projects / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 2cb7cef9 BS |
1 | From: Jan Kara <jack@suse.cz> |
| 2 | Subject: ocfs2: Fix possible deadlock in ocfs2_global_read_dquot() | |
| 3 | Patch-mainline: 2.6.31 | |
| 4 | ||
| 5 | It is not possible to get a read lock and then try to get the same write lock | |
| 6 | in one thread as that can block on downconvert being requested by other node | |
| 7 | leading to deadlock. So first drop the quota lock for reading and only after | |
| 8 | that get it for writing. | |
| 9 | ||
| 10 | Signed-off-by: Jan Kara <jack@suse.cz> | |
| 11 | --- | |
| 12 | fs/ocfs2/quota_global.c | 4 +++- | |
| 13 | 1 file changed, 3 insertions(+), 1 deletion(-) | |
| 14 | ||
| 15 | --- a/fs/ocfs2/quota_global.c | |
| 16 | +++ b/fs/ocfs2/quota_global.c | |
| 17 | @@ -354,6 +354,7 @@ int ocfs2_global_read_dquot(struct dquot | |
| 18 | OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes; | |
| 19 | if (!dquot->dq_off) { /* No real quota entry? */ | |
| 20 | /* Upgrade to exclusive lock for allocation */ | |
| 21 | + ocfs2_qinfo_unlock(info, 0); | |
| 22 | err = ocfs2_qinfo_lock(info, 1); | |
| 23 | if (err < 0) | |
| 24 | goto out_qlock; | |
| 25 | @@ -368,7 +369,8 @@ int ocfs2_global_read_dquot(struct dquot | |
| 26 | out_qlock: | |
| 27 | if (ex) | |
| 28 | ocfs2_qinfo_unlock(info, 1); | |
| 29 | - ocfs2_qinfo_unlock(info, 0); | |
| 30 | + else | |
| 31 | + ocfs2_qinfo_unlock(info, 0); | |
| 32 | out: | |
| 33 | if (err < 0) | |
| 34 | mlog_errno(err); |