Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6

[sfrench/cifs-2.6.git] / fs / xfs / linux-2.6 / xfs_buf.c

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index f01de3c55c43e8ed7effa08d8b5a324e18c4bd2a..649ade8ef598693e2e57ac66475c1993b57903e3 100644 (file)
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -37,6 +37,7 @@
 
 #include "xfs_sb.h"
 #include "xfs_inum.h"
+#include "xfs_log.h"
 #include "xfs_ag.h"
 #include "xfs_dmapi.h"
 #include "xfs_mount.h"
@@ -850,6 +851,12 @@ xfs_buf_lock_value(
  *     Note that this in no way locks the underlying pages, so it is only
  *     useful for synchronizing concurrent use of buffer objects, not for
  *     synchronizing independent access to the underlying pages.
+ *
+ *     If we come across a stale, pinned, locked buffer, we know that we
+ *     are being asked to lock a buffer that has been reallocated. Because
+ *     it is pinned, we know that the log has not been pushed to disk and
+ *     hence it will still be locked. Rather than sleeping until someone
+ *     else pushes the log, push it ourselves before trying to get the lock.
  */
 void
 xfs_buf_lock(
@@ -857,6 +864,8 @@ xfs_buf_lock(
 {
        trace_xfs_buf_lock(bp, _RET_IP_);
 
+       if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
+               xfs_log_force(bp->b_mount, 0);
        if (atomic_read(&bp->b_io_remaining))
                blk_run_address_space(bp->b_target->bt_mapping);
        down(&bp->b_sema);