Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 68 insertions, 111 deletions

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 2686d0d54c5b..98c6f73b6752 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -141,8 +141,7 @@ xfs_buf_item_log_check(
 #define         xfs_buf_item_log_check(x)
 #endif
 
-STATIC void     xfs_buf_error_relse(xfs_buf_t *bp);
-STATIC void     xfs_buf_do_callbacks(xfs_buf_t *bp, xfs_log_item_t *lip);
+STATIC void     xfs_buf_do_callbacks(struct xfs_buf *bp);
 
 /*
  * This returns the number of log iovecs needed to log the
@@ -450,7 +449,7 @@ xfs_buf_item_unpin(
                  * xfs_trans_ail_delete() drops the AIL lock.
                  */
                 if (bip->bli_flags & XFS_BLI_STALE_INODE) {
-                        xfs_buf_do_callbacks(bp, (xfs_log_item_t *)bip);
+                        xfs_buf_do_callbacks(bp);
                         XFS_BUF_SET_FSPRIVATE(bp, NULL);
                         XFS_BUF_CLR_IODONE_FUNC(bp);
                 } else {
@@ -918,15 +917,26 @@ xfs_buf_attach_iodone(
         XFS_BUF_SET_IODONE_FUNC(bp, xfs_buf_iodone_callbacks);
 }
 
+/*
+ * We can have many callbacks on a buffer. Running the callbacks individually
+ * can cause a lot of contention on the AIL lock, so we allow for a single
+ * callback to be able to scan the remaining lip->li_bio_list for other items
+ * of the same type and callback to be processed in the first call.
+ *
+ * As a result, the loop walking the callback list below will also modify the
+ * list. it removes the first item from the list and then runs the callback.
+ * The loop then restarts from the new head of the list. This allows the
+ * callback to scan and modify the list attached to the buffer and we don't
+ * have to care about maintaining a next item pointer.
+ */
 STATIC void
 xfs_buf_do_callbacks(
-        xfs_buf_t       *bp,
-        xfs_log_item_t  *lip)
+        struct xfs_buf          *bp)
 {
-        xfs_log_item_t  *nlip;
+        struct xfs_log_item     *lip;
 
-        while (lip != NULL) {
-                nlip = lip->li_bio_list;
+        while ((lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *)) != NULL) {
+                XFS_BUF_SET_FSPRIVATE(bp, lip->li_bio_list);
                 ASSERT(lip->li_cb != NULL);
                 /*
                  * Clear the next pointer so we don't have any
@@ -936,7 +946,6 @@ xfs_buf_do_callbacks(
                  */
                 lip->li_bio_list = NULL;
                 lip->li_cb(bp, lip);
-                lip = nlip;
         }
 }
 
@@ -949,128 +958,76 @@ xfs_buf_do_callbacks(
  */
 void
 xfs_buf_iodone_callbacks(
-        xfs_buf_t       *bp)
+        struct xfs_buf          *bp)
 {
-        xfs_log_item_t  *lip;
-        static ulong    lasttime;
-        static xfs_buftarg_t *lasttarg;
-        xfs_mount_t     *mp;
+        struct xfs_log_item     *lip = bp->b_fspriv;
+        struct xfs_mount        *mp = lip->li_mountp;
+        static ulong            lasttime;
+        static xfs_buftarg_t    *lasttarg;
 
-        ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
-        lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
+        if (likely(!XFS_BUF_GETERROR(bp)))
+                goto do_callbacks;
 
-        if (XFS_BUF_GETERROR(bp) != 0) {
-                /*
-                 * If we've already decided to shutdown the filesystem
-                 * because of IO errors, there's no point in giving this
-                 * a retry.
-                 */
-                mp = lip->li_mountp;
-                if (XFS_FORCED_SHUTDOWN(mp)) {
-                        ASSERT(XFS_BUF_TARGET(bp) == mp->m_ddev_targp);
-                        XFS_BUF_SUPER_STALE(bp);
-                        trace_xfs_buf_item_iodone(bp, _RET_IP_);
-                        xfs_buf_do_callbacks(bp, lip);
-                        XFS_BUF_SET_FSPRIVATE(bp, NULL);
-                        XFS_BUF_CLR_IODONE_FUNC(bp);
-                        xfs_buf_ioend(bp, 0);
-                        return;
-                }
+        /*
+         * If we've already decided to shutdown the filesystem because of
+         * I/O errors, there's no point in giving this a retry.
+         */
+        if (XFS_FORCED_SHUTDOWN(mp)) {
+                XFS_BUF_SUPER_STALE(bp);
+                trace_xfs_buf_item_iodone(bp, _RET_IP_);
+                goto do_callbacks;
+        }
 
-                if ((XFS_BUF_TARGET(bp) != lasttarg) ||
-                    (time_after(jiffies, (lasttime + 5*HZ)))) {
-                        lasttime = jiffies;
-                        cmn_err(CE_ALERT, "Device %s, XFS metadata write error"
-                                        " block 0x%llx in %s",
-                                XFS_BUFTARG_NAME(XFS_BUF_TARGET(bp)),
-                              (__uint64_t)XFS_BUF_ADDR(bp), mp->m_fsname);
-                }
-                lasttarg = XFS_BUF_TARGET(bp);
+        if (XFS_BUF_TARGET(bp) != lasttarg ||
+            time_after(jiffies, (lasttime + 5*HZ))) {
+                lasttime = jiffies;
+                cmn_err(CE_ALERT, "Device %s, XFS metadata write error"
+                                " block 0x%llx in %s",
+                        XFS_BUFTARG_NAME(XFS_BUF_TARGET(bp)),
+                      (__uint64_t)XFS_BUF_ADDR(bp), mp->m_fsname);
+        }
+        lasttarg = XFS_BUF_TARGET(bp);
 
-                if (XFS_BUF_ISASYNC(bp)) {
-                        /*
-                         * If the write was asynchronous then noone will be
-                         * looking for the error.  Clear the error state
-                         * and write the buffer out again delayed write.
-                         *
-                         * XXXsup This is OK, so long as we catch these
-                         * before we start the umount; we don't want these
-                         * DELWRI metadata bufs to be hanging around.
-                         */
-                        XFS_BUF_ERROR(bp,0); /* errno of 0 unsets the flag */
-
-                        if (!(XFS_BUF_ISSTALE(bp))) {
-                                XFS_BUF_DELAYWRITE(bp);
-                                XFS_BUF_DONE(bp);
-                                XFS_BUF_SET_START(bp);
-                        }
-                        ASSERT(XFS_BUF_IODONE_FUNC(bp));
-                        trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
-                        xfs_buf_relse(bp);
-                } else {
-                        /*
-                         * If the write of the buffer was not asynchronous,
-                         * then we want to make sure to return the error
-                         * to the caller of bwrite().  Because of this we
-                         * cannot clear the B_ERROR state at this point.
-                         * Instead we install a callback function that
-                         * will be called when the buffer is released, and
-                         * that routine will clear the error state and
-                         * set the buffer to be written out again after
-                         * some delay.
-                         */
-                        /* We actually overwrite the existing b-relse
-                           function at times, but we're gonna be shutting down
-                           anyway. */
-                        XFS_BUF_SET_BRELSE_FUNC(bp,xfs_buf_error_relse);
+        /*
+         * If the write was asynchronous then noone will be looking for the
+         * error.  Clear the error state and write the buffer out again.
+         *
+         * During sync or umount we'll write all pending buffers again
+         * synchronous, which will catch these errors if they keep hanging
+         * around.
+         */
+        if (XFS_BUF_ISASYNC(bp)) {
+                XFS_BUF_ERROR(bp, 0); /* errno of 0 unsets the flag */
+
+                if (!XFS_BUF_ISSTALE(bp)) {
+                        XFS_BUF_DELAYWRITE(bp);
                         XFS_BUF_DONE(bp);
-                        XFS_BUF_FINISH_IOWAIT(bp);
+                        XFS_BUF_SET_START(bp);
                 }
+                ASSERT(XFS_BUF_IODONE_FUNC(bp));
+                trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
+                xfs_buf_relse(bp);
                 return;
         }
 
-        xfs_buf_do_callbacks(bp, lip);
-        XFS_BUF_SET_FSPRIVATE(bp, NULL);
-        XFS_BUF_CLR_IODONE_FUNC(bp);
-        xfs_buf_ioend(bp, 0);
-}
-
-/*
- * This is a callback routine attached to a buffer which gets an error
- * when being written out synchronously.
- */
-STATIC void
-xfs_buf_error_relse(
-        xfs_buf_t       *bp)
-{
-        xfs_log_item_t  *lip;
-        xfs_mount_t     *mp;
-
-        lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
-        mp = (xfs_mount_t *)lip->li_mountp;
-        ASSERT(XFS_BUF_TARGET(bp) == mp->m_ddev_targp);
-
+        /*
+         * If the write of the buffer was synchronous, we want to make
+         * sure to return the error to the caller of xfs_bwrite().
+         */
         XFS_BUF_STALE(bp);
         XFS_BUF_DONE(bp);
         XFS_BUF_UNDELAYWRITE(bp);
-        XFS_BUF_ERROR(bp,0);
 
         trace_xfs_buf_error_relse(bp, _RET_IP_);
+        xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
 
-        if (! XFS_FORCED_SHUTDOWN(mp))
-                xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
-        /*
-         * We have to unpin the pinned buffers so do the
-         * callbacks.
-         */
-        xfs_buf_do_callbacks(bp, lip);
+do_callbacks:
+        xfs_buf_do_callbacks(bp);
         XFS_BUF_SET_FSPRIVATE(bp, NULL);
         XFS_BUF_CLR_IODONE_FUNC(bp);
-        XFS_BUF_SET_BRELSE_FUNC(bp,NULL);
-        xfs_buf_relse(bp);
+        xfs_buf_ioend(bp, 0);
 }
 
-
 /*
  * This is the iodone() function for buffers which have been
  * logged.  It is called when they are eventually flushed out.