xfs: ensure EFD trans aborts on log recovery extent free failure

Log recovery attempts to free extents with leftover EFIs in the AIL
after initial processing. If the extent free fails (e.g., due to
unrelated fs corruption), the transaction is cancelled, though it
might not be dirtied at the time. If this is the case, the EFD does
not abort and thus does not release the EFI. This can lead to hangs
as the EFI pins the AIL.

Update xlog_recover_process_efi() to log the EFD in the transaction
before xfs_free_extent() errors are handled to ensure the
transaction is dirty, aborts the EFD and releases the EFI on error.
Since this is a requirement for EFD processing (and consistent with
xfs_bmap_finish()), update the EFD logging helper to do the extent
free and unconditionally log the EFD. This encodes the required EFD
logging behavior into the helper and reduces the likelihood of
errors down the road.

[dchinner: re-add xfs_alloc.h to xfs_log_recover.c to fix build
 failure.]

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_bmap_util.c

@@ -112,23 +112,16 @@ xfs_bmap_finish(
 		return error;
 	}
 
+	/*
+	 * Get an EFD and free each extent in the list, logging to the EFD in
+	 * the process. The remaining bmap free list is cleaned up by the caller
+	 * on error.
+	 */
 	efd = xfs_trans_get_efd(*tp, efi, flist->xbf_count);
 	for (free = flist->xbf_first; free != NULL; free = next) {
 		next = free->xbfi_next;
 
-		/*
+		error = xfs_trans_free_extent(*tp, efd, free->xbfi_startblock,
-		 * Free the extent and log the EFD to dirty the transaction
-		 * before handling errors. This ensures that the transaction is
-		 * aborted, which:
-		 *
-		 * 1.) releases the EFI and frees the EFD
-		 * 2.) shuts down the filesystem
-		 *
-		 * The bmap free list is cleaned up at a higher level.
-		 */
-		error = xfs_free_extent(*tp, free->xbfi_startblock,
-					free->xbfi_blockcount);
-		xfs_trans_log_efd_extent(*tp, efd, free->xbfi_startblock,
 					      free->xbfi_blockcount);
 		if (error)
 			return error;

fs/xfs/xfs_log_recover.c

@@ -3752,11 +3752,11 @@ xlog_recover_process_efi(
 
 	for (i = 0; i < efip->efi_format.efi_nextents; i++) {
 		extp = &(efip->efi_format.efi_extents[i]);
-		error = xfs_free_extent(tp, extp->ext_start, extp->ext_len);
+		error = xfs_trans_free_extent(tp, efdp, extp->ext_start,
+					      extp->ext_len);
 		if (error)
 			goto abort_error;
-		xfs_trans_log_efd_extent(tp, efdp, extp->ext_start,
+
-					 extp->ext_len);
 	}
 
 	set_bit(XFS_EFI_RECOVERED, &efip->efi_flags);

fs/xfs/xfs_trans.h

@@ -220,9 +220,8 @@ void		xfs_trans_log_efi_extent(xfs_trans_t *,
 struct xfs_efd_log_item	*xfs_trans_get_efd(xfs_trans_t *,
 				  struct xfs_efi_log_item *,
 				  uint);
-void		xfs_trans_log_efd_extent(xfs_trans_t *,
+int		xfs_trans_free_extent(struct xfs_trans *,
-					 struct xfs_efd_log_item *,
+				      struct xfs_efd_log_item *, xfs_fsblock_t,
-					 xfs_fsblock_t,
 				      xfs_extlen_t);
 int		xfs_trans_commit(struct xfs_trans *);
 int		__xfs_trans_roll(struct xfs_trans **, struct xfs_inode *, int *);

fs/xfs/xfs_trans_extfree.c

@@ -25,6 +25,7 @@
 #include "xfs_trans.h"
 #include "xfs_trans_priv.h"
 #include "xfs_extfree_item.h"
+#include "xfs_alloc.h"
 
 /*
  * This routine is called to allocate an "extent free intention"
@@ -108,19 +109,30 @@ xfs_trans_get_efd(xfs_trans_t		*tp,
 }
 
 /*
- * This routine is called to indicate that the described
+ * Free an extent and log it to the EFD. Note that the transaction is marked
- * extent is to be logged as having been freed.  It should
+ * dirty regardless of whether the extent free succeeds or fails to support the
- * be called once for each extent freed.
+ * EFI/EFD lifecycle rules.
  */
-void
+int
-xfs_trans_log_efd_extent(xfs_trans_t		*tp,
+xfs_trans_free_extent(
-			 xfs_efd_log_item_t	*efdp,
+	struct xfs_trans	*tp,
+	struct xfs_efd_log_item	*efdp,
 	xfs_fsblock_t		start_block,
 	xfs_extlen_t		ext_len)
 {
 	uint			next_extent;
-	xfs_extent_t		*extp;
+	struct xfs_extent	*extp;
+	int			error;
 
+	error = xfs_free_extent(tp, start_block, ext_len);
+
+	/*
+	 * Mark the transaction dirty, even on error. This ensures the
+	 * transaction is aborted, which:
+	 *
+	 * 1.) releases the EFI and frees the EFD
+	 * 2.) shuts down the filesystem
+	 */
 	tp->t_flags |= XFS_TRANS_DIRTY;
 	efdp->efd_item.li_desc->lid_flags |= XFS_LID_DIRTY;
 
@@ -130,4 +142,6 @@ xfs_trans_log_efd_extent(xfs_trans_t		*tp,
 	extp->ext_start = start_block;
 	extp->ext_len = ext_len;
 	efdp->efd_next_extent++;
+
+	return error;
 }