1 files changed, 37 insertions, 44 deletions

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 5d29aa17475e..8f7da5877fa3 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1672,6 +1672,30 @@ xfs_swap_extents_check_format(
 }
 
 int
+xfs_swap_extent_flush(
+        struct xfs_inode        *ip)
+{
+        int     error;
+
+        error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
+        if (error)
+                return error;
+        truncate_pagecache_range(VFS_I(ip), 0, -1);
+
+        /* Verify O_DIRECT for ftmp */
+        if (VFS_I(ip)->i_mapping->nrpages)
+                return -EINVAL;
+
+        /*
+         * Don't try to swap extents on mmap()d files because we can't lock
+         * out races against page faults safely.
+         */
+        if (mapping_mapped(VFS_I(ip)->i_mapping))
+                return -EBUSY;
+        return 0;
+}
+
+int
 xfs_swap_extents(
         xfs_inode_t     *ip,    /* target inode */
         xfs_inode_t     *tip,   /* tmp inode */
@@ -1715,26 +1739,28 @@ xfs_swap_extents(
                 goto out_unlock;
         }
 
-        error = filemap_write_and_wait(VFS_I(tip)->i_mapping);
+        error = xfs_swap_extent_flush(ip);
+        if (error)
+                goto out_unlock;
+        error = xfs_swap_extent_flush(tip);
         if (error)
                 goto out_unlock;
-        truncate_pagecache_range(VFS_I(tip), 0, -1);
-
-        xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
-        lock_flags |= XFS_ILOCK_EXCL;
 
-        /* Verify O_DIRECT for ftmp */
-        if (VFS_I(tip)->i_mapping->nrpages) {
-                error = -EINVAL;
+        tp = xfs_trans_alloc(mp, XFS_TRANS_SWAPEXT);
+        error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ichange, 0, 0);
+        if (error) {
+                xfs_trans_cancel(tp, 0);
                 goto out_unlock;
         }
+        xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
+        lock_flags |= XFS_ILOCK_EXCL;
 
         /* Verify all data are being swapped */
         if (sxp->sx_offset != 0 ||
             sxp->sx_length != ip->i_d.di_size ||
             sxp->sx_length != tip->i_d.di_size) {
                 error = -EFAULT;
-                goto out_unlock;
+                goto out_trans_cancel;
         }
 
         trace_xfs_swap_extent_before(ip, 0);
@@ -1746,7 +1772,7 @@ xfs_swap_extents(
                 xfs_notice(mp,
                     "%s: inode 0x%llx format is incompatible for exchanging.",
                                 __func__, ip->i_ino);
-                goto out_unlock;
+                goto out_trans_cancel;
         }
 
         /*
@@ -1761,41 +1787,8 @@ xfs_swap_extents(
             (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
             (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
                 error = -EBUSY;
-                goto out_unlock;
-        }
-
-        /* We need to fail if the file is memory mapped.  Once we have tossed
-         * all existing pages, the page fault will have no option
-         * but to go to the filesystem for pages. By making the page fault call
-         * vop_read (or write in the case of autogrow) they block on the iolock
-         * until we have switched the extents.
-         */
-        if (mapping_mapped(VFS_I(ip)->i_mapping)) {
-                error = -EBUSY;
-                goto out_unlock;
-        }
-
-        xfs_iunlock(ip, XFS_ILOCK_EXCL);
-        xfs_iunlock(tip, XFS_ILOCK_EXCL);
-        lock_flags &= ~XFS_ILOCK_EXCL;
-
-        /*
-         * There is a race condition here since we gave up the
-         * ilock.  However, the data fork will not change since
-         * we have the iolock (locked for truncation too) so we
-         * are safe.  We don't really care if non-io related
-         * fields change.
-         */
-        truncate_pagecache_range(VFS_I(ip), 0, -1);
-
-        tp = xfs_trans_alloc(mp, XFS_TRANS_SWAPEXT);
-        error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ichange, 0, 0);
-        if (error)
                 goto out_trans_cancel;
-
-        xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
-        lock_flags |= XFS_ILOCK_EXCL;
-
+        }
         /*
          * Count the number of extended attribute blocks
          */