[PATCH 03/24] xfs: mark inode buffers in cache

[Dave Chinner <david@fromorbit.com>]

From: Dave Chinner <dchinner@redhat.com>

Inode buffers always have write IO callbacks, so by marking them
directly we can avoid needing to attach ->b_iodone functions to
them. This avoids an indirect call, and makes future modifications
much simpler.

This is largely a rearrangement of the code at this point - no IO
completion functionality changes at this point, just how the
code is run is modified.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c       | 18 +++++++++++++-----
 fs/xfs/xfs_buf.h       | 39 ++++++++++++++++++++++++++-------------
 fs/xfs/xfs_buf_item.c  | 42 +++++++++++++++++++++++++++++++-----------
 fs/xfs/xfs_buf_item.h  |  1 +
 fs/xfs/xfs_inode.c     |  2 +-
 fs/xfs/xfs_trans_buf.c |  3 +++
 6 files changed, 75 insertions(+), 30 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 9c2fbb6bbf89d..6105b97028d6a 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -14,6 +14,8 @@
 #include "xfs_mount.h"
 #include "xfs_trace.h"
 #include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_buf_item.h"
 #include "xfs_errortag.h"
 #include "xfs_error.h"
 
@@ -1202,12 +1204,18 @@ xfs_buf_ioend(
 		bp->b_flags |= XBF_DONE;
 	}
 
-	if (bp->b_iodone)
+	/* inodes always have a callback on write */
+	if (!read && (bp->b_flags & _XBF_INODES)) {
+		xfs_buf_inode_iodone(bp);
+		return;
+	}
+
+	if (bp->b_iodone) {
 		(*(bp->b_iodone))(bp);
-	else if (bp->b_flags & XBF_ASYNC)
-		xfs_buf_relse(bp);
-	else
-		complete(&bp->b_iowait);
+		return;
+	}
+
+	xfs_buf_ioend_finish(bp);
 }
 
 static void
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 050c53b739e24..b3e5d653d09f1 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -30,15 +30,19 @@
 #define XBF_STALE	 (1 << 6) /* buffer has been staled, do not find it */
 #define XBF_WRITE_FAIL	 (1 << 7) /* async writes have failed on this buffer */
 
-/* flags used only as arguments to access routines */
-#define XBF_TRYLOCK	 (1 << 16)/* lock requested, but do not wait */
-#define XBF_UNMAPPED	 (1 << 17)/* do not map the buffer */
+/* buffer type flags for write callbacks */
+#define _XBF_INODES	 (1 << 16)/* inode buffer */
 
 /* flags used only internally */
 #define _XBF_PAGES	 (1 << 20)/* backed by refcounted pages */
 #define _XBF_KMEM	 (1 << 21)/* backed by heap memory */
 #define _XBF_DELWRI_Q	 (1 << 22)/* buffer on a delwri queue */
 
+/* flags used only as arguments to access routines */
+#define XBF_TRYLOCK	 (1 << 30)/* lock requested, but do not wait */
+#define XBF_UNMAPPED	 (1 << 31)/* do not map the buffer */
+
+
 typedef unsigned int xfs_buf_flags_t;
 
 #define XFS_BUF_FLAGS \
@@ -50,12 +54,13 @@ typedef unsigned int xfs_buf_flags_t;
 	{ XBF_DONE,		"DONE" }, \
 	{ XBF_STALE,		"STALE" }, \
 	{ XBF_WRITE_FAIL,	"WRITE_FAIL" }, \
-	{ XBF_TRYLOCK,		"TRYLOCK" },	/* should never be set */\
-	{ XBF_UNMAPPED,		"UNMAPPED" },	/* ditto */\
+	{ _XBF_INODES,		"INODES" }, \
 	{ _XBF_PAGES,		"PAGES" }, \
 	{ _XBF_KMEM,		"KMEM" }, \
-	{ _XBF_DELWRI_Q,	"DELWRI_Q" }
-
+	{ _XBF_DELWRI_Q,	"DELWRI_Q" }, \
+	/* The following interface flags should never be set */ \
+	{ XBF_TRYLOCK,		"TRYLOCK" }, \
+	{ XBF_UNMAPPED,		"UNMAPPED" }
 
 /*
  * Internal state flags.
@@ -257,9 +262,23 @@ extern void xfs_buf_unlock(xfs_buf_t *);
 #define xfs_buf_islocked(bp) \
 	((bp)->b_sema.count <= 0)
 
+static inline void xfs_buf_relse(xfs_buf_t *bp)
+{
+	xfs_buf_unlock(bp);
+	xfs_buf_rele(bp);
+}
+
 /* Buffer Read and Write Routines */
 extern int xfs_bwrite(struct xfs_buf *bp);
 extern void xfs_buf_ioend(struct xfs_buf *bp);
+static inline void xfs_buf_ioend_finish(struct xfs_buf *bp)
+{
+	if (bp->b_flags & XBF_ASYNC)
+		xfs_buf_relse(bp);
+	else
+		complete(&bp->b_iowait);
+}
+
 extern void __xfs_buf_ioerror(struct xfs_buf *bp, int error,
 		xfs_failaddr_t failaddr);
 #define xfs_buf_ioerror(bp, err) __xfs_buf_ioerror((bp), (err), __this_address)
@@ -324,12 +343,6 @@ static inline int xfs_buf_ispinned(struct xfs_buf *bp)
 	return atomic_read(&bp->b_pin_count);
 }
 
-static inline void xfs_buf_relse(xfs_buf_t *bp)
-{
-	xfs_buf_unlock(bp);
-	xfs_buf_rele(bp);
-}
-
 static inline int
 xfs_buf_verify_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
 {
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 9e75e8d6042ec..8659cf4282a64 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -1158,20 +1158,15 @@ xfs_buf_iodone_callback_error(
 	return false;
 }
 
-/*
- * This is the iodone() function for buffers which have had callbacks attached
- * to them by xfs_buf_attach_iodone(). We need to iterate the items on the
- * callback list, mark the buffer as having no more callbacks and then push the
- * buffer through IO completion processing.
- */
-void
-xfs_buf_iodone_callbacks(
+static void
+xfs_buf_run_callbacks(
 	struct xfs_buf		*bp)
 {
+
 	/*
-	 * If there is an error, process it. Some errors require us
-	 * to run callbacks after failure processing is done so we
-	 * detect that and take appropriate action.
+	 * If there is an error, process it. Some errors require us to run
+	 * callbacks after failure processing is done so we detect that and take
+	 * appropriate action.
 	 */
 	if (bp->b_error && xfs_buf_iodone_callback_error(bp))
 		return;
@@ -1188,9 +1183,34 @@ xfs_buf_iodone_callbacks(
 	bp->b_log_item = NULL;
 	list_del_init(&bp->b_li_list);
 	bp->b_iodone = NULL;
+}
+
+/*
+ * This is the iodone() function for buffers which have had callbacks attached
+ * to them by xfs_buf_attach_iodone(). We need to iterate the items on the
+ * callback list, mark the buffer as having no more callbacks and then push the
+ * buffer through IO completion processing.
+ */
+void
+xfs_buf_iodone_callbacks(
+	struct xfs_buf		*bp)
+{
+	xfs_buf_run_callbacks(bp);
 	xfs_buf_ioend(bp);
 }
 
+/*
+ * Inode buffer iodone callback function.
+ */
+void
+xfs_buf_inode_iodone(
+	struct xfs_buf		*bp)
+{
+	xfs_buf_run_callbacks(bp);
+	xfs_buf_ioend_finish(bp);
+}
+
+
 /*
  * This is the iodone() function for buffers which have been
  * logged.  It is called when they are eventually flushed out.
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index c9c57e2da9327..a342933ad9b8d 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -59,6 +59,7 @@ void	xfs_buf_attach_iodone(struct xfs_buf *,
 			      struct xfs_log_item *);
 void	xfs_buf_iodone_callbacks(struct xfs_buf *);
 void	xfs_buf_iodone(struct xfs_buf *, struct xfs_log_item *);
+void	xfs_buf_inode_iodone(struct xfs_buf *);
 bool	xfs_buf_log_check_iovec(struct xfs_log_iovec *iovec);
 
 extern kmem_zone_t	*xfs_buf_item_zone;
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 57781c0dbbec5..607c9d9bb2b40 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3841,13 +3841,13 @@ xfs_iflush_int(
 	 * completion on the buffer to remove the inode from the AIL and release
 	 * the flush lock.
 	 */
+	bp->b_flags |= _XBF_INODES;
 	xfs_buf_attach_iodone(bp, xfs_iflush_done, &iip->ili_item);
 
 	/* generate the checksum. */
 	xfs_dinode_calc_crc(mp, dip);
 
 	ASSERT(!list_empty(&bp->b_li_list));
-	ASSERT(bp->b_iodone != NULL);
 	return error;
 }
 
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 08174ffa21189..552d0869aa0fe 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -626,6 +626,7 @@ xfs_trans_inode_buf(
 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
 
 	bip->bli_flags |= XFS_BLI_INODE_BUF;
+	bp->b_flags |= _XBF_INODES;
 	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DINO_BUF);
 }
 
@@ -651,6 +652,7 @@ xfs_trans_stale_inode_buf(
 
 	bip->bli_flags |= XFS_BLI_STALE_INODE;
 	bip->bli_item.li_cb = xfs_buf_iodone;
+	bp->b_flags |= _XBF_INODES;
 	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DINO_BUF);
 }
 
@@ -675,6 +677,7 @@ xfs_trans_inode_alloc_buf(
 	ASSERT(atomic_read(&bip->bli_refcount) > 0);
 
 	bip->bli_flags |= XFS_BLI_INODE_ALLOC_BUF;
+	bp->b_flags |= _XBF_INODES;
 	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DINO_BUF);
 }
 
-- 
2.26.2.761.g0e0b3e54be