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android_kernel_xiaomi_sm8450/fs
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Filipe Manana 6fc9e5866c btrfs: fix race between swap file activation and snapshot creation 
commit dd0734f2a866f9d619d4abf97c3d71bcdee40ea9 upstream.

When creating a snapshot we check if the current number of swap files, in
the root, is non-zero, and if it is, we error out and warn that we can not
create the snapshot because there are active swap files.

However this is racy because when a task started activation of a swap
file, another task might have started already snapshot creation and might
have seen the counter for the number of swap files as zero. This means
that after the swap file is activated we may end up with a snapshot of the
same root successfully created, and therefore when the first write to the
swap file happens it has to fall back into COW mode, which should never
happen for active swap files.

Basically what can happen is:

1) Task A starts snapshot creation and enters ioctl.c:create_snapshot().
   There it sees that root->nr_swapfiles has a value of 0 so it continues;

2) Task B enters btrfs_swap_activate(). It is not aware that another task
   started snapshot creation but it did not finish yet. It increments
   root->nr_swapfiles from 0 to 1;

3) Task B checks that the file meets all requirements to be an active
   swap file - it has NOCOW set, there are no snapshots for the inode's
   root at the moment, no file holes, no reflinked extents, etc;

4) Task B returns success and now the file is an active swap file;

5) Task A commits the transaction to create the snapshot and finishes.
   The swap file's extents are now shared between the original root and
   the snapshot;

6) A write into an extent of the swap file is attempted - there is a
   snapshot of the file's root, so we fall back to COW mode and therefore
   the physical location of the extent changes on disk.

So fix this by taking the snapshot lock during swap file activation before
locking the extent range, as that is the order in which we lock these
during buffered writes.

Fixes: ed46ff3d42 ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-09 11:11:11 +01:00
..
9p fs: 9p: add generic splice_write file operation 2020-12-01 21:40:47 +01:00
adfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
affs fs/affs: release old buffer head on error path 2021-03-04 11:38:37 +01:00
afs rxrpc: Fix deadlock around release of dst cached on udp tunnel 2021-02-10 09:29:13 +01:00
autofs autofs: harden ioctl table 2020-10-16 11:11:22 -07:00
befs [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
bfs bfs: don't use WARNING: string when it's just info. 2021-01-06 14:56:52 +01:00
btrfs btrfs: fix race between swap file activation and snapshot creation 2021-03-09 11:11:11 +01:00
cachefiles cachefiles: Drop superfluous readpages aops NULL check 2021-01-27 11:55:22 +01:00
ceph ceph: fix flush_snap logic after putting caps 2021-03-04 11:38:08 +01:00
cifs cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting cifs_sb->prepath. 2021-02-26 10:13:01 +01:00
coda
configfs fs: configfs: delete repeated words in comments 2020-10-16 11:11:19 -07:00
cramfs [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
crypto fscrypt: add fscrypt_is_nokey_name() 2020-12-26 16:02:43 +01:00
debugfs debugfs: do not attempt to create a new file before the filesystem is initalized 2021-03-04 11:37:17 +01:00
devpts
dlm networking changes for the 5.10 merge window 2020-10-15 18:42:13 -07:00
ecryptfs mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
efivarfs efivarfs: revert "fix memory leak in efivarfs_create()" 2020-11-25 16:55:02 +01:00
efs [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
erofs erofs: fix shift-out-of-bounds of blkszbits 2021-03-07 12:34:05 +01:00
exfat exfat: fix shift-out-of-bounds in exfat_fill_super() 2021-03-04 11:38:41 +01:00
exportfs
ext2 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
ext4 ext: EXT4_KUNIT_TESTS should depend on EXT4_FS instead of selecting it 2021-03-04 11:38:15 +01:00
f2fs f2fs: fix to set/clear I_LINKABLE under i_lock 2021-03-07 12:34:12 +01:00
fat [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
freevxfs
fscache Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-06-03 16:27:18 -07:00
fuse fuse: fix bad inode 2021-01-09 13:46:24 +01:00
gfs2 gfs2: Recursive gfs2_quota_hold in gfs2_iomap_end 2021-03-04 11:38:44 +01:00
hfs fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
hfsplus fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
hostfs
hpfs [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
hugetlbfs mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page 2021-02-10 09:29:20 +01:00
iomap iomap: clean up writeback state logic on writepage error 2020-11-04 08:52:46 -08:00
isofs isofs: release buffer head before return 2021-03-04 11:38:00 +01:00
jbd2 jbd2: fix kernel-doc markups 2020-11-19 22:38:29 -05:00
jffs2 jffs2: fix use after free in jffs2_sum_write_data() 2021-03-04 11:37:51 +01:00
jfs JFS: more checks for invalid superblock 2021-03-07 12:34:04 +01:00
kernfs kernfs: wire up ->splice_read and ->splice_write 2021-01-27 11:55:29 +01:00
lockd lockd: don't use interval-based rebinding over TCP 2020-12-30 11:53:30 +01:00
minix [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
nfs NFSv4: Fixes for nfs4_bitmask_adjust() 2021-03-04 11:38:20 +01:00
nfs_common nfs_common: need lock during iterate through the list 2020-12-30 11:53:45 +01:00
nfsd nfsd: register pernet ops last, unregister first 2021-03-04 11:38:07 +01:00
nilfs2 nilfs2: make splice write available again 2021-02-13 13:55:16 +01:00
nls treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
notify fanotify: Fix sys_fanotify_mark() on native x86-32 2021-01-17 14:16:59 +01:00
ntfs ntfs: check for valid standard information attribute 2021-02-26 10:13:00 +01:00
ocfs2 ocfs2: fix a use after free on error 2021-03-04 11:38:18 +01:00
omfs fs: omfs: use kmemdup() rather than kmalloc+memcpy 2020-09-22 23:39:45 -04:00
openpromfs
orangefs orangefs: remove unnecessary assignment to variable ret 2020-08-04 15:01:58 -04:00
overlayfs ovl: expand warning in ovl_d_real() 2021-02-17 11:02:30 +01:00
proc proc: don't allow async path resolution of /proc/thread-self components 2021-03-04 11:38:42 +01:00
pstore pstore: Fix typo in compression option name 2021-03-04 11:38:33 +01:00
qnx4 [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
qnx6 [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
quota quota: Fix memory leak when handling corrupted quota file 2021-03-04 11:37:53 +01:00
ramfs ramfs: fix nommu mmap with gaps in the page cache 2020-10-16 11:11:22 -07:00
reiserfs reiserfs: add check for an invalid ih_entry_count 2021-01-06 14:56:52 +01:00
romfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
squashfs squashfs: add more sanity checks in xattr id lookup 2021-02-13 13:55:19 +01:00
sysfs sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output 2020-10-02 12:02:30 +02:00
sysv [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
tracefs
ubifs ubifs: Fix error return code in alloc_wbufs() 2021-03-04 11:37:51 +01:00
udf udf: fix the problem that the disc content is not displayed 2021-02-07 15:37:15 +01:00
ufs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
unicode unicode: Add utf8_casefold_hash 2020-09-10 14:03:31 -07:00
vboxsf Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2020-10-15 15:11:56 -07:00
verity fs-verity: use smp_load_acquire() for ->i_verity_info 2020-07-21 16:02:41 -07:00
xfs xfs: Fix assert failure in xfs_setattr_size() 2021-03-07 12:34:05 +01:00
zonefs zonefs: Fix file size of zones in full condition 2021-03-04 11:38:41 +01:00
aio.c vfs: separate __sb_start_write into blocking and non-blocking helpers 2020-11-10 16:53:07 -08:00
anon_inodes.c
attr.c
bad_inode.c fs: move the fiemap definitions out of fs.h 2020-06-03 23:16:55 -04:00
binfmt_aout.c
binfmt_elf_fdpic.c binfmt_elf, binfmt_elf_fdpic: use a VMA list snapshot 2020-10-16 11:11:21 -07:00
binfmt_elf.c fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
binfmt_em86.c Merge branch 'akpm' (patches from Andrew) 2020-06-04 19:18:29 -07:00
binfmt_flat.c binfmt_flat: revert "binfmt_flat: don't offset the data start" 2020-08-24 08:49:13 +10:00
binfmt_misc.c Merge branch 'akpm' (patches from Andrew) 2020-06-04 19:18:29 -07:00
binfmt_script.c Merge branch 'akpm' (patches from Andrew) 2020-06-04 19:18:29 -07:00
block_dev.c Revert "block: simplify set_init_blocksize" to regain lost performance 2021-02-03 23:28:45 +01:00
buffer.c mm, memcg: rework remote charging API to support nesting 2020-10-18 09:27:09 -07:00
char_dev.c
compat_binfmt_elf.c Split the old READ_IMPLIES_EXEC workaround from executable PT_GNU_STACK 2020-06-05 13:45:21 -07:00
coredump.c coredump: fix core_pattern parse error 2020-12-06 10:19:07 -08:00
d_path.c fs: fix NULL dereference due to data race in prepend_path() 2020-10-14 14:54:45 -07:00
dax.c mm: provide a saner PTE walking API for modules 2021-02-26 10:13:01 +01:00
dcache.c vfs: Use sequence counter with associated spinlock 2020-07-29 16:14:27 +02:00
dcookies.c
direct-io.c \n 2020-10-15 15:03:10 -07:00
drop_caches.c
eventfd.c
eventpoll.c kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE 2021-03-04 11:38:41 +01:00
exec.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
fcntl.c fcntl: Fix potential deadlock in send_sig{io, urg}() 2021-01-06 14:56:53 +01:00
fhandle.c
file_table.c task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
file.c kernel/io_uring: cancel io_uring before task works 2021-01-30 13:55:18 +01:00
filesystems.c
fs_context.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
fs_parser.c fs_parse: mark fs_param_bad_value() as static 2020-10-13 18:38:27 -07:00
fs_pin.c
fs_struct.c vfs: Use sequence counter with associated spinlock 2020-07-29 16:14:27 +02:00
fs_types.c
fs-writeback.c fs: fix lazytime expiration handling in __writeback_single_inode() 2021-01-27 11:54:53 +01:00
fsopen.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
init.c init: add an init_dup helper 2020-08-04 21:02:38 -04:00
inode.c fs: Handle I_DONTCACHE in iput_final() instead of generic_drop_inode() 2020-12-30 11:53:49 +01:00
internal.h fs: remove compat_sys_mount 2020-09-22 23:45:57 -04:00
io_uring.c io_uring: fix possible deadlock in io_uring_poll 2021-03-04 11:37:49 +01:00
io-wq.c io_uring: always batch cancel in *cancel_files() 2021-02-13 13:54:56 +01:00
io-wq.h io_uring: always batch cancel in *cancel_files() 2021-02-13 13:54:56 +01:00
ioctl.c fs: remove ksys_ioctl 2020-07-31 08:16:01 +02:00
Kconfig tmpfs: disallow CONFIG_TMPFS_INODE64 on alpha 2021-02-17 11:02:21 +01:00
Kconfig.binfmt treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
kernel_read_file.c fs/kernel_file_read: Add "offset" arg for partial reads 2020-10-05 13:37:04 +02:00
libfs.c libfs: fix error cast of negative value in simple_attr_write() 2020-11-22 10:48:22 -08:00
locks.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
Makefile Refactored code for 5.10: 2020-10-23 11:33:41 -07:00
mbcache.c
mount.h
mpage.c fs: convert mpage_readpages to mpage_readahead 2020-06-02 10:59:07 -07:00
namei.c fs: make unlazy_walk() error handling consistent 2021-03-07 12:34:11 +01:00
namespace.c umount(2): move the flag validity checks first 2021-01-19 18:27:32 +01:00
no-block.c
nsfs.c
open.c openat2: reject RESOLVE_BENEATH|RESOLVE_IN_ROOT 2020-12-30 11:54:24 +01:00
pipe.c fs/pipe: allow sendfile() to pipe again 2021-01-27 11:55:29 +01:00
pnode.c
pnode.h fs/namespace.c: WARN if mnt_count has become negative 2021-01-06 14:56:54 +01:00
posix_acl.c vfs: clean up posix_acl_permission() logic aroudn MAY_NOT_BLOCK 2020-06-08 11:04:19 -07:00
proc_namespace.c proc mountinfo: make splice available again 2020-12-30 11:54:02 +01:00
read_write.c Refactored code for 5.10: 2020-10-23 11:33:41 -07:00
readdir.c fs: remove ksys_getdents64 2020-07-31 08:16:00 +02:00
remap_range.c vfs: move the remap range helpers to remap_range.c 2020-10-15 09:48:49 -07:00
select.c poll: fix performance regression due to out-of-line __put_user() 2021-01-19 18:27:27 +01:00
seq_file.c fix return values of seq_read_iter() 2020-11-15 22:12:53 -05:00
signalfd.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
splice.c io_uring-5.10-2020-10-24 2020-10-24 12:40:18 -07:00
stack.c
stat.c fs: remove KSTAT_QUERY_FLAGS 2020-09-26 22:55:05 -04:00
statfs.c Add a "nosymfollow" mount option. 2020-08-27 16:06:47 -04:00
super.c vfs: move __sb_{start,end}_write* to fs.h 2020-11-10 16:53:11 -08:00
sync.c overlayfs update for 5.8 2020-06-09 15:40:50 -07:00
timerfd.c
userfaultfd.c mm: remove the now-unnecessary mmget_still_valid() hack 2020-10-16 11:11:22 -07:00
utimes.c fs: expose utimes_common 2020-07-31 08:16:01 +02:00
xattr.c fs/xattr.c: fix kernel-doc warnings for setxattr & removexattr 2020-10-13 18:38:27 -07:00