diff options
author | Jan Kara <jack@suse.cz> | 2009-09-22 00:01:06 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 14:17:24 (GMT) |
commit | 580be0837a7a59b207c3d5c661d044d8dd0a6a30 (patch) | |
tree | 4a659c92ed738367c1ed4d9b1b50fe018f401b81 /fs | |
parent | 5be461657be65460ad92be3527e3bb1dd11c49ea (diff) | |
download | linux-fsl-qoriq-580be0837a7a59b207c3d5c661d044d8dd0a6a30.tar.xz |
fs: make sure data stored into inode is properly seen before unlocking new inode
In theory it could happen that on one CPU we initialize a new inode but
clearing of I_NEW | I_LOCK gets reordered before some of the
initialization. Thus on another CPU we return not fully uptodate inode
from iget_locked().
This seems to fix a corruption issue on ext3 mounted over NFS.
[akpm@linux-foundation.org: add some commentary]
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/inode.c | 14 |
1 files changed, 8 insertions, 6 deletions
@@ -695,13 +695,15 @@ void unlock_new_inode(struct inode *inode) } #endif /* - * This is special! We do not need the spinlock - * when clearing I_LOCK, because we're guaranteed - * that nobody else tries to do anything about the - * state of the inode when it is locked, as we - * just created it (so there can be no old holders - * that haven't tested I_LOCK). + * This is special! We do not need the spinlock when clearing I_LOCK, + * because we're guaranteed that nobody else tries to do anything about + * the state of the inode when it is locked, as we just created it (so + * there can be no old holders that haven't tested I_LOCK). + * However we must emit the memory barrier so that other CPUs reliably + * see the clearing of I_LOCK after the other inode initialisation has + * completed. */ + smp_mb(); WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW)); inode->i_state &= ~(I_LOCK|I_NEW); wake_up_inode(inode); |