Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6

[linux-2.6-omap-h63xx.git] / fs / xfs / linux-2.6 / xfs_buf.h

diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index 841d7883528db8df2455ac50c173ba9ddeb97b1c..29d1d4adc07897a7fdb47b76b4deb9fbf4c78e27 100644 (file)
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -66,6 +66,25 @@ typedef enum {
        _XBF_PAGES = (1 << 18),     /* backed by refcounted pages          */
        _XBF_RUN_QUEUES = (1 << 19),/* run block device task queue         */
        _XBF_DELWRI_Q = (1 << 21),   /* buffer on delwri queue             */
+
+       /*
+        * Special flag for supporting metadata blocks smaller than a FSB.
+        *
+        * In this case we can have multiple xfs_buf_t on a single page and
+        * need to lock out concurrent xfs_buf_t readers as they only
+        * serialise access to the buffer.
+        *
+        * If the FSB size >= PAGE_CACHE_SIZE case, we have no serialisation
+        * between reads of the page. Hence we can have one thread read the
+        * page and modify it, but then race with another thread that thinks
+        * the page is not up-to-date and hence reads it again.
+        *
+        * The result is that the first modifcation to the page is lost.
+        * This sort of AGF/AGI reading race can happen when unlinking inodes
+        * that require truncation and results in the AGI unlinked list
+        * modifications being lost.
+        */
+       _XBF_PAGE_LOCKED = (1 << 22),
 } xfs_buf_flags_t;
 
 typedef enum {
@@ -410,7 +429,7 @@ static inline void xfs_bdwrite(void *mp, xfs_buf_t *bp)
  *     Handling of buftargs.
  */
 extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
-extern void xfs_free_buftarg(xfs_buftarg_t *, int);
+extern void xfs_free_buftarg(xfs_buftarg_t *);
 extern void xfs_wait_buftarg(xfs_buftarg_t *);
 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);