writeback: enforce s_umount locking in writeback_inodes_sb

Make sure that not only sync_filesystem but all callers of writeback_inodes_sb
have the superblock protected against remount.  As-is this disables all
functionality for these callers, but the next patch relies on this locking to
fix writeback_inodes_sb for sync_filesystem.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Christoph Hellwig 2010-06-08 18:14:51 +02:00 committed by Jens Axboe
parent 3c4d716538
commit cf37e97247
2 changed files with 8 additions and 0 deletions

View File

@ -1180,6 +1180,8 @@ void writeback_inodes_sb(struct super_block *sb)
.sync_mode = WB_SYNC_NONE,
};
WARN_ON(!rwsem_is_locked(&sb->s_umount));
args.nr_pages = nr_dirty + nr_unstable +
(inodes_stat.nr_inodes - inodes_stat.nr_unused);
@ -1197,7 +1199,9 @@ EXPORT_SYMBOL(writeback_inodes_sb);
int writeback_inodes_sb_if_idle(struct super_block *sb)
{
if (!writeback_in_progress(sb->s_bdi)) {
down_read(&sb->s_umount);
writeback_inodes_sb(sb);
up_read(&sb->s_umount);
return 1;
} else
return 0;
@ -1220,6 +1224,8 @@ void sync_inodes_sb(struct super_block *sb)
.range_cyclic = 0,
};
WARN_ON(!rwsem_is_locked(&sb->s_umount));
bdi_queue_work_onstack(&args);
wait_sb_inodes(sb);
}

View File

@ -62,7 +62,9 @@
*/
static void shrink_liability(struct ubifs_info *c, int nr_to_write)
{
down_read(&c->vfs_sb->s_umount);
writeback_inodes_sb(c->vfs_sb);
up_read(&c->vfs_sb->s_umount);
}
/**