From cf37e972478ec58a8a54a6b4f951815f0ae28f78 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 8 Jun 2010 18:14:51 +0200 Subject: [PATCH] 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 Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 6 ++++++ fs/ubifs/budget.c | 2 ++ 2 files changed, 8 insertions(+) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 759666966c6d..2627f0dfcd9c 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -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); } diff --git a/fs/ubifs/budget.c b/fs/ubifs/budget.c index 076ca50e9933..c8ff0d1ae5d3 100644 --- a/fs/ubifs/budget.c +++ b/fs/ubifs/budget.c @@ -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); } /** -- 2.34.1