Merge tag 'xfs-5.0-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "Here are a handful of XFS fixes to fix a data corruption problem, a
  crasher bug, and a deadlock.

  Summary:

   - Fix cache coherency problem with writeback mappings

   - Fix buffer deadlock when shutting fs down

   - Fix a null pointer dereference when running online repair"

* tag 'xfs-5.0-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: set buffer ops when repair probes for btree type
  xfs: end sync buffer I/O properly on shutdown error
  xfs: eof trim writeback mapping as soon as it is cached

3 files changed, 27 insertions, 5 deletions

diff --git a/fs/xfs/scrub/repair.c b/fs/xfs/scrub/repair.c
index 1c8eecfe52b8..6acf1bfa0bfe 100644
--- a/fs/xfs/scrub/repair.c
+++ b/fs/xfs/scrub/repair.c
@@ -768,18 +768,23 @@ xrep_findroot_block(
                 if (!uuid_equal(&btblock->bb_u.s.bb_uuid,
                                 &mp->m_sb.sb_meta_uuid))
                         goto out;
+                /*
+                 * Read verifiers can reference b_ops, so we set the pointer
+                 * here.  If the verifier fails we'll reset the buffer state
+                 * to what it was before we touched the buffer.
+                 */
+                bp->b_ops = fab->buf_ops;
                 fab->buf_ops->verify_read(bp);
                 if (bp->b_error) {
+                        bp->b_ops = NULL;
                         bp->b_error = 0;
                         goto out;
                 }
 
                 /*
                  * Some read verifiers will (re)set b_ops, so we must be
-                 * careful not to blow away any such assignment.
+                 * careful not to change b_ops after running the verifier.
                  */
-                if (!bp->b_ops)
-                        bp->b_ops = fab->buf_ops;
         }
 
         /*
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 338b9d9984e0..d9048bcea49c 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -449,6 +449,7 @@ xfs_map_blocks(
         }
 
         wpc->imap = imap;
+        xfs_trim_extent_eof(&wpc->imap, ip);
         trace_xfs_map_blocks_found(ip, offset, count, wpc->io_type, &imap);
         return 0;
 allocate_blocks:
@@ -459,6 +460,7 @@ allocate_blocks:
         ASSERT(whichfork == XFS_COW_FORK || cow_fsb == NULLFILEOFF ||
                imap.br_startoff + imap.br_blockcount <= cow_fsb);
         wpc->imap = imap;
+        xfs_trim_extent_eof(&wpc->imap, ip);
         trace_xfs_map_blocks_alloc(ip, offset, count, wpc->io_type, &imap);
         return 0;
 }
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index eedc5e0156ff..4f5f2ff3f70f 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -776,10 +776,26 @@ _xfs_buf_read(
 }
 
 /*
+ * Set buffer ops on an unchecked buffer and validate it, if possible.
+ *
  * If the caller passed in an ops structure and the buffer doesn't have ops
  * assigned, set the ops and use them to verify the contents.  If the contents
  * cannot be verified, we'll clear XBF_DONE.  We assume the buffer has no
  * recorded errors and is already in XBF_DONE state.
+ *
+ * Under normal operations, every in-core buffer must have buffer ops assigned
+ * to them when the buffer is read in from disk so that we can validate the
+ * metadata.
+ *
+ * However, there are two scenarios where one can encounter in-core buffers
+ * that don't have buffer ops.  The first is during log recovery of buffers on
+ * a V4 filesystem, though these buffers are purged at the end of recovery.
+ *
+ * The other is online repair, which tries to match arbitrary metadata blocks
+ * with btree types in order to find the root.  If online repair doesn't match
+ * the buffer with /any/ btree type, the buffer remains in memory in DONE state
+ * with no ops, and a subsequent read_buf call from elsewhere will not set the
+ * ops.  This function helps us fix this situation.
  */
 int
 xfs_buf_ensure_ops(
@@ -1536,8 +1552,7 @@ __xfs_buf_submit(
                 xfs_buf_ioerror(bp, -EIO);
                 bp->b_flags &= ~XBF_DONE;
                 xfs_buf_stale(bp);
-                if (bp->b_flags & XBF_ASYNC)
-                        xfs_buf_ioend(bp);
+                xfs_buf_ioend(bp);
                 return -EIO;
         }