linux/fs
Filipe Manana 357950361c btrfs: set last dir index to the current last index when opening dir
When opening a directory for reading it, we set the last index where we
stop iteration to the value in struct btrfs_inode::index_cnt. That value
does not match the index of the most recently added directory entry but
it's instead the index number that will be assigned the next directory
entry.

This means that if after the call to opendir(3) new directory entries are
added, a readdir(3) call will return the first new directory entry. This
is fine because POSIX says the following [1]:

  "If a file is removed from or added to the directory after the most
   recent call to opendir() or rewinddir(), whether a subsequent call to
   readdir() returns an entry for that file is unspecified."

For example for the test script from commit 9b378f6ad4 ("btrfs: fix
infinite directory reads"), where we have 2000 files in a directory, ext4
doesn't return any new directory entry after opendir(3), while xfs returns
the first 13 new directory entries added after the opendir(3) call.

If we move to a shorter example with an empty directory when opendir(3) is
called, and 2 files added to the directory after the opendir(3) call, then
readdir(3) on btrfs will return the first file, ext4 and xfs return the 2
files (but in a different order). A test program for this, reported by
Ian Johnson, is the following:

   #include <dirent.h>
   #include <stdio.h>

   int main(void) {
     DIR *dir = opendir("test");

     FILE *file;
     file = fopen("test/1", "w");
     fwrite("1", 1, 1, file);
     fclose(file);

     file = fopen("test/2", "w");
     fwrite("2", 1, 1, file);
     fclose(file);

     struct dirent *entry;
     while ((entry = readdir(dir))) {
        printf("%s\n", entry->d_name);
     }
     closedir(dir);
     return 0;
   }

To make this less odd, change the behaviour to never return new entries
that were added after the opendir(3) call. This is done by setting the
last_index field of the struct btrfs_file_private attached to the
directory's file handle with a value matching btrfs_inode::index_cnt
minus 1, since that value always matches the index of the next new
directory entry and not the index of the most recently added entry.

[1] https://pubs.opengroup.org/onlinepubs/007904875/functions/readdir_r.html

Link: https://lore.kernel.org/linux-btrfs/YR1P0S.NGASEG570GJ8@ianjohnson.dev/
CC: stable@vger.kernel.org # 6.5+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-09-14 23:24:42 +02:00
..
9p fs/9p: Remove unused extern declaration 2023-07-20 19:21:48 +00:00
adfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
affs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
afs afs: Fix accidental truncation when storing data 2023-07-04 12:24:32 -07:00
autofs arch/*/configs/*defconfig: Replace AUTOFS4_FS by AUTOFS_FS 2023-07-29 14:08:22 -07:00
befs befs: Replace all non-returning strlcpy with strscpy 2023-05-30 16:42:00 -07:00
bfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
btrfs btrfs: set last dir index to the current last index when opening dir 2023-09-14 23:24:42 +02:00
cachefiles v6.5/vfs.file 2023-06-26 10:14:36 -07:00
ceph vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
coda vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
configfs fs: consolidate duplicate dt_type helpers 2023-04-03 09:23:54 +02:00
cramfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
crypto fscrypt: Replace 1-element array with flexible array 2023-05-23 19:46:09 -07:00
debugfs debugfs: Correct the 'debugfs_create_str' docs 2023-05-31 19:02:14 +01:00
devpts devpts: simplify two-level sysctl registration for pty_kern_table 2023-03-13 12:36:34 +01:00
dlm dlm for 6.5 2023-06-29 13:27:50 -07:00
ecryptfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
efivarfs efivarfs: expose used and total size 2023-05-17 18:21:34 +02:00
efs
erofs erofs: drop unnecessary WARN_ON() in erofs_kill_sb() 2023-08-01 16:12:24 +08:00
exfat vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
exportfs vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
ext2 \n 2023-06-29 13:39:51 -07:00
ext4 ext4: fix rbtree traversal bug in ext4_mb_use_preallocated 2023-07-23 08:21:14 -04:00
f2fs f2fs update for 6.5-rc1 2023-07-05 14:14:37 -07:00
fat splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
freevxfs There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
fscache fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work() 2023-01-30 12:51:54 +00:00
fuse fuse update for 6.5 2023-07-19 11:00:27 -07:00
gfs2 gfs2: Don't use filemap_splice_read 2023-08-07 18:42:04 +02:00
hfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
hfsplus splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
hostfs Landlock updates for v6.5-rc1 2023-06-27 17:10:27 -07:00
hpfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
hugetlbfs hugetlb: revert use of page_cache_next_miss() 2023-06-23 16:59:32 -07:00
iomap iomap: micro optimize the ki_pos assignment in iomap_file_buffered_write 2023-07-17 08:49:57 -07:00
isofs
jbd2 jbd2: remove __journal_try_to_free_buffer() 2023-07-10 23:09:21 -04:00
jffs2 for-6.5/splice-2023-06-23 2023-06-26 11:52:12 -07:00
jfs vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
kernfs driver core changes for 6.5-rc1 2023-07-03 12:56:23 -07:00
lockd NFS client updates for Linux 6.5 2023-07-01 14:38:25 -07:00
minix splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
netfs Move netfs_extract_iter_to_sg() to lib/scatterlist.c 2023-06-08 13:42:33 +02:00
nfs NFS client updates for Linux 6.5 2023-07-01 14:38:25 -07:00
nfs_common NFSv4.2: remove MODULE_LICENSE in non-modules 2023-04-13 13:13:52 -07:00
nfsd nfsd-6.5 fixes: 2023-08-03 09:26:34 -07:00
nilfs2 nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput 2023-08-04 13:03:43 -07:00
nls fs/nls: make load_nls() take a const parameter 2023-07-25 00:30:02 -05:00
notify fanotify: disallow mount/sb marks on kernel internal pseudo fs 2023-07-04 13:29:29 +02:00
ntfs vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
ntfs3 driver ntfs3 for linux 6.5 2023-07-07 14:59:38 -07:00
ocfs2 vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
omfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
openpromfs
orangefs orangefs: Provide a splice-read wrapper 2023-05-24 08:42:16 -06:00
overlayfs vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
proc 14 hotfixes. 11 of these are cc:stable and the remainder address post-6.4 2023-08-11 14:19:20 -07:00
pstore pstore updates for v6.5-rc1 2023-06-27 21:21:32 -07:00
qnx4 qnx4: credit contributors in CREDITS 2023-03-14 12:56:30 -06:00
qnx6 qnx6: credit contributor and mark filesystem orphan 2023-03-14 12:56:30 -06:00
quota quota: fix warning in dqgrab() 2023-06-05 16:50:30 +02:00
ramfs - Yosry Ahmed brought back some cgroup v1 stats in OOM logs. 2023-06-28 10:28:11 -07:00
reiserfs - Yosry Ahmed brought back some cgroup v1 stats in OOM logs. 2023-06-28 10:28:11 -07:00
romfs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
smb smb: client: fix null auth 2023-08-16 00:26:07 -05:00
squashfs squashfs: fix cache race with migration 2023-07-08 09:29:30 -07:00
sysfs sysfs: Skip empty folders creation 2023-06-15 13:37:53 +02:00
sysv for-6.5/splice-2023-06-23 2023-06-26 11:52:12 -07:00
tracefs fs: port ->mkdir() to pass mnt_idmap 2023-01-19 09:24:26 +01:00
ubifs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
udf \n 2023-06-29 13:39:51 -07:00
ufs splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
unicode unicode: remove MODULE_LICENSE in non-modules 2023-04-13 13:13:54 -07:00
vboxsf hardening fixes for v6.5-rc6 2023-08-08 14:59:49 -07:00
verity fsverity: improve documentation for builtin signature support 2023-06-20 22:47:55 -07:00
xfs xfs: convert flex-array declarations in xfs attr shortform objects 2023-07-17 08:48:56 -07:00
zonefs zonefs: fix synchronous direct writes to sequential files 2023-08-10 12:59:47 +09:00
aio.c fs/aio: Stop allocating aio rings from HIGHMEM 2023-06-15 09:22:23 +02:00
anon_inodes.c
attr.c nfs: use vfs setgid helper 2023-03-30 08:51:48 +02:00
bad_inode.c fs: port ->permission() to pass mnt_idmap 2023-01-19 09:24:28 +01:00
binfmt_elf.c Merge branch 'expand-stack' 2023-06-28 20:35:21 -07:00
binfmt_elf_fdpic.c binfmt: Slightly simplify elf_fdpic_map_file() 2023-05-30 15:49:46 -07:00
binfmt_elf_test.c
binfmt_flat.c
binfmt_misc.c binfmt_misc: fix shift-out-of-bounds in check_special_flags 2022-12-02 13:57:04 -08:00
binfmt_script.c
buffer.c \n 2023-06-29 13:39:51 -07:00
char_dev.c vfs: Replace all non-returning strlcpy with strscpy 2023-05-15 09:42:01 +02:00
compat_binfmt_elf.c
coredump.c v6.5/vfs.misc 2023-06-26 09:50:21 -07:00
d_path.c fs: d_path: include internal.h 2023-05-17 09:16:59 +02:00
dax.c dax: enable dax fault handler to report VM_FAULT_HWPOISON 2023-06-26 07:54:23 -06:00
dcache.c
direct-io.c - Yosry Ahmed brought back some cgroup v1 stats in OOM logs. 2023-06-28 10:28:11 -07:00
drop_caches.c
eventfd.c eventfd: show the EFD_SEMAPHORE flag in fdinfo 2023-06-15 09:22:23 +02:00
eventpoll.c v6.5/vfs.misc 2023-06-26 09:50:21 -07:00
exec.c \n 2023-06-29 13:31:44 -07:00
fcntl.c fs.idmapped.v6.3 2023-02-20 11:53:11 -08:00
fhandle.c fsnotify: move fsnotify_open() hook into do_dentry_open() 2023-06-12 10:43:45 +02:00
file.c fs: rely on ->iterate_shared to determine f_pos locking 2023-08-06 15:08:36 +02:00
file_table.c fs: move cleanup from init_file() into its callers 2023-07-02 13:15:49 +02:00
filesystems.c
fs-writeback.c writeback: move wb_over_bg_thresh() call outside lock section 2023-06-09 16:25:14 -07:00
fs_context.c fs: avoid empty option when generating legacy mount string 2023-06-07 21:49:55 +02:00
fs_parser.c ext4: journal_path mount options should follow links 2022-12-01 10:46:54 -05:00
fs_pin.c
fs_struct.c
fs_types.c
fsopen.c
init.c fs: port ->permission() to pass mnt_idmap 2023-01-19 09:24:28 +01:00
inode.c locking: remove spin_lock_prefetch 2023-08-12 09:18:47 -07:00
internal.h v6.5/vfs.file 2023-06-26 10:14:36 -07:00
ioctl.c fs: port inode_owner_or_capable() to mnt_idmap 2023-01-19 09:24:29 +01:00
Kconfig smb: move client and server files to common directory fs/smb 2023-05-24 16:29:21 -05:00
Kconfig.binfmt
kernel_read_file.c
libfs.c fs: factor out a direct_write_fallback helper 2023-06-09 16:25:53 -07:00
locks.c filelocks: use mount idmapping for setlease permission check 2023-03-09 22:36:12 +01:00
Makefile for-6.5/block-2023-06-23 2023-06-26 12:47:20 -07:00
mbcache.c ext4: fix deadlock due to mbcache entry corruption 2022-12-08 21:49:25 -05:00
mnt_idmapping.c fs: move mnt_idmap 2023-01-19 09:24:30 +01:00
mount.h
mpage.c mpage: use folios in bio end_io handler 2023-04-18 16:30:02 -07:00
namei.c fs: no need to check source 2023-07-04 10:20:29 +02:00
namespace.c v6.5/vfs.mount 2023-06-26 10:27:04 -07:00
nsfs.c kill the last remaining user of proc_ns_fget() 2023-04-20 22:55:35 -04:00
open.c open: make RESOLVE_CACHED correctly test for O_TMPFILE 2023-08-06 15:08:35 +02:00
pipe.c pipe: check for IOCB_NOWAIT alongside O_NONBLOCK 2023-05-12 17:17:27 +02:00
pnode.c fs: allow to mount beneath top mount 2023-05-19 04:30:22 +02:00
pnode.h fs: allow to mount beneath top mount 2023-05-19 04:30:22 +02:00
posix_acl.c acl: don't depend on IOP_XATTR 2023-03-06 09:59:20 +01:00
proc_namespace.c tty, proc, kernfs, random: Use copy_splice_read() 2023-05-24 08:42:16 -06:00
read_write.c splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-05-24 08:42:17 -06:00
readdir.c vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
remap_range.c fs: use UB-safe check for signed addition overflow in remap_verify_area 2023-05-24 11:03:59 +02:00
select.c
seq_file.c use less confusing names for iov_iter direction initializers 2022-11-25 13:01:55 -05:00
signalfd.c
splice.c splice, net: Fix splice_to_socket() for O_NONBLOCK socket 2023-07-26 21:56:06 -07:00
stack.c
stat.c fs.idmapped.v6.3 2023-02-20 11:53:11 -08:00
statfs.c statfs: enforce statfs[64] structure initialization 2023-05-17 15:20:17 +02:00
super.c \n 2023-06-29 13:39:51 -07:00
sync.c
sysctls.c sysctl: Refactor base paths registrations 2023-05-23 21:43:26 -07:00
timerfd.c
userfaultfd.c Merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes. 2023-06-23 16:58:19 -07:00
utimes.c fs.idmapped.v6.3 2023-02-20 11:53:11 -08:00
xattr.c fs: don't call posix_acl_listxattr in generic_listxattr 2023-05-17 15:25:20 +02:00