xfs: Ensure inode allocation buffers are fully replayed

With delayed logging, we can get inode allocation buffers in the
same transaction inode unlink buffers. We don't currently mark inode
allocation buffers in the log, so inode unlink buffers take
precedence over allocation buffers.

The result is that when they are combined into the same checkpoint,
only the unlinked inode chain fields are replayed, resulting in
uninitialised inode buffers being detected when the next inode
modification is replayed.

To fix this, we need to ensure that we do not set the inode buffer
flag in the buffer log item format flags if the inode allocation has
not already hit the log. To avoid requiring a change to log
recovery, we really need to make this a modification that relies
only on in-memory sate.

We can do this by checking during buffer log formatting (while the
CIL cannot be flushed) if we are still in the same sequence when we
commit the unlink transaction as the inode allocation transaction.
If we are, then we do not add the inode buffer flag to the buffer
log format item flags. This means the entire buffer will be
replayed, not just the unlinked fields. We do this while
CIL flusheѕ are locked out to ensure that we don't race with the
sequence numbers changing and hence fail to put the inode buffer
flag in the buffer format flags when we really need to.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index 8cbb82b1d95c..f20bb472d582 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -69,6 +69,7 @@ typedef struct xfs_buf_log_format {
 #define XFS_BLI_LOGGED          0x08
 #define XFS_BLI_INODE_ALLOC_BUF 0x10
 #define XFS_BLI_STALE_INODE     0x20
+#define XFS_BLI_INODE_BUF       0x40
 
 #define XFS_BLI_FLAGS \
         { XFS_BLI_HOLD,         "HOLD" }, \
@@ -76,7 +77,8 @@ typedef struct xfs_buf_log_format {
         { XFS_BLI_STALE,        "STALE" }, \
         { XFS_BLI_LOGGED,       "LOGGED" }, \
         { XFS_BLI_INODE_ALLOC_BUF, "INODE_ALLOC" }, \
-        { XFS_BLI_STALE_INODE,  "STALE_INODE" }
+        { XFS_BLI_STALE_INODE,  "STALE_INODE" }, \
+        { XFS_BLI_INODE_BUF,    "INODE_BUF" }
 
 
 #ifdef __KERNEL__