WSL2-Linux-Kernel/fs/btrfs
Nikolay Borisov 1a89025056 btrfs: Fix memory barriers usage with device stats counters
commit 9deae96892 upstream.

Commit addc3fa74e ("Btrfs: Fix the problem that the dirty flag of dev
stats is cleared") reworked the way device stats changes are tracked. A
new atomic dev_stats_ccnt counter was introduced which is incremented
every time any of the device stats counters are changed. This serves as
a flag whether there are any pending stats changes. However, this patch
only partially implemented the correct memory barriers necessary:

- It only ordered the stores to the counters but not the reads e.g.
  btrfs_run_dev_stats
- It completely omitted any comments documenting the intended design and
  how the memory barriers pair with each-other

This patch provides the necessary comments as well as adds a missing
smp_rmb in btrfs_run_dev_stats. Furthermore since dev_stats_cnt is only
a snapshot at best there was no point in reading the counter twice -
once in btrfs_dev_stats_dirty and then again when assigning stats_cnt.
Just collapse both reads into 1.

Fixes: addc3fa74e ("Btrfs: Fix the problem that the dirty flag of dev stats is cleared")
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-21 12:06:44 +01:00
..
tests btrfs: tests: Fix a memory leak in error handling path in 'run_test()' 2017-12-20 10:10:30 +01:00
Kconfig btrfs: Add zstd support 2017-08-15 09:02:09 -07:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
acl.c btrfs: preserve i_mode if __btrfs_set_acl() fails 2017-08-21 17:47:42 +02:00
async-thread.c btrfs: constify tracepoint arguments 2017-08-16 14:19:53 +02:00
async-thread.h btrfs: constify tracepoint arguments 2017-08-16 14:19:53 +02:00
backref.c btrfs: remove spurious WARN_ON(ref->count < 0) in find_parent_nodes 2018-03-21 12:06:44 +01:00
backref.h btrfs: backref, add tracepoints for prelim_ref insertion and merging 2017-08-16 16:12:01 +02:00
btrfs_inode.h btrfs: separate defrag and property compression 2017-08-16 16:12:05 +02:00
check-integrity.c Merge branch 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux 2017-09-09 13:27:51 -07:00
check-integrity.h btrfs: take an fs_info directly when the root is not used otherwise 2016-12-06 16:06:59 +01:00
compression.c Merge branch 'for-4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux 2017-09-29 12:57:35 -07:00
compression.h Merge branch 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2017-09-14 17:30:49 -07:00
ctree.c btrfs: handle errors while updating refcounts in update_ref_for_cow 2017-12-14 09:52:54 +01:00
ctree.h Merge branch 'for-4.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux 2017-10-06 09:03:08 -07:00
dedupe.h btrfs: expand cow_file_range() to support in-band dedup and subpage-blocksize 2016-07-26 13:52:25 +02:00
delayed-inode.c Btrfs: fix stale entries in readdir 2018-01-31 14:03:42 +01:00
delayed-inode.h btrfs: convert btrfs_delayed_item.refs from atomic_t to refcount_t 2017-04-18 14:07:23 +02:00
delayed-ref.c Btrfs: return old and new total ref mods when adding delayed refs 2017-06-29 20:17:01 +02:00
delayed-ref.h Btrfs: return old and new total ref mods when adding delayed refs 2017-06-29 20:17:01 +02:00
dev-replace.c Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
dev-replace.h btrfs: constify device path passed to relevant helpers 2017-02-28 14:26:07 +01:00
dir-item.c btrfs: fix validation of XATTR_ITEM dir items 2017-06-29 20:06:11 +02:00
disk-io.c Btrfs: disable FUA if mounted with nobarrier 2018-02-25 11:08:00 +01:00
disk-io.h btrfs: use named constant for bdev blocksize 2017-08-16 16:12:04 +02:00
export.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
export.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extent-tree.c btrfs: fix missing error return in btrfs_drop_snapshot 2017-12-14 09:52:54 +01:00
extent_io.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extent_io.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extent_map.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extent_map.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
file-item.c Merge branch 'for-4.13-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux 2017-07-05 16:41:23 -07:00
file.c Btrfs: fix list_add corruption and soft lockups in fsync 2018-02-03 17:39:06 +01:00
free-space-cache.c btrfs: fix deadlock when writing out space cache 2018-02-03 17:39:04 +01:00
free-space-cache.h btrfs: free-space-cache, clean up unnecessary root arguments 2017-02-17 12:03:56 +01:00
free-space-tree.c btrfs: pass fs_info to btrfs_del_root instead of tree_root 2017-08-21 17:49:54 +02:00
free-space-tree.h btrfs: expose internal free space tree routine only if sanity tests are enabled 2017-08-18 16:36:29 +02:00
hash.c crypto: Work around deallocated stack frame reference gcc bug on sparc. 2017-06-08 17:36:03 +08:00
hash.h btrfs: advertise which crc32c implementation is being used at module load 2016-06-06 14:08:28 +02:00
inode-item.c btrfs: take an fs_info directly when the root is not used otherwise 2016-12-06 16:06:59 +01:00
inode-map.c btrfs: qgroup: Introduce extent changeset for qgroup reserve functions 2017-06-29 20:17:02 +02:00
inode-map.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
inode.c btrfs: Fix quota reservation leak on preallocated files 2018-02-25 11:08:00 +01:00
ioctl.c btrfs: Fix possible off-by-one in btrfs_search_path_in_tree 2018-02-25 11:08:00 +01:00
locking.c btrfs: cleanup, remove stray return statements 2016-01-07 14:30:52 +01:00
locking.h
lzo.c btrfs: switch to kvmalloc and GFP_KERNEL in lzo/zlib alloc_workspace 2017-06-19 18:26:02 +02:00
math.h
ordered-data.c btrfs: fix integer overflow in calc_reclaim_items_nr 2017-06-29 20:17:02 +02:00
ordered-data.h btrfs: fix integer overflow in calc_reclaim_items_nr 2017-06-29 20:17:02 +02:00
orphan.c
print-tree.c Btrfs: add one more sanity check for shared ref type 2017-08-21 17:47:43 +02:00
print-tree.h btrfs: get fs_info from eb in btrfs_print_tree, remove argument 2017-08-16 16:12:03 +02:00
props.c Merge branch 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2017-09-14 17:30:49 -07:00
props.h
qgroup.c btrfs: Report error on removing qgroup if del_qgroup_item fails 2017-09-26 14:54:01 +02:00
qgroup.h btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges 2017-06-29 20:17:02 +02:00
raid56.c btrfs: Fix NULL pointer exception in find_bio_stripe 2018-03-21 12:06:44 +01:00
raid56.h btrfs: take an fs_info directly when the root is not used otherwise 2016-12-06 16:06:59 +01:00
rcu-string.h
reada.c btrfs: remove unused member err from reada_extent 2017-06-19 18:25:59 +02:00
relocation.c btrfs: fix NULL pointer dereference from free_reloc_roots() 2017-09-26 14:51:49 +02:00
root-tree.c Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
scrub.c Merge branch 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux 2017-09-09 13:27:51 -07:00
send.c Btrfs: incremental send, fix wrong unlink path after renaming file 2018-02-03 17:39:10 +01:00
send.h Btrfs: use linux/sizes.h to represent constants 2016-01-07 14:38:02 +01:00
struct-funcs.c btrfs: struct-funcs, constify readers 2017-08-16 14:19:53 +02:00
super.c btrfs: avoid null pointer dereference on fs_info when calling btrfs_crit 2017-12-20 10:10:30 +01:00
sysfs.c Revert "btrfs: use proper endianness accessors for super_copy" 2018-03-19 08:42:47 +01:00
sysfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
transaction.c Revert "btrfs: use proper endianness accessors for super_copy" 2018-03-19 08:42:47 +01:00
transaction.h btrfs: remove unused qgroup members from btrfs_trans_handle 2017-04-18 14:07:25 +02:00
tree-defrag.c Btrfs: fix locking bugs when defragging leaves 2015-12-18 02:51:32 +00:00
tree-log.c Btrfs: fix unexpected -EEXIST when creating new inode 2018-02-22 15:42:30 +01:00
tree-log.h btrfs: Make btrfs_del_inode_ref take btrfs_inode 2017-02-14 15:50:54 +01:00
ulist.c btrfs: ulist: rename ulist_fini to ulist_release 2017-02-17 12:03:50 +01:00
ulist.h btrfs: ulist: rename ulist_fini to ulist_release 2017-02-17 12:03:50 +01:00
uuid-tree.c btrfs: return the actual error value from from btrfs_uuid_tree_iterate 2016-12-19 18:08:15 +01:00
volumes.c btrfs: Fix memory barriers usage with device stats counters 2018-03-21 12:06:44 +01:00
volumes.h btrfs: Fix memory barriers usage with device stats counters 2018-03-21 12:06:44 +01:00
xattr.c btrfs: Check name_len with boundary in verify dir_item 2017-06-21 19:16:04 +02:00
xattr.h btrfs: Switch to generic xattr handlers 2016-05-17 19:17:09 -04:00
zlib.c btrfs: switch to kvmalloc and GFP_KERNEL in lzo/zlib alloc_workspace 2017-06-19 18:26:02 +02:00
zstd.c btrfs: Add zstd support 2017-08-15 09:02:09 -07:00