linux/fs
Josef Bacik 39dba8739c btrfs: do not resolve backrefs for roots that are being deleted
Zygo reported a deadlock where a task was stuck in the inode logical
resolve code.  The deadlock looks like this

  Task 1
  btrfs_ioctl_logical_to_ino
  ->iterate_inodes_from_logical
   ->iterate_extent_inodes
    ->path->search_commit_root isn't set, so a transaction is started
      ->resolve_indirect_ref for a root that's being deleted
	->search for our key, attempt to lock a node, DEADLOCK

  Task 2
  btrfs_drop_snapshot
  ->walk down to a leaf, lock it, walk up, lock node
   ->end transaction
    ->start transaction
      -> wait_cur_trans

  Task 3
  btrfs_commit_transaction
  ->wait_event(cur_trans->write_wait, num_writers == 1) DEADLOCK

We are holding a transaction open in btrfs_ioctl_logical_to_ino while we
try to resolve our references.  btrfs_drop_snapshot() holds onto its
locks while it stops and starts transaction handles, because it assumes
nobody is going to touch the root now.  Commit just does what commit
does, waiting for the writers to finish, blocking any new trans handles
from starting.

Fix this by making the backref code not try to resolve backrefs of roots
that are currently being deleted.  This will keep us from walking into a
snapshot that's currently being deleted.

This problem was harder to hit before because we rarely broke out of the
snapshot delete halfway through, but with my delayed ref throttling code
it happened much more often.  However we've always been able to do this,
so it's not a new problem.

Fixes: 8da6d5815c ("Btrfs: added btrfs_find_all_roots()")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-03-23 17:03:51 +01:00
..
9p 9p pull request for inclusion in 5.4 2019-09-27 15:10:34 -07:00
adfs fs/adfs: bigdir: Fix an error code in adfs_fplus_read() 2020-01-25 11:31:59 -05:00
affs affs: fix a memory leak in affs_remount 2019-11-18 14:26:43 +01:00
afs afs: Use kfree_rcu() instead of casting kfree() to rcu_callback_t 2020-03-13 10:47:33 -07:00
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: do not resolve backrefs for roots that are being deleted 2020-03-23 17:03:51 +01:00
cachefiles cachefiles: drop direct usage of ->bmap method. 2020-02-03 08:05:56 -05:00
ceph ceph: noacl mount option is effectively ignored 2020-02-11 17:04:40 +01:00
cifs three small smb3 fixes, 2 for stable 2020-03-19 10:19:11 -07:00
coda y2038: add inode timestamp clamping 2019-09-19 09:42:37 -07:00
configfs utimes: Clamp the timestamps in notify_change() 2019-12-08 19:10:50 -05:00
cramfs cramfs: switch to use of errofc() et.al. 2020-02-07 14:48:41 -05:00
crypto fscrypt: don't evict dirty inodes after removing key 2020-03-07 18:43:07 -08:00
debugfs debugfs: remove return value of debugfs_create_regset32() 2020-02-10 13:00:06 -08:00
devpts devpts_pty_kill(): don't bother with d_delete() 2019-09-03 09:30:56 -04:00
dlm dlm: use SO_SNDTIMEO_NEW instead of SO_SNDTIMEO_OLD 2019-12-18 18:07:31 +01:00
ecryptfs eCryptfs fixes for 5.6-rc3 2020-02-17 21:08:37 -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 erofs: clean up z_erofs_submit_queue() 2020-01-21 16:46:23 +08:00
exportfs race in exportfs_decode_fh() 2019-11-11 09:21:59 -05:00
ext2 dax fixes 5.6-rc1 2020-02-11 16:52:08 -08:00
ext4 ext4: potential crash on allocation error in ext4_alloc_flex_bg_array() 2020-02-29 17:48:08 -05:00
f2fs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:04:49 -08:00
fat fat: fix uninit-memory access for partial initialized inode 2020-03-06 07:06:09 -06:00
freevxfs fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
fscache proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
fuse fuse: fix stack use after return 2020-02-13 09:16:07 +01:00
gfs2 gfs2_atomic_open(): fix O_EXCL|O_CREAT handling on cold dcache 2020-03-12 18:21:24 -04:00
hfs hfs/hfsplus: use 64-bit inode timestamps 2019-12-18 18:07:32 +01:00
hfsplus hfs/hfsplus: use 64-bit inode timestamps 2019-12-18 18:07:32 +01:00
hostfs hostfs: pass 64-bit timestamps to/from user space 2019-12-18 18:07:32 +01:00
hpfs fs: compat_ioctl: move FITRIM emulation into file systems 2019-10-23 17:23:46 +02:00
hugetlbfs hugetlbfs: switch to use of invalfc() 2020-02-07 14:48:42 -05:00
iomap fs: Fix page_mkwrite off-by-one errors 2020-01-06 08:58:23 -08:00
isofs y2038: add inode timestamp clamping 2019-09-19 09:42:37 -07:00
jbd2 jbd2: fix data races at struct journal_head 2020-02-29 13:40:02 -05:00
jffs2 fs_parse: fold fs_parameter_desc/fs_parameter_spec 2020-02-07 14:48:37 -05:00
jfs Trivial cleanup for jfs 2020-02-05 05:28:20 +00:00
kernfs Merge branch 'imm.timestamp' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-05 05:02:42 +00:00
lockd proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
minix fs: Fill in max and min timestamps in superblock 2019-08-30 07:27:17 -07:00
nfs nfs: add minor version to nfs_server_key for fscache 2020-02-25 13:53:24 -05:00
nfs_common
nfsd Highlights: 2020-02-07 17:50:21 -08:00
nilfs2 fs: compat_ioctl: move FITRIM emulation into file systems 2019-10-23 17:23:46 +02:00
nls
notify fs: call fsnotify_sb_delete after evict_inodes 2019-12-18 00:03:01 -05:00
ntfs utimes: Clamp the timestamps in notify_change() 2019-12-08 19:10:50 -05:00
ocfs2 treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
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 help_next should increase position index 2020-02-04 15:22:04 -05:00
overlayfs ovl: fix lockdep warning for async write 2020-03-13 15:53:06 +01:00
proc Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
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 \n 2020-01-30 15:37:41 -08:00
ramfs fs_parse: fold fs_parameter_desc/fs_parameter_spec 2020-02-07 14:48:37 -05:00
reiserfs Merge branch 'akpm' (patches from Andrew) 2020-01-31 12:16:36 -08:00
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 treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
sysv fs: sysv: Initialize filesystem timestamp ranges 2019-08-30 07:27:18 -07:00
tracefs simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems 2019-12-10 22:29:58 -05:00
ubifs Merge branch 'imm.timestamp' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-05 05:02:42 +00:00
udf udf: Clarify meaning of f_files in udf_statfs 2020-01-20 13:59:41 +01:00
ufs y2038: add inode timestamp clamping 2019-09-19 09:42:37 -07:00
unicode kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
vboxsf fs: Add VirtualBox guest shared folder (vboxsf) support 2020-02-08 17:34:58 -05:00
verity fs-verity: use u64_to_user_ptr() 2020-01-14 13:28:28 -08:00
xfs dax fixes 5.6-rc1 2020-02-11 16:52:08 -08:00
zonefs zonefs: select FS_IOMAP 2020-02-26 16:58:15 +09:00
aio.c aio: prevent potential eventfd recursion on poll 2020-02-03 17:27:47 -07:00
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 utimes: Clamp the timestamps in notify_change() 2019-12-08 19:10:50 -05:00
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c y2038: elfcore: Use __kernel_old_timeval for process times 2019-11-15 14:38:29 +01:00
binfmt_elf.c fs/binfmt_elf.c: coredump: allow process with empty address space to coredump 2020-01-31 10:30:41 -08:00
binfmt_em86.c
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
block_dev.c block: don't send uevent for empty disk when not invalidating 2019-12-02 18:49:30 -07:00
buffer.c smp: Remove allocation mask from on_each_cpu_cond.*() 2020-01-24 20:40:09 +01:00
char_dev.c chardev: Avoid potential use-after-free in 'chrdev_open()' 2020-01-06 20:10:26 +01:00
compat_binfmt_elf.c y2038: elfcore: Use __kernel_old_timeval for process times 2019-11-15 14:38:29 +01:00
compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
coredump.c pipe: use exclusive waits when reading or writing 2020-02-08 11:39:19 -08:00
d_path.c [PATCH] fix d_absolute_path() interplay with fsmount() 2019-08-30 19:31:09 -04:00
dax.c dax: pass NOWAIT flag to iomap_apply 2020-02-05 20:34:32 -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
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 eventfd: track eventfd_signal() recursion depth 2020-02-03 17:27:38 -07:00
eventpoll.c epoll: fix possible lost wakeup on epoll_ctl() path 2020-03-21 18:56:06 -07:00
exec.c Merge branch 'akpm' (patches from Andrew) 2020-01-31 12:16:36 -08:00
fcntl.c fcntl: Distribute switch variables for initialization 2020-03-03 10:55:06 -05:00
fhandle.c fs/handle.c - fix up kerneldoc 2019-08-07 21:51:47 -04:00
file_table.c vfs: Export flush_delayed_fput for use by knfsd. 2019-08-19 11:00:39 -04:00
file.c io_uring: make sure openat/openat2 honor rlimit nofile 2020-03-20 08:47:27 -06:00
filesystems.c fs_parser: remove fs_parameter_description name field 2020-02-07 14:48:36 -05:00
fs_context.c add prefix to fs_context->log 2020-02-07 14:48:35 -05:00
fs_parser.c turn fs_param_is_... into functions 2020-02-07 14:48:38 -05:00
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
fs_types.c
fs-writeback.c memcg: fix a crash in wb_workfn when a device disappears 2020-01-31 10:30:36 -08:00
fsopen.c add prefix to fs_context->log 2020-02-07 14:48:35 -05:00
inode.c futex: Fix inode life-time issue 2020-03-06 11:06:15 +01:00
internal.h for-5.6/io_uring-vfs-2020-01-29 2020-01-29 18:53:37 -08:00
io_uring.c io_uring: make sure accept honor rlimit nofile 2020-03-20 08:48:36 -06:00
io-wq.c io-wq: remove io_wq_flush and IO_WQ_WORK_INTERNAL 2020-03-02 14:03:24 -07:00
io-wq.h io-wq: remove io_wq_flush and IO_WQ_WORK_INTERNAL 2020-03-02 14:03:24 -07:00
ioctl.c compat-ioctl fix for v5.6 2020-02-08 13:44:41 -08:00
Kconfig fs: New zonefs file system 2020-02-09 15:51:46 -08:00
Kconfig.binfmt binfmt_flat: make support for old format binaries optional 2019-06-24 09:16:47 +10:00
libfs.c simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems 2019-12-10 22:29:58 -05:00
locks.c locks: reinstate locks_delete_block optimization 2020-03-18 13:03:38 -07:00
Makefile fs: New zonefs file system 2020-02-09 15:51:46 -08:00
mbcache.c
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 vfs: fix do_last() regression 2020-02-01 10:36:49 -08:00
namespace.c saner copy_mount_options() 2020-02-03 21:23:33 -05:00
no-block.c
nsfs.c Merge branch 'work.openat2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-01-29 11:20:24 -08:00
open.c cifs_atomic_open(): fix double-put on late allocation failure 2020-03-12 18:25:20 -04:00
pipe.c pipe: make sure to wake up everybody when the last reader/writer closes 2020-02-18 14:34:36 -08:00
pnode.c fs/namespace: fix unprivileged mount propagation 2019-06-17 17:36:09 -04:00
pnode.h
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 overlayfs update for 5.6 2020-02-04 11:45:21 +00:00
readdir.c readdir: make user_access_begin() use the real access range 2020-01-23 10:15:28 -08:00
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
splice.c pipe: use exclusive waits when reading or writing 2020-02-08 11:39:19 -08:00
stack.c sched/rt, fs: Use CONFIG_PREEMPTION 2019-12-08 14:37:36 +01:00
stat.c fs: make two stat prep helpers available 2020-01-20 17:03:54 -07:00
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
timerfd.c timerfd: Make timerfd_settime() time namespace aware 2020-01-14 12:20:53 +01:00
userfaultfd.c Merge branch 'akpm' (patches from Andrew) 2019-12-01 20:36:41 -08:00
utimes.c utimes: Clamp the timestamps in notify_change() 2019-12-08 19:10:50 -05:00
xattr.c