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authorDave Chinner <david@fromorbit.com>2008-11-17 17:37:10 +1100
committerLachlan McIlroy <lachlan@redback.melbourne.sgi.com>2008-11-17 17:37:10 +1100
commitcc09c0dc57de7f7d2ed89d480b5653e5f6a32f2c (patch)
tree3c6145ccb00f603c47e020cfa45f159ab76cf9bf /fs/xfs/xfs_trans.c
parent6307091fe69ae74747298bdcaf43119ad67bda3a (diff)
[XFS] Fix double free of log tickets
When an I/O error occurs during an intermediate commit on a rolling transaction, xfs_trans_commit() will free the transaction structure and the related ticket. However, the duplicate transaction that gets used as the transaction continues still contains a pointer to the ticket. Hence when the duplicate transaction is cancelled and freed, we free the ticket a second time. Add reference counting to the ticket so that we hold an extra reference to the ticket over the transaction commit. We drop the extra reference once we have checked that the transaction commit did not return an error, thus avoiding a double free on commit error. Credit to Nick Piggin for tripping over the problem. SGI-PV: 989741 Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_trans.c')
-rw-r--r--fs/xfs/xfs_trans.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index ad137efc870..8570b826fed 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -290,7 +290,7 @@ xfs_trans_dup(
ASSERT(tp->t_ticket != NULL);
ntp->t_flags = XFS_TRANS_PERM_LOG_RES | (tp->t_flags & XFS_TRANS_RESERVE);
- ntp->t_ticket = tp->t_ticket;
+ ntp->t_ticket = xfs_log_ticket_get(tp->t_ticket);
ntp->t_blk_res = tp->t_blk_res - tp->t_blk_res_used;
tp->t_blk_res = tp->t_blk_res_used;
ntp->t_rtx_res = tp->t_rtx_res - tp->t_rtx_res_used;
@@ -1260,6 +1260,13 @@ xfs_trans_roll(
trans = *tpp;
/*
+ * transaction commit worked ok so we can drop the extra ticket
+ * reference that we gained in xfs_trans_dup()
+ */
+ xfs_log_ticket_put(trans->t_ticket);
+
+
+ /*
* Reserve space in the log for th next transaction.
* This also pushes items in the "AIL", the list of logged items,
* out to disk if they are taking up space at the tail of the log