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| author | Filipe Manana <fdmanana@gmail.com> | 2014-06-25 22:36:02 +0100 |
|---|---|---|
| committer | Chris Mason <clm@fb.com> | 2014-07-03 07:03:23 -0700 |
| commit | 3cc79392558f1789e5e1d2fce44b681980f403c3 (patch) | |
| tree | f0f71bc0170de156ec9b772ab886fa53c458746d | |
| parent | 472b909ff6f4884d235ef7b9d3847fad5efafbff (diff) | |
| download | linux-modsign-3cc79392558f1789e5e1d2fce44b681980f403c3.tar.gz | |
Btrfs: atomically set inode->i_flags in btrfs_update_iflags
This change is based on the corresponding recent change for ext4:
ext4: atomically set inode->i_flags in ext4_set_inode_flags()
That has the following commit message that applies to btrfs as well:
"Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time."
Replacing EXT4_IMMUTABLE_FL and EXT4_APPEND_FL with BTRFS_INODE_IMMUTABLE
and BTRFS_INODE_APPEND, respectively.
Reviewed-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
| -rw-r--r-- | fs/btrfs/ioctl.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 6ea15469c63f96..02dc64bbf1cb5a 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -136,19 +136,22 @@ static unsigned int btrfs_flags_to_ioctl(unsigned int flags) void btrfs_update_iflags(struct inode *inode) { struct btrfs_inode *ip = BTRFS_I(inode); - - inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); + unsigned int new_fl = 0; if (ip->flags & BTRFS_INODE_SYNC) - inode->i_flags |= S_SYNC; + new_fl |= S_SYNC; if (ip->flags & BTRFS_INODE_IMMUTABLE) - inode->i_flags |= S_IMMUTABLE; + new_fl |= S_IMMUTABLE; if (ip->flags & BTRFS_INODE_APPEND) - inode->i_flags |= S_APPEND; + new_fl |= S_APPEND; if (ip->flags & BTRFS_INODE_NOATIME) - inode->i_flags |= S_NOATIME; + new_fl |= S_NOATIME; if (ip->flags & BTRFS_INODE_DIRSYNC) - inode->i_flags |= S_DIRSYNC; + new_fl |= S_DIRSYNC; + + set_mask_bits(&inode->i_flags, + S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC, + new_fl); } /* |