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651740a502
linux/fs
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Josef Bacik 651740a502 btrfs: check WRITE_ERR when trying to read an extent buffer 
Filipe reported a hang when we have errors on btrfs.  This turned out to
be a side-effect of my fix c2e3930529 ("btrfs: clear extent buffer
uptodate when we fail to write it") which made it so we clear
EXTENT_BUFFER_UPTODATE on an eb when we fail to write it out.

Below is a paste of Filipe's analysis he got from using drgn to debug
the hang

"""
btree readahead code calls read_extent_buffer_pages(), sets ->io_pages to
a value while writeback of all pages has not yet completed:
   --> writeback for the first 3 pages finishes, we clear
       EXTENT_BUFFER_UPTODATE from eb on the first page when we get an
       error.
   --> at this point eb->io_pages is 1 and we cleared Uptodate bit from the
       first 3 pages
   --> read_extent_buffer_pages() does not see EXTENT_BUFFER_UPTODATE() so
       it continues, it's able to lock the pages since we obviously don't
       hold the pages locked during writeback
   --> read_extent_buffer_pages() then computes 'num_reads' as 3, and sets
       eb->io_pages to 3, since only the first page does not have Uptodate
       bit set at this point
   --> writeback for the remaining page completes, we ended decrementing
       eb->io_pages by 1, resulting in eb->io_pages == 2, and therefore
       never calling end_extent_buffer_writeback(), so
       EXTENT_BUFFER_WRITEBACK remains in the eb's flags
   --> of course, when the read bio completes, it doesn't and shouldn't
       call end_extent_buffer_writeback()
   --> we should clear EXTENT_BUFFER_UPTODATE only after all pages of
       the eb finished writeback?  or maybe make the read pages code
       wait for writeback of all pages of the eb to complete before
       checking which pages need to be read, touch ->io_pages, submit
       read bio, etc

writeback bit never cleared means we can hang when aborting a
transaction, at:

    btrfs_cleanup_one_transaction()
       btrfs_destroy_marked_extents()
         wait_on_extent_buffer_writeback()
"""

This is a problem because our writes are not synchronized with reads in
any way.  We clear the UPTODATE flag and then we can easily come in and
try to read the EB while we're still waiting on other bio's to
complete.

We have two options here, we could lock all the pages, and then check to
see if eb->io_pages != 0 to know if we've already got an outstanding
write on the eb.

Or we can simply check to see if we have WRITE_ERR set on this extent
buffer.  We set this bit _before_ we clear UPTODATE, so if the read gets
triggered because we aren't UPTODATE because of a write error we're
guaranteed to have WRITE_ERR set, and in this case we can simply return
-EIO.  This will fix the reported hang.

Reported-by: Filipe Manana <fdmanana@suse.com>
Fixes: c2e3930529 ("btrfs: clear extent buffer uptodate when we fail to write it")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-12-15 17:07:31 +01:00
..
9p 9p: Fix a bunch of kerneldoc warnings shown up by W=1 2021-10-04 22:07:46 +01:00
adfs mm: require ->set_page_dirty to be explicitly wired up 2021-06-29 10:53:48 -07:00
affs mm: require ->set_page_dirty to be explicitly wired up 2021-06-29 10:53:48 -07:00
afs netfslib, cachefiles and afs fixes 2021-10-07 11:20:08 -07:00
autofs autofs: fix wait name hash calculation in autofs_wait() 2021-10-20 21:09:02 -04:00
befs isystem: ship and use stdarg.h 2021-08-19 09:02:55 +09:00
bfs mm: require ->set_page_dirty to be explicitly wired up 2021-06-29 10:53:48 -07:00
btrfs btrfs: check WRITE_ERR when trying to read an extent buffer 2021-12-15 17:07:31 +01:00
cachefiles cachefiles: Change %p in format strings to something else 2021-08-27 13:34:02 +01:00
ceph ceph: fix handling of "meta" errors 2021-10-19 09:36:06 +02:00
cifs cifs: fix incorrect check for null pointer in header_assemble 2021-09-23 21:12:53 -05:00
coda coda: fix reference counting in coda_file_mmap error path 2021-04-23 14:42:39 -07:00
configfs configfs: fix a race in configfs_lookup() 2021-08-25 07:58:49 +02:00
cramfs
crypto fscrypt: align Base64 encoding with RFC 4648 base64url 2021-07-25 20:47:05 -07:00
debugfs debugfs: debugfs_create_file_size(): use IS_ERR to check for error 2021-09-21 09:09:06 +02:00
devpts
dlm fs: dlm: avoid comms shutdown delay in release_lockspace 2021-09-01 11:29:14 -05:00
ecryptfs mm: require ->set_page_dirty to be explicitly wired up 2021-06-29 10:53:48 -07:00
efivarfs efivars: convert to fileattr 2021-04-12 15:04:29 +02:00
efs
erofs erofs: clear compacted_2b if compacted_4b_initial > totalidx 2021-09-23 23:23:04 +08:00
exfat Description for this pull request: 2021-07-06 11:06:04 -07:00
exportfs
ext2 ext2: fix sleeping in atomic bugs on error 2021-09-22 13:05:23 +02:00
ext4 Fix a number of ext4 bugs in fast_commit, inline data, and delayed 2021-10-03 13:56:53 -07:00
f2fs f2fs-for-5.15-rc1 2021-09-04 10:48:47 -07:00
fat linux-kselftest-kunit-5.15-rc1 2021-09-02 12:32:12 -07:00
freevxfs
fscache fscache: Remove an unused static variable 2021-10-04 22:13:12 +01:00
fuse fuse: clean up error exits in fuse_fill_super() 2021-10-21 10:01:39 +02:00
gfs2 Merge branch 'work.gfs2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-09-09 12:45:26 -07:00
hfs hfs: add lock nesting notation to hfs_find_init 2021-07-15 10:13:49 -07:00
hfsplus hfsplus: report create_date to kstat.btime 2021-07-01 11:06:06 -07:00
hostfs hostfs: support splice_write 2021-08-26 22:28:02 +02:00
hpfs hpfs: use iomap_fiemap to implement ->fiemap 2021-07-27 11:00:36 +02:00
hugetlbfs hugetlbfs: fix mount mode command line processing 2021-07-23 17:43:28 -07:00
iomap iomap: standardize tracepoint formatting and storage 2021-08-26 09:18:53 -07:00
isofs isofs: joliet: Fix iocharset=utf8 mount option 2021-08-12 16:07:14 +02:00
jbd2 jbd2: add sparse annotations for add_transaction_credits() 2021-08-30 23:36:50 -04:00
jffs2 vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
jfs vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
kernfs kernfs: don't create a negative dentry if inactive node exists 2021-10-04 10:27:18 +02:00
ksmbd ksmbd: add buffer validation in session setup 2021-10-20 00:07:10 -05:00
lockd Critical bug fixes: 2021-09-22 09:21:02 -07:00
minix mm: require ->set_page_dirty to be explicitly wired up 2021-06-29 10:53:48 -07:00
netfs netfs: Fix READ/WRITE confusion when calling iov_iter_xarray() 2021-10-05 11:22:06 +01:00
nfs NFS Client Updates for Linux 5.15 2021-09-04 10:25:26 -07:00
nfs_common nfs: Fix kerneldoc warning shown up by W=1 2021-10-04 22:02:17 +01:00
nfsd Bug fixes for NFSD error handling paths 2021-10-07 14:11:40 -07:00
nilfs2 Merge branch 'akpm' (patches from Andrew) 2021-09-08 12:55:35 -07:00
nls
notify fsnotify: fix sb_connectors leak 2021-09-10 09:46:48 -07:00
ntfs Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-07-03 11:30:04 -07:00
ntfs3 Fixed xfstests generic/016 generic/021 generic/022 generic/041 generic/274 generic/423, 2021-10-15 09:58:11 -04:00
ocfs2 ocfs2: mount fails with buffer overflow in strlen 2021-10-18 20:22:03 -10:00
omfs mm: require ->set_page_dirty to be explicitly wired up 2021-06-29 10:53:48 -07:00
openpromfs openpromfs: don't do unlock_new_inode() until the new inode is set up 2021-03-12 22:15:22 -05:00
orangefs vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
overlayfs ovl: fix IOCB_DIRECT if underlying fs doesn't support direct IO 2021-09-28 09:16:12 +02:00
proc Merge branch 'akpm' (patches from Andrew) 2021-09-08 12:55:35 -07:00
pstore for-5.14/drivers-2021-06-29 2021-06-30 12:21:16 -07:00
qnx4 qnx4: work around gcc false positive warning bug 2021-09-21 08:36:48 -07:00
qnx6
quota quota: remove unnecessary oom message 2021-06-22 10:40:52 +02:00
ramfs fs: move ramfs_aops to libfs 2021-06-29 10:53:48 -07:00
reiserfs Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
romfs
smbfs_common cifs: remove pathname for file from SPDX header 2021-09-13 14:51:10 -05:00
squashfs squashfs: use bvec_virt 2021-08-16 10:50:32 -06:00
sysfs sysfs: Allow deferred execution of iomem_get_mapping() 2021-08-06 13:05:28 +02:00
sysv mm: require ->set_page_dirty to be explicitly wired up 2021-06-29 10:53:48 -07:00
tracefs tracing: Fix various typos in comments 2021-03-23 14:08:18 -04:00
ubifs ubifs: report correct st_size for encrypted symlinks 2021-07-25 20:01:07 -07:00
udf udf_get_extendedattr() had no boundary checks. 2021-08-23 13:35:19 +02:00
ufs isystem: ship and use stdarg.h 2021-08-19 09:02:55 +09:00
unicode .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
vboxsf vboxfs: fix broken legacy mount signature checking 2021-09-27 11:26:21 -07:00
verity fs-verity: fix signed integer overflow with i_size near S64_MAX 2021-09-22 10:56:34 -07:00
xfs libnvdimm for v5.15 2021-09-09 11:39:57 -07:00
zonefs \n 2021-08-30 10:24:50 -07:00
aio.c eventfd: Make signal recursion protection a task bit 2021-08-28 01:33:02 +02:00
anon_inodes.c
attr.c fs: Move notify_change permission checks into may_setattr 2021-08-13 00:41:05 -04:00
bad_inode.c vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
binfmt_aout.c binfmt: a.out: Fix bogus semicolon 2021-09-05 10:15:05 -07:00
binfmt_elf_fdpic.c binfmt: remove in-tree usage of MAP_DENYWRITE 2021-09-03 18:42:01 +02:00
binfmt_elf.c elf: don't use MAP_FIXED_NOREPLACE for elf interpreter mappings 2021-10-03 14:02:58 -07:00
binfmt_flat.c binfmt: remove in-tree usage of MAP_EXECUTABLE 2021-06-29 10:53:50 -07:00
binfmt_misc.c binfmt_misc: fix possible deadlock in bm_register_write 2021-03-13 11:27:30 -08:00
binfmt_script.c
buffer.c mm: fs: invalidate bh_lrus for only cold path 2021-09-24 16:13:35 -07:00
char_dev.c
compat_binfmt_elf.c
coredump.c coredump: fix memleak in dump_vma_snapshot() 2021-09-08 11:50:27 -07:00
d_path.c d_path: make 'prepend()' fill up the buffer exactly on overflow 2021-09-02 10:07:29 -07:00
dax.c New code for 5.15: 2021-08-31 11:13:35 -07:00
dcache.c useful constants: struct qstr for ".." 2021-04-15 22:36:45 -04:00
direct-io.c fs: direct-io: fix missing sdio->boundary 2021-04-09 14:54:23 -07:00
drop_caches.c fs: drop_caches: fix skipping over shadow cache inodes 2021-09-03 09:58:10 -07:00
eventfd.c eventfd: Export eventfd_wake_count to modules 2021-09-06 07:20:56 -04:00
eventpoll.c ARM development updates for 5.15: 2021-09-09 13:25:49 -07:00
exec.c Merge tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux 2021-09-04 11:35:47 -07:00
fcntl.c Merge branch 'akpm' (patches from Andrew) 2021-09-03 10:08:28 -07:00
fhandle.c switch file_open_root() to struct path 2021-04-07 13:56:43 -04:00
file_table.c
file.c virtio,vdpa,vhost: features, fixes 2021-09-11 14:48:42 -07:00
filesystems.c fs: simplify get_filesystem_list / get_all_fs_names 2021-08-23 01:25:40 -04:00
fs_context.c memcg: charge fs_context and legacy_fs_context 2021-09-03 09:58:12 -07:00
fs_parser.c namei: Standardize callers of filename_lookup() 2021-09-07 16:07:47 -04:00
fs_pin.c
fs_struct.c
fs_types.c
fs-writeback.c Merge branch 'akpm' (patches from Andrew) 2021-09-03 10:08:28 -07:00
fsopen.c
init.c
inode.c fs: export an inode_update_time helper 2021-10-26 19:08:08 +02:00
internal.h block: move fs/block_dev.c to block/bdev.c 2021-09-07 08:39:40 -06:00
io_uring.c io_uring: apply worker limits to previous users 2021-10-21 11:19:38 -06:00
io-wq.c io-wq: max_worker fixes 2021-10-19 17:09:34 -06:00
io-wq.h io-wq: provide a way to limit max number of workers 2021-08-29 07:55:55 -06:00
ioctl.c New code for 5.15: 2021-08-31 11:06:32 -07:00
Kconfig 4 cifs/smb3 fixes, one for DFS reconnect, and one to begin creating common headers for server and client and the other two to rename the cifs_common directory to smbfs_common to be more consistent ie change use of the name cifs to smb which is more accurate 2021-09-12 10:10:21 -07:00
Kconfig.binfmt binfmt: remove support for em86 (alpha only) 2021-07-25 22:33:03 -07:00
kernel_read_file.c vfs: check fd has read access in kernel_read_file_from_fd() 2021-10-18 20:22:03 -10:00
libfs.c fs: remove noop_set_page_dirty() 2021-06-29 10:53:48 -07:00
locks.c Revert "memcg: enable accounting for file lock caches" 2021-09-07 11:21:48 -07:00
Makefile 4 cifs/smb3 fixes, one for DFS reconnect, and one to begin creating common headers for server and client and the other two to rename the cifs_common directory to smbfs_common to be more consistent ie change use of the name cifs to smb which is more accurate 2021-09-12 10:10:21 -07:00
mbcache.c
mount.h
mpage.c block: rename BIO_MAX_PAGES to BIO_MAX_VECS 2021-03-11 07:47:48 -07:00
namei.c putname(): IS_ERR_OR_NULL() is wrong here 2021-09-07 16:14:05 -04:00
namespace.c Merge branch 'akpm' (patches from Andrew) 2021-09-03 10:08:28 -07:00
no-block.c
nsfs.c
open.c fs: remove mandatory file locking support 2021-08-23 06:15:36 -04:00
pipe.c Revert "mm/gup: remove try_get_page(), call try_get_compound_head() directly" 2021-09-07 11:03:45 -07:00
pnode.c
pnode.h mount: fix mounting of detached mounts onto targets that reside on shared mounts 2021-03-08 15:18:43 +01:00
posix_acl.c ovl: enable RCU'd ->get_acl() 2021-08-18 22:08:24 +02:00
proc_namespace.c
read_write.c fs: clean up after mandatory file locking support removal 2021-08-24 07:52:45 -04:00
readdir.c readdir: make sure to verify directory entry for legacy interfaces too 2021-04-17 11:39:49 -07:00
remap_range.c fs: remove mandatory file locking support 2021-08-23 06:15:36 -04:00
select.c Revert "memcg: enable accounting for pollfd and select bits arrays" 2021-09-07 11:26:23 -07:00
seq_file.c seq_file: disallow extremely large seq buffer allocations 2021-07-19 17:18:48 -07:00
signalfd.c signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency 2021-07-23 13:16:43 -05:00
splice.c
stack.c
stat.c fs: add generic helper for filling statx attribute flags 2021-08-17 11:47:43 +02:00
statfs.c
super.c block: remove the bd_bdi in struct block_device 2021-08-09 11:53:26 -06:00
sync.c
timerfd.c timerfd: Provide timerfd_resume() 2021-08-10 17:57:22 +02:00
userfaultfd.c userfaultfd: fix a race between writeprotect and exit_mmap() 2021-10-18 20:22:02 -10:00
utimes.c
xattr.c xattr: fix kernel-doc for mnt_userns and vfs xattr helpers 2021-03-23 11:20:26 +01:00