1869 | |
| 1870 | /** |
| 1871 | * generic_ci_match() - Match a name (case-insensitively) with a dirent. |
| 1872 | * This is a filesystem helper for comparison with directory entries. |
| 1873 | * generic_ci_d_compare should be used in VFS' ->d_compare instead. |
| 1874 | * |
| 1875 | * @parent: Inode of the parent of the dirent under comparison |
| 1876 | * @name: name under lookup. |
| 1877 | * @folded_name: Optional pre-folded name under lookup |
| 1878 | * @de_name: Dirent name. |
| 1879 | * @de_name_len: dirent name length. |
| 1880 | * |
| 1881 | * Test whether a case-insensitive directory entry matches the filename |
| 1882 | * being searched. If @folded_name is provided, it is used instead of |
| 1883 | * recalculating the casefold of @name. |
| 1884 | * |
| 1885 | * Return: > 0 if the directory entry matches, 0 if it doesn't match, or |
| 1886 | * < 0 on error. |
| 1887 | */ |
| 1888 | int generic_ci_match(const struct inode *parent, |
| 1889 | const struct qstr *name, |
| 1890 | const struct qstr *folded_name, |
| 1891 | const u8 *de_name, u32 de_name_len) |
| 1892 | { |
| 1893 | const struct super_block *sb = parent->i_sb; |
| 1894 | const struct unicode_map *um = sb->s_encoding; |
| 1895 | struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len); |
| 1896 | struct qstr dirent = QSTR_INIT(de_name, de_name_len); |
| 1897 | int res = 0; |
| 1898 | |
| 1899 | if (IS_ENCRYPTED(parent)) { |
| 1900 | const struct fscrypt_str encrypted_name = |
| 1901 | FSTR_INIT((u8 *) de_name, de_name_len); |
| 1902 | |
| 1903 | if (WARN_ON_ONCE(!fscrypt_has_encryption_key(parent))) |
| 1904 | return -EINVAL; |
| 1905 | |
| 1906 | decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); |
| 1907 | if (!decrypted_name.name) |
| 1908 | return -ENOMEM; |
| 1909 | res = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, |
| 1910 | &decrypted_name); |
| 1911 | if (res < 0) { |
| 1912 | kfree(decrypted_name.name); |
| 1913 | return res; |
| 1914 | } |
| 1915 | dirent.name = decrypted_name.name; |
| 1916 | dirent.len = decrypted_name.len; |
| 1917 | } |
| 1918 | |
| 1919 | /* |
| 1920 | * Attempt a case-sensitive match first. It is cheaper and |
| 1921 | * should cover most lookups, including all the sane |
| 1922 | * applications that expect a case-sensitive filesystem. |
| 1923 | */ |
| 1924 | |
| 1925 | if (dirent.len == name->len && |
| 1926 | !memcmp(name->name, dirent.name, dirent.len)) |
| 1927 | goto out; |
| 1928 | |
| 1929 | if (folded_name->name) |
| 1930 | res = utf8_strncasecmp_folded(um, folded_name, &dirent); |
| 1931 | else |
| 1932 | res = utf8_strncasecmp(um, name, &dirent); |
| 1933 | |
| 1934 | out: |
| 1935 | kfree(decrypted_name.name); |
| 1936 | if (res < 0 && sb_has_strict_encoding(sb)) { |
| 1937 | pr_err_ratelimited("Directory contains filename that is invalid UTF-8"); |
| 1938 | return 0; |
| 1939 | } |
| 1940 | return !res; |
| 1941 | } |
| 1942 | EXPORT_SYMBOL(generic_ci_match); |
Daniel Rosenberg | c843843 | 2020-07-08 02:12:35 -0700 | [diff] [blame] | 1943 | #endif |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1944 | |
| 1945 | #ifdef CONFIG_FS_ENCRYPTION |
| 1946 | static const struct dentry_operations generic_encrypted_dentry_ops = { |
| 1947 | .d_revalidate = fscrypt_d_revalidate, |
| 1948 | }; |
| 1949 | #endif |
| 1950 | |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1951 | /** |
Gabriel Krisman Bertazi | 70dfe3f | 2024-02-21 12:14:08 -0500 | [diff] [blame] | 1952 | * generic_set_sb_d_ops - helper for choosing the set of |
| 1953 | * filesystem-wide dentry operations for the enabled features |
| 1954 | * @sb: superblock to be configured |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1955 | * |
Gabriel Krisman Bertazi | 70dfe3f | 2024-02-21 12:14:08 -0500 | [diff] [blame] | 1956 | * Filesystems supporting casefolding and/or fscrypt can call this |
| 1957 | * helper at mount-time to configure sb->s_d_op to best set of dentry |
| 1958 | * operations required for the enabled features. The helper must be |
| 1959 | * called after these have been configured, but before the root dentry |
| 1960 | * is created. |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1961 | */ |
Gabriel Krisman Bertazi | 70dfe3f | 2024-02-21 12:14:08 -0500 | [diff] [blame] | 1962 | void generic_set_sb_d_ops(struct super_block *sb) |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1963 | { |
Christoph Hellwig | 5298d4b | 2022-01-18 07:56:14 +0100 | [diff] [blame] | 1964 | #if IS_ENABLED(CONFIG_UNICODE) |
Gabriel Krisman Bertazi | 70dfe3f | 2024-02-21 12:14:08 -0500 | [diff] [blame] | 1965 | if (sb->s_encoding) { |
| 1966 | sb->s_d_op = &generic_ci_dentry_ops; |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1967 | return; |
| 1968 | } |
| 1969 | #endif |
| 1970 | #ifdef CONFIG_FS_ENCRYPTION |
Gabriel Krisman Bertazi | 70dfe3f | 2024-02-21 12:14:08 -0500 | [diff] [blame] | 1971 | if (sb->s_cop) { |
| 1972 | sb->s_d_op = &generic_encrypted_dentry_ops; |
Daniel Rosenberg | 608af70 | 2020-11-19 06:09:02 +0000 | [diff] [blame] | 1973 | return; |
| 1974 | } |
| 1975 | #endif |
| 1976 | } |
Gabriel Krisman Bertazi | 70dfe3f | 2024-02-21 12:14:08 -0500 | [diff] [blame] | 1977 | EXPORT_SYMBOL(generic_set_sb_d_ops); |
Andrew Morton | 5ca1483 | 2022-09-09 13:57:41 -0700 | [diff] [blame] | 1978 | |
| 1979 | /** |
| 1980 | * inode_maybe_inc_iversion - increments i_version |
| 1981 | * @inode: inode with the i_version that should be updated |
| 1982 | * @force: increment the counter even if it's not necessary? |
| 1983 | * |
| 1984 | * Every time the inode is modified, the i_version field must be seen to have |
| 1985 | * changed by any observer. |
| 1986 | * |
| 1987 | * If "force" is set or the QUERIED flag is set, then ensure that we increment |
| 1988 | * the value, and clear the queried flag. |
| 1989 | * |
| 1990 | * In the common case where neither is set, then we can return "false" without |
| 1991 | * updating i_version. |
| 1992 | * |
| 1993 | * If this function returns false, and no other metadata has changed, then we |
| 1994 | * can avoid logging the metadata. |
| 1995 | */ |
| 1996 | bool inode_maybe_inc_iversion(struct inode *inode, bool force) |
| 1997 | { |
| 1998 | u64 cur, new; |
| 1999 | |
| 2000 | /* |
| 2001 | * The i_version field is not strictly ordered with any other inode |
| 2002 | * information, but the legacy inode_inc_iversion code used a spinlock |
| 2003 | * to serialize increments. |
| 2004 | * |
Mateusz Guzik | b381fbb | 2024-08-15 10:33:10 +0200 | [diff] [blame] | 2005 | * We add a full memory barrier to ensure that any de facto ordering |
| 2006 | * with other state is preserved (either implicitly coming from cmpxchg |
| 2007 | * or explicitly from smp_mb if we don't know upfront if we will execute |
| 2008 | * the former). |
Andrew Morton | 5ca1483 | 2022-09-09 13:57:41 -0700 | [diff] [blame] | 2009 | * |
Mateusz Guzik | b381fbb | 2024-08-15 10:33:10 +0200 | [diff] [blame] | 2010 | * These barriers pair with inode_query_iversion(). |
Andrew Morton | 5ca1483 | 2022-09-09 13:57:41 -0700 | [diff] [blame] | 2011 | */ |
Andrew Morton | 5ca1483 | 2022-09-09 13:57:41 -0700 | [diff] [blame] | 2012 | cur = inode_peek_iversion_raw(inode); |
Mateusz Guzik | b381fbb | 2024-08-15 10:33:10 +0200 | [diff] [blame] | 2013 | if (!force && !(cur & I_VERSION_QUERIED)) { |
| 2014 | smp_mb(); |
| 2015 | cur = inode_peek_iversion_raw(inode); |
| 2016 | } |
| 2017 | |
Andrew Morton | 5ca1483 | 2022-09-09 13:57:41 -0700 | [diff] [blame] | 2018 | do { |
| 2019 | /* If flag is clear then we needn't do anything */ |
| 2020 | if (!force && !(cur & I_VERSION_QUERIED)) |
| 2021 | return false; |
| 2022 | |
| 2023 | /* Since lowest bit is flag, add 2 to avoid it */ |
| 2024 | new = (cur & ~I_VERSION_QUERIED) + I_VERSION_INCREMENT; |
| 2025 | } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); |
| 2026 | return true; |
| 2027 | } |
| 2028 | EXPORT_SYMBOL(inode_maybe_inc_iversion); |
Jeff Layton | c5bc1b3 | 2022-09-16 09:37:51 -0400 | [diff] [blame] | 2029 | |
| 2030 | /** |
| 2031 | * inode_query_iversion - read i_version for later use |
| 2032 | * @inode: inode from which i_version should be read |
| 2033 | * |
| 2034 | * Read the inode i_version counter. This should be used by callers that wish |
| 2035 | * to store the returned i_version for later comparison. This will guarantee |
| 2036 | * that a later query of the i_version will result in a different value if |
| 2037 | * anything has changed. |
| 2038 | * |
| 2039 | * In this implementation, we fetch the current value, set the QUERIED flag and |
| 2040 | * then try to swap it into place with a cmpxchg, if it wasn't already set. If |
| 2041 | * that fails, we try again with the newly fetched value from the cmpxchg. |
| 2042 | */ |
| 2043 | u64 inode_query_iversion(struct inode *inode) |
| 2044 | { |
| 2045 | u64 cur, new; |
Mateusz Guzik | b381fbb | 2024-08-15 10:33:10 +0200 | [diff] [blame] | 2046 | bool fenced = false; |
Jeff Layton | c5bc1b3 | 2022-09-16 09:37:51 -0400 | [diff] [blame] | 2047 | |
Mateusz Guzik | b381fbb | 2024-08-15 10:33:10 +0200 | [diff] [blame] | 2048 | /* |
| 2049 | * Memory barriers (implicit in cmpxchg, explicit in smp_mb) pair with |
| 2050 | * inode_maybe_inc_iversion(), see that routine for more details. |
| 2051 | */ |
Jeff Layton | c5bc1b3 | 2022-09-16 09:37:51 -0400 | [diff] [blame] | 2052 | cur = inode_peek_iversion_raw(inode); |
| 2053 | do { |
| 2054 | /* If flag is already set, then no need to swap */ |
| 2055 | if (cur & I_VERSION_QUERIED) { |
Mateusz Guzik | b381fbb | 2024-08-15 10:33:10 +0200 | [diff] [blame] | 2056 | if (!fenced) |
| 2057 | smp_mb(); |
Jeff Layton | c5bc1b3 | 2022-09-16 09:37:51 -0400 | [diff] [blame] | 2058 | break; |
| 2059 | } |
| 2060 | |
Mateusz Guzik | b381fbb | 2024-08-15 10:33:10 +0200 | [diff] [blame] | 2061 | fenced = true; |
Jeff Layton | c5bc1b3 | 2022-09-16 09:37:51 -0400 | [diff] [blame] | 2062 | new = cur | I_VERSION_QUERIED; |
| 2063 | } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); |
| 2064 | return cur >> I_VERSION_QUERIED_SHIFT; |
| 2065 | } |
| 2066 | EXPORT_SYMBOL(inode_query_iversion); |
Christoph Hellwig | 44fff0f | 2023-06-01 16:59:01 +0200 | [diff] [blame] | 2067 | |
| 2068 | ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, |
| 2069 | ssize_t direct_written, ssize_t buffered_written) |
| 2070 | { |
| 2071 | struct address_space *mapping = iocb->ki_filp->f_mapping; |
| 2072 | loff_t pos = iocb->ki_pos - buffered_written; |
| 2073 | loff_t end = iocb->ki_pos - 1; |
| 2074 | int err; |
| 2075 | |
| 2076 | /* |
| 2077 | * If the buffered write fallback returned an error, we want to return |
| 2078 | * the number of bytes which were written by direct I/O, or the error |
| 2079 | * code if that was zero. |
| 2080 | * |
| 2081 | * Note that this differs from normal direct-io semantics, which will |
| 2082 | * return -EFOO even if some bytes were written. |
| 2083 | */ |
| 2084 | if (unlikely(buffered_written < 0)) { |
| 2085 | if (direct_written) |
| 2086 | return direct_written; |
| 2087 | return buffered_written; |
| 2088 | } |
| 2089 | |
| 2090 | /* |
| 2091 | * We need to ensure that the page cache pages are written to disk and |
| 2092 | * invalidated to preserve the expected O_DIRECT semantics. |
| 2093 | */ |
| 2094 | err = filemap_write_and_wait_range(mapping, pos, end); |
| 2095 | if (err < 0) { |
| 2096 | /* |
| 2097 | * We don't know how much we wrote, so just return the number of |
| 2098 | * bytes which were direct-written |
| 2099 | */ |
Al Viro | 8287474 | 2023-09-13 18:28:15 +0200 | [diff] [blame] | 2100 | iocb->ki_pos -= buffered_written; |
Christoph Hellwig | 44fff0f | 2023-06-01 16:59:01 +0200 | [diff] [blame] | 2101 | if (direct_written) |
| 2102 | return direct_written; |
| 2103 | return err; |
| 2104 | } |
| 2105 | invalidate_mapping_pages(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT); |
| 2106 | return direct_written + buffered_written; |
| 2107 | } |
| 2108 | EXPORT_SYMBOL_GPL(direct_write_fallback); |
Jeff Layton | 077c212 | 2023-10-04 14:52:37 -0400 | [diff] [blame] | 2109 | |
| 2110 | /** |
| 2111 | * simple_inode_init_ts - initialize the timestamps for a new inode |
| 2112 | * @inode: inode to be initialized |
| 2113 | * |
| 2114 | * When a new inode is created, most filesystems set the timestamps to the |
| 2115 | * current time. Add a helper to do this. |
| 2116 | */ |
| 2117 | struct timespec64 simple_inode_init_ts(struct inode *inode) |
| 2118 | { |
| 2119 | struct timespec64 ts = inode_set_ctime_current(inode); |
| 2120 | |
| 2121 | inode_set_atime_to_ts(inode, ts); |
| 2122 | inode_set_mtime_to_ts(inode, ts); |
| 2123 | return ts; |
| 2124 | } |
| 2125 | EXPORT_SYMBOL(simple_inode_init_ts); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2126 | |
Christian Brauner | 4e32c25 | 2024-09-06 18:22:22 +0200 | [diff] [blame] | 2127 | static inline struct dentry *get_stashed_dentry(struct dentry **stashed) |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2128 | { |
| 2129 | struct dentry *dentry; |
| 2130 | |
| 2131 | guard(rcu)(); |
Christian Brauner | 4e32c25 | 2024-09-06 18:22:22 +0200 | [diff] [blame] | 2132 | dentry = rcu_dereference(*stashed); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2133 | if (!dentry) |
| 2134 | return NULL; |
| 2135 | if (!lockref_get_not_dead(&dentry->d_lockref)) |
| 2136 | return NULL; |
| 2137 | return dentry; |
| 2138 | } |
| 2139 | |
Christian Brauner | 2558e3b | 2024-02-21 09:59:51 +0100 | [diff] [blame] | 2140 | static struct dentry *prepare_anon_dentry(struct dentry **stashed, |
Christian Brauner | 159a0d9 | 2024-02-18 14:52:24 +0100 | [diff] [blame] | 2141 | struct super_block *sb, |
Christian Brauner | 159a0d9 | 2024-02-18 14:52:24 +0100 | [diff] [blame] | 2142 | void *data) |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2143 | { |
| 2144 | struct dentry *dentry; |
| 2145 | struct inode *inode; |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2146 | const struct stashed_operations *sops = sb->s_fs_info; |
Christian Brauner | 9d9539d | 2024-03-12 10:39:44 +0100 | [diff] [blame] | 2147 | int ret; |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2148 | |
| 2149 | inode = new_inode_pseudo(sb); |
| 2150 | if (!inode) { |
Christian Brauner | 9d9539d | 2024-03-12 10:39:44 +0100 | [diff] [blame] | 2151 | sops->put_data(data); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2152 | return ERR_PTR(-ENOMEM); |
| 2153 | } |
| 2154 | |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2155 | inode->i_flags |= S_IMMUTABLE; |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2156 | inode->i_mode = S_IFREG; |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2157 | simple_inode_init_ts(inode); |
Christian Brauner | 9d9539d | 2024-03-12 10:39:44 +0100 | [diff] [blame] | 2158 | |
| 2159 | ret = sops->init_inode(inode, data); |
| 2160 | if (ret < 0) { |
| 2161 | iput(inode); |
| 2162 | return ERR_PTR(ret); |
| 2163 | } |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2164 | |
| 2165 | /* Notice when this is changed. */ |
| 2166 | WARN_ON_ONCE(!S_ISREG(inode->i_mode)); |
| 2167 | WARN_ON_ONCE(!IS_IMMUTABLE(inode)); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2168 | |
Christian Brauner | 9d9539d | 2024-03-12 10:39:44 +0100 | [diff] [blame] | 2169 | dentry = d_alloc_anon(sb); |
| 2170 | if (!dentry) { |
| 2171 | iput(inode); |
| 2172 | return ERR_PTR(-ENOMEM); |
| 2173 | } |
| 2174 | |
Christian Brauner | 2558e3b | 2024-02-21 09:59:51 +0100 | [diff] [blame] | 2175 | /* Store address of location where dentry's supposed to be stashed. */ |
| 2176 | dentry->d_fsdata = stashed; |
| 2177 | |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2178 | /* @data is now owned by the fs */ |
| 2179 | d_instantiate(dentry, inode); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2180 | return dentry; |
| 2181 | } |
| 2182 | |
Christian Brauner | 159a0d9 | 2024-02-18 14:52:24 +0100 | [diff] [blame] | 2183 | static struct dentry *stash_dentry(struct dentry **stashed, |
| 2184 | struct dentry *dentry) |
| 2185 | { |
| 2186 | guard(rcu)(); |
| 2187 | for (;;) { |
| 2188 | struct dentry *old; |
| 2189 | |
| 2190 | /* Assume any old dentry was cleared out. */ |
| 2191 | old = cmpxchg(stashed, NULL, dentry); |
| 2192 | if (likely(!old)) |
| 2193 | return dentry; |
| 2194 | |
| 2195 | /* Check if somebody else installed a reusable dentry. */ |
| 2196 | if (lockref_get_not_dead(&old->d_lockref)) |
| 2197 | return old; |
| 2198 | |
| 2199 | /* There's an old dead dentry there, try to take it over. */ |
| 2200 | if (likely(try_cmpxchg(stashed, &old, dentry))) |
| 2201 | return dentry; |
| 2202 | } |
| 2203 | } |
| 2204 | |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2205 | /** |
| 2206 | * path_from_stashed - create path from stashed or new dentry |
| 2207 | * @stashed: where to retrieve or stash dentry |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2208 | * @mnt: mnt of the filesystems to use |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2209 | * @data: data to store in inode->i_private |
| 2210 | * @path: path to create |
| 2211 | * |
| 2212 | * The function tries to retrieve a stashed dentry from @stashed. If the dentry |
| 2213 | * is still valid then it will be reused. If the dentry isn't able the function |
Christian Brauner | 159a0d9 | 2024-02-18 14:52:24 +0100 | [diff] [blame] | 2214 | * will allocate a new dentry and inode. It will then check again whether it |
| 2215 | * can reuse an existing dentry in case one has been added in the meantime or |
| 2216 | * update @stashed with the newly added dentry. |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2217 | * |
| 2218 | * Special-purpose helper for nsfs and pidfs. |
| 2219 | * |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2220 | * Return: On success zero and on failure a negative error is returned. |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2221 | */ |
Christian Brauner | 9d9539d | 2024-03-12 10:39:44 +0100 | [diff] [blame] | 2222 | int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, |
| 2223 | struct path *path) |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2224 | { |
| 2225 | struct dentry *dentry; |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2226 | const struct stashed_operations *sops = mnt->mnt_sb->s_fs_info; |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2227 | |
Christian Brauner | 159a0d9 | 2024-02-18 14:52:24 +0100 | [diff] [blame] | 2228 | /* See if dentry can be reused. */ |
Christian Brauner | 4e32c25 | 2024-09-06 18:22:22 +0200 | [diff] [blame] | 2229 | path->dentry = get_stashed_dentry(stashed); |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2230 | if (path->dentry) { |
| 2231 | sops->put_data(data); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2232 | goto out_path; |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2233 | } |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2234 | |
Christian Brauner | 159a0d9 | 2024-02-18 14:52:24 +0100 | [diff] [blame] | 2235 | /* Allocate a new dentry. */ |
Christian Brauner | 9d9539d | 2024-03-12 10:39:44 +0100 | [diff] [blame] | 2236 | dentry = prepare_anon_dentry(stashed, mnt->mnt_sb, data); |
| 2237 | if (IS_ERR(dentry)) |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2238 | return PTR_ERR(dentry); |
Christian Brauner | 159a0d9 | 2024-02-18 14:52:24 +0100 | [diff] [blame] | 2239 | |
| 2240 | /* Added a new dentry. @data is now owned by the filesystem. */ |
| 2241 | path->dentry = stash_dentry(stashed, dentry); |
| 2242 | if (path->dentry != dentry) |
| 2243 | dput(dentry); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2244 | |
| 2245 | out_path: |
Christian Brauner | 2558e3b | 2024-02-21 09:59:51 +0100 | [diff] [blame] | 2246 | WARN_ON_ONCE(path->dentry->d_fsdata != stashed); |
| 2247 | WARN_ON_ONCE(d_inode(path->dentry)->i_private != data); |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2248 | path->mnt = mntget(mnt); |
Christian Brauner | e9c5263 | 2024-03-01 10:26:03 +0100 | [diff] [blame] | 2249 | return 0; |
Christian Brauner | 07fd7c3 | 2024-02-18 14:50:13 +0100 | [diff] [blame] | 2250 | } |
Christian Brauner | 2558e3b | 2024-02-21 09:59:51 +0100 | [diff] [blame] | 2251 | |
| 2252 | void stashed_dentry_prune(struct dentry *dentry) |
| 2253 | { |
| 2254 | struct dentry **stashed = dentry->d_fsdata; |
| 2255 | struct inode *inode = d_inode(dentry); |
| 2256 | |
| 2257 | if (WARN_ON_ONCE(!stashed)) |
| 2258 | return; |
| 2259 | |
| 2260 | if (!inode) |
| 2261 | return; |
| 2262 | |
| 2263 | /* |
| 2264 | * Only replace our own @dentry as someone else might've |
| 2265 | * already cleared out @dentry and stashed their own |
| 2266 | * dentry in there. |
| 2267 | */ |
| 2268 | cmpxchg(stashed, dentry, NULL); |
| 2269 | } |