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| author | Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com> | 2020-03-06 12:22:43 +0530 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-03-23 17:01:53 +0100 |
| commit | 29566c9c773456467933ee22bbca1c2b72a3506c (patch) | |
| tree | e89c7362de88a359eeea927549e1ba32083bd944 /fs/btrfs | |
| parent | 65cd6d9e30fa85922cb073625665807130d01e70 (diff) | |
| download | linux-rpi-29566c9c773456467933ee22bbca1c2b72a3506c.tar.gz linux-rpi-29566c9c773456467933ee22bbca1c2b72a3506c.tar.bz2 linux-rpi-29566c9c773456467933ee22bbca1c2b72a3506c.zip | |
btrfs: add RCU locks around block group initialization
The space_info list is normally RCU protected and should be traversed
with rcu_read_lock held. There's a warning
[29.104756] WARNING: suspicious RCU usage
[29.105046] 5.6.0-rc4-next-20200305 #1 Not tainted
[29.105231] -----------------------------
[29.105401] fs/btrfs/block-group.c:2011 RCU-list traversed in non-reader section!!
pointing out that the locking is missing in btrfs_read_block_groups.
However this is not necessary as the list traversal happens at mount
time when there's no other thread potentially accessing the list.
To fix the warning and for consistency let's add the RCU lock/unlock,
the code won't be affected much as it's doing some lightweight
operations.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/block-group.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index b8f39a679064..786849fcc319 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -2008,6 +2008,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) btrfs_release_path(path); } + rcu_read_lock(); list_for_each_entry_rcu(space_info, &info->space_info, list) { if (!(btrfs_get_alloc_profile(info, space_info->flags) & (BTRFS_BLOCK_GROUP_RAID10 | @@ -2028,6 +2029,7 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info) list) inc_block_group_ro(cache, 1); } + rcu_read_unlock(); btrfs_init_global_block_rsv(info); ret = check_chunk_block_group_mappings(info); |