Merge tag 'for-linus-v3.9-rc4' of git://oss.sgi.com/xfs/xfs

Pull XFS fixes from Ben Myers:

 - Fix for a potential infinite loop which was introduced in commit
   4d559a3bcb73 ("xfs: limit speculative prealloc near ENOSPC
   thresholds")

 - Fix for the return type of xfs_iomap_eof_prealloc_initial_size from
   commit a1e16c26660b ("xfs: limit speculative prealloc size on sparse
   files")

 - Fix for a failed buffer readahead causing subsequent callers to fail
   incorrectly

* tag 'for-linus-v3.9-rc4' of git://oss.sgi.com/xfs/xfs:
  xfs: ensure we capture IO errors correctly
  xfs: fix xfs_iomap_eof_prealloc_initial_size type
  xfs: fix potential infinite loop in xfs_iomap_prealloc_size()

2 files changed, 8 insertions, 2 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 4e8f0df82d02..8459b5d8cb71 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1334,6 +1334,12 @@ _xfs_buf_ioapply(
         int             size;
         int             i;
 
+        /*
+         * Make sure we capture only current IO errors rather than stale errors
+         * left over from previous use of the buffer (e.g. failed readahead).
+         */
+        bp->b_error = 0;
+
         if (bp->b_flags & XBF_WRITE) {
                 if (bp->b_flags & XBF_SYNCIO)
                         rw = WRITE_SYNC;
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 912d83d8860a..5a30dd899d2b 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -325,7 +325,7 @@ xfs_iomap_eof_want_preallocate(
  * rather than falling short due to things like stripe unit/width alignment of
  * real extents.
  */
-STATIC int
+STATIC xfs_fsblock_t
 xfs_iomap_eof_prealloc_initial_size(
         struct xfs_mount        *mp,
         struct xfs_inode        *ip,
@@ -413,7 +413,7 @@ xfs_iomap_prealloc_size(
                  * have a large file on a small filesystem and the above
                  * lowspace thresholds are smaller than MAXEXTLEN.
                  */
-                while (alloc_blocks >= freesp)
+                while (alloc_blocks && alloc_blocks >= freesp)
                         alloc_blocks >>= 4;
         }