* [PATCH] Btrfs: atomically set inode->i_flags in btrfs_update_iflags
@ 2014-06-25 21:36 Filipe David Borba Manana
2014-07-01 23:56 ` David Sterba
0 siblings, 1 reply; 3+ messages in thread
From: Filipe David Borba Manana @ 2014-06-25 21:36 UTC (permalink / raw)
To: linux-btrfs; +Cc: Filipe David Borba Manana
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.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
fs/btrfs/ioctl.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6ea1546..02dc64b 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);
}
/*
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Btrfs: atomically set inode->i_flags in btrfs_update_iflags
2014-06-25 21:36 [PATCH] Btrfs: atomically set inode->i_flags in btrfs_update_iflags Filipe David Borba Manana
@ 2014-07-01 23:56 ` David Sterba
2014-07-02 0:25 ` Satoru Takeuchi
0 siblings, 1 reply; 3+ messages in thread
From: David Sterba @ 2014-07-01 23:56 UTC (permalink / raw)
To: Filipe David Borba Manana; +Cc: linux-btrfs
On Wed, Jun 25, 2014 at 10:36:02PM +0100, Filipe David Borba Manana wrote:
> 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.
>
> Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Btrfs: atomically set inode->i_flags in btrfs_update_iflags
2014-07-01 23:56 ` David Sterba
@ 2014-07-02 0:25 ` Satoru Takeuchi
0 siblings, 0 replies; 3+ messages in thread
From: Satoru Takeuchi @ 2014-07-02 0:25 UTC (permalink / raw)
To: dsterba, Filipe David Borba Manana, linux-btrfs
(2014/07/02 8:56), David Sterba wrote:
> On Wed, Jun 25, 2014 at 10:36:02PM +0100, Filipe David Borba Manana wrote:
>> 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.
>>
>> Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
>
> Reviewed-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-07-02 0:34 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2014-06-25 21:36 [PATCH] Btrfs: atomically set inode->i_flags in btrfs_update_iflags Filipe David Borba Manana
2014-07-01 23:56 ` David Sterba
2014-07-02 0:25 ` Satoru Takeuchi
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