xfs: clean up xfs_bui_item_recover iget/trans_alloc/ilock ordering

BugLink: https://bugs.launchpad.net/bugs/2011625

commit 64a3f33 upstream.

In most places in XFS, we have a specific order in which we gather
resources: grab the inode, allocate a transaction, then lock the inode.
xfs_bui_item_recover doesn't do it in that order, so fix it to be more
consistent.  This also makes the error bailout code a bit less weird.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luke Nowakowski-Krijger <luke.nowakowskikrijger@canonical.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

Author: djwong

fs/xfs/xfs_bmap_item.c

@@ -22,6 +22,7 @@
 #include "xfs_bmap_btree.h"
 #include "xfs_trans_space.h"
 #include "xfs_error.h"
+#include "xfs_quota.h"
 
 kmem_zone_t	*xfs_bui_zone;
 kmem_zone_t	*xfs_bud_zone;
@@ -488,29 +489,34 @@ xfs_bui_recover(
 		return -EFSCORRUPTED;
 	}
 
-	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate,
-			XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), 0, 0, &tp);
+	/* Grab the inode. */
+	error = xfs_iget(mp, NULL, bmap->me_owner, 0, 0, &ip);
 	if (error)
 		return error;
 
-	budp = xfs_trans_get_bud(tp, buip);
-
-	/* Grab the inode. */
-	error = xfs_iget(mp, tp, bmap->me_owner, 0, XFS_ILOCK_EXCL, &ip);
+	error = xfs_qm_dqattach(ip);
 	if (error)
-		goto err_inode;
+		goto err_rele;
 
 	if (VFS_I(ip)->i_nlink == 0)
 		xfs_iflags_set(ip, XFS_IRECOVERY);
 
+	/* Allocate transaction and do the work. */
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate,
+			XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), 0, 0, &tp);
+	if (error)
+		goto err_rele;
+
+	budp = xfs_trans_get_bud(tp, buip);
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, 0);
 
 	count = bmap->me_len;
 	error = xfs_trans_log_finish_bmap_update(tp, budp, bui_type, ip,
 			whichfork, bmap->me_startoff, bmap->me_startblock,
 			&count, state);
 	if (error)
-		goto err_inode;
+		goto err_cancel;
 
 	if (count > 0) {
 		ASSERT(bui_type == XFS_BMAP_UNMAP);
@@ -522,16 +528,20 @@ xfs_bui_recover(
 	}
 
 	set_bit(XFS_BUI_RECOVERED, &buip->bui_flags);
+	/* Commit transaction, which frees the transaction. */
 	error = xfs_defer_ops_capture_and_commit(tp, capture_list);
+	if (error)
+		goto err_unlock;
+
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	xfs_irele(ip);
-	return error;
+	return 0;
 
-err_inode:
+err_cancel:
 	xfs_trans_cancel(tp);
-	if (ip) {
-		xfs_iunlock(ip, XFS_ILOCK_EXCL);
-		xfs_irele(ip);
-	}
+err_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+err_rele:
+	xfs_irele(ip);
 	return error;
 }