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Filipe Manana 28553fa992 Btrfs: fix race between shrinking truncate and fiemap 
When there is a fiemap executing in parallel with a shrinking truncate
we can end up in a situation where we have extent maps for which we no
longer have corresponding file extent items. This is generally harmless
and at the moment the only consequences are missing file extent items
representing holes after we expand the file size again after the
truncate operation removed the prealloc extent items, and stale
information for future fiemap calls (reporting extents that no longer
exist or may have been reallocated to other files for example).

Consider the following example:

1) Our inode has a size of 128KiB, one 128KiB extent at file offset 0
   and a 1MiB prealloc extent at file offset 128KiB;

2) Task A starts doing a shrinking truncate of our inode to reduce it to
   a size of 64KiB. Before it searches the subvolume tree for file
   extent items to delete, it drops all the extent maps in the range
   from 64KiB to (u64)-1 by calling btrfs_drop_extent_cache();

3) Task B starts doing a fiemap against our inode. When looking up for
   the inode's extent maps in the range from 128KiB to (u64)-1, it
   doesn't find any in the inode's extent map tree, since they were
   removed by task A.  Because it didn't find any in the extent map
   tree, it scans the inode's subvolume tree for file extent items, and
   it finds the 1MiB prealloc extent at file offset 128KiB, then it
   creates an extent map based on that file extent item and adds it to
   inode's extent map tree (this ends up being done by
   btrfs_get_extent() <- btrfs_get_extent_fiemap() <-
   get_extent_skip_holes());

4) Task A then drops the prealloc extent at file offset 128KiB and
   shrinks the 128KiB extent file offset 0 to a length of 64KiB. The
   truncation operation finishes and we end up with an extent map
   representing a 1MiB prealloc extent at file offset 128KiB, despite we
   don't have any more that extent;

After this the two types of problems we have are:

1) Future calls to fiemap always report that a 1MiB prealloc extent
   exists at file offset 128KiB. This is stale information, no longer
   correct;

2) If the size of the file is increased, by a truncate operation that
   increases the file size or by a write into a file offset > 64KiB for
   example, we end up not inserting file extent items to represent holes
   for any range between 128KiB and 128KiB + 1MiB, since the hole
   expansion function, btrfs_cont_expand() will skip hole insertion for
   any range for which an extent map exists that represents a prealloc
   extent. This causes fsck to complain about missing file extent items
   when not using the NO_HOLES feature.

The second issue could be often triggered by test case generic/561 from
fstests, which runs fsstress and duperemove in parallel, and duperemove
does frequent fiemap calls.

Essentially the problems happens because fiemap does not acquire the
inode's lock while truncate does, and fiemap locks the file range in the
inode's iotree while truncate does not. So fix the issue by making
btrfs_truncate_inode_items() lock the file range from the new file size
to (u64)-1, so that it serializes with fiemap.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
 		2020-02-12 17:17:10 +01:00
..
9p 9p pull request for inclusion in 5.4 2019-09-27 15:10:34 -07:00
adfs Merge branch 'work.adfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 11:33:22 -07:00
affs affs: fix a memory leak in affs_remount 2019-11-18 14:26:43 +01:00
afs Merge branch 'dhowells' (patches from DavidH) 2020-01-14 09:56:31 -08:00
autofs Merge branch 'next.autofs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-12-05 17:11:48 -08:00
befs fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
bfs fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
btrfs Btrfs: fix race between shrinking truncate and fiemap 2020-02-12 17:17:10 +01:00
cachefiles treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
ceph ceph: add more debug info when decoding mdsmap 2019-12-09 20:55:10 +01:00
cifs cifs: Optimize readdir on reparse points 2019-12-23 09:04:44 -06:00
coda y2038: add inode timestamp clamping 2019-09-19 09:42:37 -07:00
configfs configfs: calculate the depth of parent item 2019-11-06 18:36:01 +01:00
cramfs cramfs: fix usage on non-MTD device 2019-11-23 21:44:49 -05:00
crypto treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
debugfs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-12-06 09:06:58 -08:00
devpts devpts_pty_kill(): don't bother with d_delete() 2019-09-03 09:30:56 -04:00
dlm dlm for 5.3 2019-07-12 17:37:53 -07:00
ecryptfs compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
efivarfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
efs fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
erofs Changes since last update: 2019-12-11 12:25:32 -08:00
exportfs race in exportfs_decode_fh() 2019-11-11 09:21:59 -05:00
ext2 \n 2019-11-30 11:16:07 -08:00
ext4 Ext4 bug fixes (including a regression fix) for 5.5 2019-12-22 10:41:48 -08:00
f2fs compat_ioctl: remove most of fs/compat_ioctl.c 2019-12-01 13:46:15 -08:00
fat compat_ioctl: move drivers to compat_ptr_ioctl 2019-10-23 17:23:43 +02:00
freevxfs fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
fscache Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
fuse fuse: fix fuse_send_readpages() in the syncronous read case 2020-01-16 11:09:36 +01:00
gfs2 GFS2 changes for this merge window: 2019-12-05 13:20:11 -08:00
hfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
hfsplus fs/hfsplus/xattr.c: replace strncpy with memcpy 2019-07-16 19:23:23 -07:00
hostfs This pull request contains the following changes for UML: 2019-05-12 17:52:13 -04:00
hpfs fs: compat_ioctl: move FITRIM emulation into file systems 2019-10-23 17:23:46 +02:00
hugetlbfs mm/hugetlbfs: fix for_each_hstate() loop in init_hugetlbfs_fs() 2020-01-03 10:39:08 -08:00
iomap iomap: stop using ioend after it's been freed in iomap_finish_ioend() 2019-12-05 07:41:16 -08:00
isofs y2038: add inode timestamp clamping 2019-09-19 09:42:37 -07:00
jbd2 This merge window saw the the following new featuers added to ext4: 2019-11-30 10:53:02 -08:00
jffs2 Revert "jffs2: Fix possible null-pointer dereferences in jffs2_add_frag_to_fragtree()" 2019-11-29 11:29:58 +01:00
jfs y2038: add inode timestamp clamping 2019-09-19 09:42:37 -07:00
kernfs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-12-06 09:06:58 -08:00
lockd NFSv4.1: Don't rebind to the same source port when reconnecting to the server 2019-11-03 21:28:45 -05:00
minix fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
nfs reimplement path_mountpoint() with less magic 2020-01-15 01:36:06 -05:00
nfs_common treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
nfsd This is a relatively quiet cycle for nfsd, mainly various bugfixes. 2019-12-07 16:56:00 -08:00
nilfs2 fs: compat_ioctl: move FITRIM emulation into file systems 2019-10-23 17:23:46 +02:00
nls treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
notify fs: call fsnotify_sb_delete after evict_inodes 2019-12-18 00:03:01 -05:00
ntfs ntfs: remove (un)?likely() from IS_ERR() conditions 2019-09-26 10:10:44 -07:00
ocfs2 ocfs2: fix the crash due to call ocfs2_get_dlm_debug once less 2020-01-04 13:55:09 -08:00
omfs fs: omfs: Initialize filesystem timestamp ranges 2019-08-30 08:11:25 -07:00
openpromfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
orangefs orangefs: posix open permission checking... 2019-12-04 08:52:55 -05:00
overlayfs overlayfs fixes for 5.5-rc2 2019-12-14 11:13:54 -08:00
proc sched/cputime, proc/stat: Fix incorrect guest nice cpustat value 2019-12-11 07:09:58 +01:00
pstore pstore/ram: Regularize prz label allocation lifetime 2020-01-08 17:05:45 -08:00
qnx4 fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
qnx6 fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
quota fs: avoid softlockups in s_inodes iterators 2019-12-18 00:03:01 -05:00
ramfs vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API 2019-09-12 21:05:34 -04:00
reiserfs reiserfs: replace open-coded atomic_dec_and_mutex_lock() 2019-11-05 12:25:22 +01:00
romfs Merge branch 'work.mount2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-09-19 10:06:57 -07:00
squashfs Merge branch 'work.mount2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-09-19 10:06:57 -07:00
sysfs Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
sysv fs: sysv: Initialize filesystem timestamp ranges 2019-08-30 07:27:18 -07:00
tracefs tracing: Do not create tracefs files if tracefs lockdown is in effect 2019-10-12 20:49:07 -04:00
ubifs ubifs: ubifs_tnc_start_commit: Fix OOB in layout_in_gaps 2019-11-17 22:22:54 +01:00
udf fs-udf: Delete an unnecessary check before brelse() 2019-09-04 18:19:43 +02:00
ufs y2038: add inode timestamp clamping 2019-09-19 09:42:37 -07:00
unicode unicode: make array 'token' static const, makes object smaller 2019-09-17 11:48:24 -04:00
verity treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
xfs xfs: Make the symbol 'xfs_rtalloc_log_count' static 2019-12-20 08:07:31 -08:00
Kconfig io-wq: small threadpool implementation for io_uring 2019-10-29 12:43:00 -06:00
Kconfig.binfmt binfmt_flat: make support for old format binaries optional 2019-06-24 09:16:47 +10:00
Makefile io-wq: small threadpool implementation for io_uring 2019-10-29 12:43:00 -06:00
aio.c y2038: syscall implementation cleanups 2019-12-01 14:00:59 -08:00
anon_inodes.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
attr.c timestamp_truncate: Replace users of timespec64_trunc 2019-08-30 07:27:17 -07:00
bad_inode.c
…
binfmt_aout.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
binfmt_elf.c fs/binfmt_elf.c: extract elf_read() function 2019-12-04 19:44:13 -08:00
binfmt_elf_fdpic.c y2038: elfcore: Use __kernel_old_timeval for process times 2019-11-15 14:38:29 +01:00
binfmt_em86.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
binfmt_flat.c fs/binfmt_flat.c: remove set but not used variable 'inode' 2019-07-16 19:23:22 -07:00
binfmt_misc.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
binfmt_script.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
block_dev.c block: don't send uevent for empty disk when not invalidating 2019-12-02 18:49:30 -07:00
buffer.c fs: move guard_bio_eod() after bio_set_op_attrs 2020-01-09 08:16:12 -07:00
char_dev.c chardev: Avoid potential use-after-free in 'chrdev_open()' 2020-01-06 20:10:26 +01:00
compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
compat_binfmt_elf.c y2038: elfcore: Use __kernel_old_timeval for process times 2019-11-15 14:38:29 +01:00
compat_ioctl.c New code for 5.5: 2019-12-02 14:46:22 -08:00
coredump.c coredump: split pipe command whitespace before expanding template 2019-08-03 07:02:01 -07:00
d_path.c [PATCH] fix d_absolute_path() interplay with fsmount() 2019-08-30 19:31:09 -04:00
dax.c New code for 5.5: 2019-11-30 10:44:49 -08:00
dcache.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-12-08 11:08:28 -08:00
dcookies.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
direct-io.c fs/direct-io.c: include fs/internal.h for missing prototype 2020-01-04 13:55:09 -08:00
drop_caches.c fs: avoid softlockups in s_inodes iterators 2019-12-18 00:03:01 -05:00
eventfd.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
eventpoll.c fs/epoll: remove unnecessary wakeups of nested epoll 2019-12-04 19:44:13 -08:00
exec.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-12-03 12:20:25 -08:00
fcntl.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-12-08 11:08:28 -08:00
fhandle.c fs/handle.c - fix up kerneldoc 2019-08-07 21:51:47 -04:00
file.c Revert "fs: remove ksys_dup()" 2020-01-02 16:15:33 -08:00
file_table.c vfs: Export flush_delayed_fput for use by knfsd. 2019-08-19 11:00:39 -04:00
filesystems.c vfs: Implement a filesystem superblock creation/configuration context 2019-02-28 03:29:26 -05:00
fs-writeback.c cgroup,writeback: don't switch wbs immediately on dead wbs if the memcg is dead 2019-11-08 13:37:24 -07:00
fs_context.c vfs: subtype handling moved to fuse 2019-09-06 21:28:49 +02:00
fs_parser.c vfs: Make fs_parse() handle fs_param_is_fd-type params better 2019-09-12 21:06:14 -04:00
fs_pin.c switch the remnants of releasing the mountpoint away from fs_pin 2019-07-16 22:52:37 -04:00
fs_struct.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
fs_types.c fs: common implementation of file type 2019-01-21 17:48:13 +01:00
fsopen.c Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
inode.c fs: avoid softlockups in s_inodes iterators 2019-12-18 00:03:01 -05:00
internal.h fs: move guard_bio_eod() after bio_set_op_attrs 2020-01-09 08:16:12 -07:00
io-wq.c io-wq: cancel work if we fail getting a mm reference 2020-01-14 22:06:11 -07:00
io-wq.h io-wq: re-add io_wq_current_is_worker() 2019-12-17 19:57:20 -07:00
io_uring.c io_uring: only allow submit from owning task 2020-01-16 21:43:24 -07:00
ioctl.c New code for 5.5: 2019-12-02 14:46:22 -08:00
libfs.c fs/libfs.c: fix kernel-doc warning 2019-10-14 15:04:01 -07:00
locks.c locks: print unsigned ino in /proc/locks 2019-12-29 09:00:58 -05:00
mbcache.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
mount.h switch the remnants of releasing the mountpoint away from fs_pin 2019-07-16 22:52:37 -04:00
mpage.c fs: move guard_bio_eod() after bio_set_op_attrs 2020-01-09 08:16:12 -07:00
namei.c fix autofs regression caused by follow_managed() changes 2020-01-15 01:36:46 -05:00
namespace.c fs/namespace.c: make to_mnt_ns() static 2020-01-04 13:55:09 -08:00
no-block.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
nsfs.c fs/nsfs.c: include headers for missing declarations 2020-01-04 13:55:09 -08:00
open.c Revert "vfs: properly and reliably lock f_pos in fdget_pos()" 2019-11-26 11:34:06 -08:00
pipe.c pipe: fix empty pipe check in pipe_write() 2019-12-22 09:47:47 -08:00
pnode.c fs/namespace: fix unprivileged mount propagation 2019-06-17 17:36:09 -04:00
pnode.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 209 2019-05-30 11:29:53 -07:00
posix_acl.c fs/posix_acl.c: fix kernel-doc warnings 2020-01-04 13:55:09 -08:00
proc_namespace.c vfs: subtype handling moved to fuse 2019-09-06 21:28:49 +02:00
read_write.c vfs: fix page locking deadlocks when deduping files 2019-08-16 18:43:24 -07:00
readdir.c filldir[64]: remove WARN_ON_ONCE() for bad directory entries 2019-10-18 18:41:16 -04:00
select.c y2038: syscalls: change remaining timeval to __kernel_old_timeval 2019-11-15 14:38:29 +01:00
seq_file.c seq_file: fix problem when seeking mid-record 2019-08-13 16:06:52 -07:00
signalfd.c fs: mark expected switch fall-throughs 2019-04-08 18:21:02 -05:00
splice.c pipe: remove 'waiting_writers' merging logic 2019-12-07 13:21:01 -08:00
stack.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
stat.c fs: move generic stat response attr handling to vfs_getattr_nosec 2019-02-01 01:55:45 -05:00
statfs.c vfs: Fix EOVERFLOW testing in put_compat_statfs64 2019-10-03 14:21:35 -07:00
super.c fs: call fsnotify_sb_delete after evict_inodes 2019-12-18 00:03:01 -05:00
sync.c fs/sync.c: sync_file_range(2) may use WB_SYNC_ALL writeback 2019-05-14 09:47:50 -07:00
timerfd.c y2038: timerfd: Use timespec64 internally 2019-11-15 14:38:30 +01:00
userfaultfd.c Merge branch 'akpm' (patches from Andrew) 2019-12-01 20:36:41 -08:00
utimes.c y2038: syscalls: change remaining timeval to __kernel_old_timeval 2019-11-15 14:38:29 +01:00
xattr.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00