xfs: Convert to new freezing code

Generic code now blocks all writers from standard write paths. So we add
blocking of all writers coming from ioctl (we get a protection of ioctl against
racing remount read-only as a bonus) and convert xfs_file_aio_write() to a
non-racy freeze protection. We also keep freeze protection on transaction
start to block internal filesystem writes such as removal of preallocated
blocks.

CC: Ben Myers <bpm@sgi.com>
CC: Alex Elder <elder@kernel.org>
CC: xfs@oss.sgi.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 18 insertions, 0 deletions

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 8dad722c004..daa42383ebd 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -124,6 +124,12 @@ xfs_setfilesize_trans_alloc(
         ioend->io_append_trans = tp;
 
         /*
+         * We will pass freeze protection with a transaction.  So tell lockdep
+         * we released it.
+         */
+        rwsem_release(&ioend->io_inode->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
+                      1, _THIS_IP_);
+        /*
          * We hand off the transaction to the completion thread now, so
          * clear the flag here.
          */
@@ -199,6 +205,15 @@ xfs_end_io(
         struct xfs_inode *ip = XFS_I(ioend->io_inode);
         int             error = 0;
 
+        if (ioend->io_append_trans) {
+                /*
+                 * We've got freeze protection passed with the transaction.
+                 * Tell lockdep about it.
+                 */
+                rwsem_acquire_read(
+                        &ioend->io_inode->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
+                        0, 1, _THIS_IP_);
+        }
         if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
                 ioend->io_error = -EIO;
                 goto done;
@@ -1410,6 +1425,9 @@ out_trans_cancel:
         if (ioend->io_append_trans) {
                 current_set_flags_nested(&ioend->io_append_trans->t_pflags,
                                          PF_FSTRANS);
+                rwsem_acquire_read(
+                        &inode->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
+                        0, 1, _THIS_IP_);
                 xfs_trans_cancel(ioend->io_append_trans, 0);
         }
 out_destroy_ioend: