xfs: Convert double locking of MMAPLOCK to use VFS helpers

Convert places in XFS that take MMAPLOCK for two inodes to use helper
VFS provides for it (filemap_invalidate_down_write_two()). Note that
this changes lock ordering for MMAPLOCK from inode number based ordering
to pointer based ordering VFS generally uses.

CC: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 213a97a921bb9fa2b6f2e0cda0f526110ce1892f..1cd3f940fa6aedce0f2912b42fb7b5cc5914b082 100644 (file)
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1626,7 +1626,6 @@ xfs_swap_extents(
        struct xfs_bstat        *sbp = &sxp->sx_stat;
        int                     src_log_flags, target_log_flags;
        int                     error = 0;
-       int                     lock_flags;
        uint64_t                f;
        int                     resblks = 0;
        unsigned int            flags = 0;
@@ -1638,8 +1637,8 @@ xfs_swap_extents(
         * do the rest of the checks.
         */
        lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
-       lock_flags = XFS_MMAPLOCK_EXCL;
-       xfs_lock_two_inodes(ip, XFS_MMAPLOCK_EXCL, tip, XFS_MMAPLOCK_EXCL);
+       filemap_invalidate_lock_two(VFS_I(ip)->i_mapping,
+                                   VFS_I(tip)->i_mapping);
 
        /* Verify that both files have the same format */
        if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
@@ -1711,7 +1710,6 @@ xfs_swap_extents(
         * or cancel will unlock the inodes from this point onwards.
         */
        xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
-       lock_flags |= XFS_ILOCK_EXCL;
        xfs_trans_ijoin(tp, ip, 0);
        xfs_trans_ijoin(tp, tip, 0);
 
@@ -1830,13 +1828,16 @@ xfs_swap_extents(
        trace_xfs_swap_extent_after(ip, 0);
        trace_xfs_swap_extent_after(tip, 1);
 
+out_unlock_ilock:
+       xfs_iunlock(ip, XFS_ILOCK_EXCL);
+       xfs_iunlock(tip, XFS_ILOCK_EXCL);
 out_unlock:
-       xfs_iunlock(ip, lock_flags);
-       xfs_iunlock(tip, lock_flags);
+       filemap_invalidate_unlock_two(VFS_I(ip)->i_mapping,
+                                     VFS_I(tip)->i_mapping);
        unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));
        return error;
 
 out_trans_cancel:
        xfs_trans_cancel(tp);
-       goto out_unlock;
+       goto out_unlock_ilock;
 }

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index d6a8ac76b45d060f5623c05691b49318e183eea0..3c0bb21453dc7a0a4dceecb8f095811b8da4f5c0 100644 (file)
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -552,12 +552,10 @@ again:
 }
 
 /*
- * xfs_lock_two_inodes() can only be used to lock one type of lock at a time -
- * the mmaplock or the ilock, but not more than one type at a time. If we lock
- * more than one at a time, lockdep will report false positives saying we have
- * violated locking orders.  The iolock must be double-locked separately since
- * we use i_rwsem for that.  We now support taking one lock EXCL and the other
- * SHARED.
+ * xfs_lock_two_inodes() can only be used to lock ilock. The iolock and
+ * mmaplock must be double-locked separately since we use i_rwsem and
+ * invalidate_lock for that. We now support taking one lock EXCL and the
+ * other SHARED.
  */
 void
 xfs_lock_two_inodes(
@@ -575,15 +573,8 @@ xfs_lock_two_inodes(
        ASSERT(hweight32(ip1_mode) == 1);
        ASSERT(!(ip0_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
        ASSERT(!(ip1_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
-       ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
-              !(ip0_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
-       ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
-              !(ip1_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
-       ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
-              !(ip0_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
-       ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
-              !(ip1_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
-
+       ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));
+       ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)));
        ASSERT(ip0->i_ino != ip1->i_ino);
 
        if (ip0->i_ino > ip1->i_ino) {
@@ -3748,11 +3739,8 @@ xfs_ilock2_io_mmap(
        ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2));
        if (ret)
                return ret;
-       if (ip1 == ip2)
-               xfs_ilock(ip1, XFS_MMAPLOCK_EXCL);
-       else
-               xfs_lock_two_inodes(ip1, XFS_MMAPLOCK_EXCL,
-                                   ip2, XFS_MMAPLOCK_EXCL);
+       filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,
+                                   VFS_I(ip2)->i_mapping);
        return 0;
 }
 
@@ -3762,12 +3750,9 @@ xfs_iunlock2_io_mmap(
        struct xfs_inode        *ip1,
        struct xfs_inode        *ip2)
 {
-       bool                    same_inode = (ip1 == ip2);
-
-       xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);
-       if (!same_inode)
-               xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
+       filemap_invalidate_unlock_two(VFS_I(ip1)->i_mapping,
+                                     VFS_I(ip2)->i_mapping);
        inode_unlock(VFS_I(ip2));
-       if (!same_inode)
+       if (ip1 != ip2)
                inode_unlock(VFS_I(ip1));
 }