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authorFilipe Manana <fdmanana@gmail.com>2014-06-26 01:36:02 +0400
committerChris Mason <clm@fb.com>2014-07-03 18:03:23 +0400
commit3cc79392558f1789e5e1d2fce44b681980f403c3 (patch)
treef0f71bc0170de156ec9b772ab886fa53c458746d /fs
parent472b909ff6f4884d235ef7b9d3847fad5efafbff (diff)
downloadlinux-3cc79392558f1789e5e1d2fce44b681980f403c3.tar.xz
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ioctl.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6ea15469c63f..02dc64bbf1cb 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);
}
/*