Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-18 01:51:53 +00:00
Code Issues Packages Projects Releases Wiki Activity
b7774425e0
linux/fs
History
Josef Bacik b7774425e0 btrfs: remove bogus BUG_ON in alloc_reserved_tree_block 
The fix 361048f586 ("Btrfs: fix full backref problem when inserting
shared block reference") added a delayed ref flushing at subvolume
creation time in order to avoid hitting this particular BUG_ON().

Before this fix, we were tripping the BUG_ON() by

1. Modify snapshot A, which creates blocks with a normal reference for
   snapshot A, as A is the owner of these blocks.  We now have delayed
   refs for these blocks.
2. Create a snapshot of A named B, which pushes references for the
   children blocks of the root node for the new root B, thus creating
   more delayed refs for newly allocated blocks.
3. A is modified, and because the metadata blocks can now be shared, it
   must push FULL_BACKREF references to the children of any block that A
   COWs down it's path to its target key.
4. Delayed refs are run.  Because these are newly allocated blocks, we
   have ->must_insert_reserved reserved set on the delayed ref head, we
   call into alloc_reserved_tree_block() to add the extent item, and
   then add our ref.  At the time of this fix, we were ordering
   FULL_BACKREF delayed ref operations first, so we'd go to add this
   reference and then BUG_ON() because we didn't have the FULL_BACKREF
   flag set.

The patch fixed this problem by making sure we ran the delayed refs
before we had the chance to modify A.  This meant that any *new* blocks
would have had their extent items created _before_ we would ever
actually COW down and generate FULL_BACKREF entries.  Thus the problem
went away.

However this BUG_ON() is actually completely bogus.  The existence of a
full backref doesn't necessarily mean that FULL_BACKREF must be set on
that block, it must only be set on the actual parent itself.  Consider
the example provided above.  If we COW down one path from A, any nodes
are going to have a FULL_BACKREF ref pushed down to _all_ of their
children, but not all of the children are going to have FULL_BACKREF
set.  It is completely valid to have an extent item with normal and full
backrefs without FULL_BACKREF actually set on the block itself.

As a final note, I have been testing with the patch (applied after this
one)

  btrfs: stop running all delayed refs during snapshot

which removed this flushing.  My test was a torture test which did a lot
of operations while snapshotting and deleting snapshots as well as
relocation, and I never tripped this BUG_ON().  This is actually because
at the time of 361048f586, we ordered SHARED keys _before_ normal
references, and thus they would get run first.  However currently they
are ordered _after_ normal references, so we'd do the initial creation
without having a shared reference, and thus not hit this BUG_ON(), which
explains why I didn't start hitting this problem during my testing with
my other patch applied.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-08 22:58:57 +01:00
..
9p 9p for 5.11-rc1 2020-12-21 10:28:02 -08:00
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 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
afs rxrpc: Fix deadlock around release of dst cached on udp tunnel 2021-01-29 21:38:11 -08:00
autofs file: Replace ksys_close with close_fd 2020-12-10 12:42:59 -06:00
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. 2020-12-15 22:46:18 -08:00
btrfs btrfs: remove bogus BUG_ON in alloc_reserved_tree_block 2021-02-08 22:58:57 +01:00
cachefiles cachefiles: Drop superfluous readpages aops NULL check 2021-01-20 11:33:51 -08:00
ceph libceph, ceph: disambiguate ceph_connection_operations handlers 2021-01-04 17:31:32 +01:00
cifs cifs: report error instead of invalid when revalidating a dentry fails 2021-02-05 13:17:48 -06:00
coda docs: filesystems: convert coda.txt to ReST 2020-05-05 09:22:21 -06:00
configfs configfs: fix kernel-doc markup issue 2020-11-14 10:22:45 +01:00
cramfs [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
crypto f2fs-for-5.11-rc1 2020-12-17 11:18:00 -08:00
debugfs debugfs: remove return value of debugfs_create_devm_seqfile() 2020-10-30 08:37:39 +01:00
devpts
dlm fs: dlm: check on existing node address 2020-11-10 12:14:20 -06:00
ecryptfs ecryptfs: fix uid translation for setxattr on security.capability 2021-01-26 01:47:14 +00:00
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: avoid using generic_block_bmap 2020-12-10 11:07:40 +08:00
exfat exfat: Avoid allocating upcase table using kcalloc() 2020-12-22 12:31:17 +09:00
exportfs exportfs: Add a function to return the raw output from fh_to_dentry() 2020-12-09 09:39:38 -05:00
ext2 ext2: Fix fall-through warnings for Clang 2020-11-23 10:36:53 +01:00
ext4 A number of bug fixes for ext4: 2021-01-15 14:54:24 -08:00
f2fs f2fs-for-5.11-rc1 2020-12-17 11:18:00 -08:00
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 2020-12-10 15:33:14 +01:00
gfs2 gfs2: in signal_our_withdraw wait for unfreeze of _this_ fs only 2020-12-03 17:04:41 +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 fix hostfs_open() use of ->f_path.dentry 2020-12-21 21:42:29 -05:00
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 2021-02-05 11:03:47 -08:00
iomap mm: memcontrol: Use helpers to read page's memcg data 2020-12-02 18:28:05 -08:00
isofs fs: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
jbd2 jbd2: add a helper to find out number of fast commit blocks 2020-12-17 13:30:45 -05:00
jffs2 jffs2: Fix NULL pointer dereference in rp_size fs option parsing 2020-12-13 21:57:21 +01:00
jfs jfs: Fix array index bounds check in dbAdjTree 2020-11-13 16:03:07 -06:00
kernfs kernfs: wire up ->splice_read and ->splice_write 2021-01-21 18:30:28 +01:00
lockd fs/lockd: convert comma to semicolon 2020-12-16 07:57:37 -05:00
minix [PATCH] reduce boilerplate in fsid handling 2020-09-18 16:45:50 -04:00
nfs pNFS/NFSv4: Improve rejection of out-of-order layouts 2021-01-24 20:52:31 -05:00
nfs_common nfs_common: need lock during iterate through the list 2020-12-09 09:38:34 -05:00
nfsd nfsd4: readdirplus shouldn't return parent of export 2021-01-12 08:54:14 -05:00
nilfs2 fs/nilfs2: remove some unused macros to tame gcc 2020-12-15 22:46:17 -08:00
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 2020-12-28 11:58:59 +01:00
ntfs fs/ntfs: remove unused variable attr_len 2020-12-15 12:13:37 -08:00
ocfs2 ocfs2: ratelimit the 'max lookup times reached' notice 2020-12-15 12:13:37 -08:00
omfs fs: omfs: use kmemdup() rather than kmalloc+memcpy 2020-09-22 23:39:45 -04:00
openpromfs
orangefs orangefs: add splice file operations 2020-12-16 16:14:08 -05:00
overlayfs ovl: implement volatile-specific fsync error behaviour 2021-01-28 10:22:48 +01:00
proc proc_sysctl: fix oops caused by incorrect command parameters 2021-01-24 10:34:53 -08:00
pstore Tracing updates for 5.11 2020-12-17 13:22:17 -08:00
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 \n 2020-12-17 11:00:37 -08:00
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 2020-11-26 16:57:28 +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 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
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 This pull request contains changes for JFFS2, UBI and UBIFS: 2020-12-17 17:46:34 -08:00
udf udf: fix the problem that the disc content is not displayed 2021-01-18 12:06:33 +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 Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-12-14 12:18:19 -08:00
xfs New code for 5.11: 2020-12-18 12:50:18 -08:00
zonefs zonefs: select CONFIG_CRC32 2021-01-04 09:06:42 +09:00
aio.c Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -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 exec: Rename flush_old_exec begin_new_exec 2020-05-07 16:55:47 -05:00
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 Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-12-15 19:29:43 -08:00
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 2021-01-27 09:14:12 -07:00
buffer.c for-5.11/block-2020-12-14 2020-12-16 12:57:51 -08:00
char_dev.c vfs: allow unprivileged whiteout creation 2020-05-14 16:44:23 +02:00
compat_binfmt_elf.c elf: Expose ELF header on arch_setup_additional_pages() 2020-10-26 13:46:47 +01:00
coredump.c Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-12-15 19:29:43 -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: simplify follow_pte{,pmd} 2020-12-15 22:46:19 -08:00
dcache.c fs: Kill DCACHE_DONTCACHE dentry even if DCACHE_REFERENCED is set 2020-12-10 17:33:17 -05:00
dcookies.c
direct-io.c \n 2020-10-15 15:03:10 -07:00
drop_caches.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
eventfd.c eventfd: Export eventfd_ctx_do_read() 2020-11-15 09:49:10 -05:00
eventpoll.c epoll: add syscall epoll_pwait2 2020-12-19 11:18:38 -08:00
exec.c Merge branch 'parisc-5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2020-12-16 12:10:40 -08:00
fcntl.c fcntl: Fix potential deadlock in send_sig{io, urg}() 2020-11-05 07:44:15 -05:00
fhandle.c
file_table.c epoll: take epitem list out of struct file 2020-10-25 20:02:08 -04:00
file.c kernel/io_uring: cancel io_uring before task works 2020-12-30 19:36:54 -07:00
filesystems.c fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once() 2020-04-10 15:36:22 -07:00
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() 2021-01-13 17:26:21 +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 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-12-25 10:54:29 -08:00
internal.h for-5.11/block-2020-12-14 2020-12-16 12:57:51 -08:00
io_uring.c io_uring: drop mm/files between task_work_submit 2021-02-04 12:42:58 -07:00
io-wq.c io-wq: kill now unused io_wq_cancel_all() 2020-12-20 10:47:42 -07:00
io-wq.h io-wq: kill now unused io_wq_cancel_all() 2020-12-20 10:47:42 -07:00
ioctl.c fs: remove ksys_ioctl 2020-07-31 08:16:01 +02:00
Kconfig tmpfs: support 64-bit inums per-sb 2020-08-07 11:33:24 -07:00
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 f2fs-for-5.11-rc1 2020-12-17 11:18:00 -08:00
locks.c Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-12-15 19:29:43 -08:00
Makefile Refactored code for 5.10: 2020-10-23 11:33:41 -07:00
mbcache.c
mount.h mnt: Use generic ns_common::count 2020-08-19 14:14:19 +02:00
mpage.c fs: convert mpage_readpages to mpage_readahead 2020-06-02 10:59:07 -07:00
namei.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-12-25 10:54:29 -08:00
namespace.c umount(2): move the flag validity checks first 2021-01-04 15:31:58 -05:00
no-block.c
nsfs.c nsproxy: attach to namespaces via pidfds 2020-05-13 11:41:22 +02:00
open.c Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-12-15 19:29:43 -08:00
pipe.c fs/pipe: allow sendfile() to pipe again 2021-01-25 12:32:26 -08:00
pnode.c propagate_one(): mnt_set_mountpoint() needs mount_lock 2020-04-27 10:37:14 -04:00
pnode.h fs/namespace.c: WARN if mnt_count has become negative 2020-12-10 17:33:17 -05:00
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 2020-12-27 12:00:36 -08:00
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: verify source area in vfs_dedupe_file_range_one() 2020-12-14 15:26:13 +01:00
select.c poll: fix performance regression due to out-of-line __put_user() 2021-01-08 11:06:29 -08:00
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 block: remove i_bdev 2020-12-01 14:53:39 -07:00
super.c block: remove i_bdev 2020-12-01 14:53:39 -07:00
sync.c overlayfs update for 5.8 2020-06-09 15:40:50 -07:00
timerfd.c
userfaultfd.c userfaultfd: add user-mode only option to unprivileged_userfaultfd sysctl knob 2020-12-15 12:13:46 -08:00
utimes.c fs: expose utimes_common 2020-07-31 08:16:01 +02:00
xattr.c vfs: move cap_convert_nscap() call into vfs_setxattr() 2020-12-14 15:26:13 +01:00