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TencentOS-kernel/fs/btrfs
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Boris Burkov 6bceebef3b btrfs: detect nocow for swap after snapshot delete 
commit a84d5d429f9eb56f81b388609841ed993f0ddfca upstream.

can_nocow_extent and btrfs_cross_ref_exist both rely on a heuristic for
detecting a must cow condition which is not exactly accurate, but saves
unnecessary tree traversal. The incorrect assumption is that if the
extent was created in a generation smaller than the last snapshot
generation, it must be referenced by that snapshot. That is true, except
the snapshot could have since been deleted, without affecting the last
snapshot generation.

The original patch claimed a performance win from this check, but it
also leads to a bug where you are unable to use a swapfile if you ever
snapshotted the subvolume it's in. Make the check slower and more strict
for the swapon case, without modifying the general cow checks as a
compromise. Turning swap on does not seem to be a particularly
performance sensitive operation, so incurring a possibly unnecessary
btrfs_search_slot seems worthwhile for the added usability.

Note: Until the snapshot is competely cleaned after deletion,
check_committed_refs will still cause the logic to think that cow is
necessary, so the user must until 'btrfs subvolu sync' finished before
activating the swapfile swapon.

CC: stable@vger.kernel.org # 5.4+
Suggested-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2021-03-16 16:35:10 +08:00
..
tests Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
Kconfig Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
Makefile Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
acl.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
async-thread.c Btrfs: fix crash during unmount due to race with delayed inode workers 2021-03-16 16:26:08 +08:00
async-thread.h Btrfs: fix crash during unmount due to race with delayed inode workers 2021-03-16 16:26:08 +08:00
backref.c btrfs: fix double free on ulist after backref resolution failure 2021-03-16 16:32:22 +08:00
backref.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
block-group.c btrfs: add wrapper for transaction abort predicate 2021-03-16 16:34:27 +08:00
block-group.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
block-rsv.c btrfs: force chunk allocation if our global rsv is larger than metadata 2021-03-16 16:29:39 +08:00
block-rsv.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
btrfs_inode.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
check-integrity.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
check-integrity.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
compression.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
compression.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
ctree.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
ctree.h btrfs: detect nocow for swap after snapshot delete 2021-03-16 16:35:10 +08:00
delalloc-space.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
delalloc-space.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
delayed-inode.c btrfs: add wrapper for transaction abort predicate 2021-03-16 16:34:27 +08:00
delayed-inode.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
delayed-ref.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
delayed-ref.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
dev-replace.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
dev-replace.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
dir-item.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
disk-io.c btrfs: fix space cache memory leak after transaction abort 2021-03-16 16:35:10 +08:00
disk-io.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
export.c btrfs: export helpers for subvolume name/id resolution 2021-03-16 16:34:27 +08:00
export.h btrfs: export helpers for subvolume name/id resolution 2021-03-16 16:34:27 +08:00
extent-tree.c btrfs: detect nocow for swap after snapshot delete 2021-03-16 16:35:10 +08:00
extent_io.c btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases 2021-03-16 16:34:27 +08:00
extent_io.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
extent_map.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
extent_map.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
file-item.c btrfs: do not ignore error from btrfs_next_leaf() when inserting checksums 2021-03-16 16:29:21 +08:00
file.c btrfs: detect nocow for swap after snapshot delete 2021-03-16 16:35:10 +08:00
free-space-cache.c btrfs: fix space cache memory leak after transaction abort 2021-03-16 16:35:10 +08:00
free-space-cache.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
free-space-tree.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
free-space-tree.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
inode-item.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
inode-map.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
inode-map.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
inode.c btrfs: detect nocow for swap after snapshot delete 2021-03-16 16:35:10 +08:00
ioctl.c btrfs: add missing check for nocow and compression inode flags 2021-03-16 16:34:01 +08:00
locking.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
locking.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
lzo.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
misc.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
ordered-data.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
ordered-data.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
orphan.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
print-tree.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
print-tree.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
props.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
props.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
qgroup.c btrfs: make btrfs_qgroup_check_reserved_leak take btrfs_inode 2021-03-16 16:34:52 +08:00
qgroup.h btrfs: make btrfs_qgroup_check_reserved_leak take btrfs_inode 2021-03-16 16:34:52 +08:00
raid56.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
raid56.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
rcu-string.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
reada.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
ref-verify.c btrfs: ref-verify: fix memory leak in add_block_entry 2021-03-16 16:33:59 +08:00
ref-verify.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
relocation.c btrfs: relocation: review the call sites which can be interrupted by signal 2021-03-16 16:34:00 +08:00
root-tree.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
scrub.c btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases 2021-03-16 16:34:27 +08:00
send.c btrfs: send: emit file capabilities after chown 2021-03-16 16:29:39 +08:00
send.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
space-info.c btrfs: fix lockdep splat from btrfs_dump_space_info 2021-03-16 16:33:22 +08:00
space-info.h btrfs: improve global reserve stealing logic 2021-03-16 16:29:34 +08:00
struct-funcs.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
super.c btrfs: reset compression level for lzo on remount 2021-03-16 16:35:09 +08:00
sysfs.c btrfs: sysfs: use NOFS for device creation 2021-03-16 16:34:01 +08:00
sysfs.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
transaction.c btrfs: add wrapper for transaction abort predicate 2021-03-16 16:34:27 +08:00
transaction.h btrfs: add wrapper for transaction abort predicate 2021-03-16 16:34:27 +08:00
tree-checker.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
tree-checker.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
tree-defrag.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
tree-log.c btrfs: check the right error variable in btrfs_del_dir_entries_in_log 2021-03-16 16:35:09 +08:00
tree-log.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
ulist.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
ulist.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
uuid-tree.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
volumes.c btrfs: relocation: review the call sites which can be interrupted by signal 2021-03-16 16:34:00 +08:00
volumes.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
xattr.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
xattr.h Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
zlib.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
zstd.c Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00