From: Zhang Yi yi.zhang@huawei.com
[ Upstream commit 15baa7dcadf1c4f0b4f752dc054191855ff2d78e ]
We have already check the io_error and uptodate flag before submitting the superblock buffer, and re-set the uptodate flag if it has been failed to write out. But it was lockless and could be raced by another ext4_commit_super(), and finally trigger '!uptodate' WARNING when marking buffer dirty. Fix it by submit buffer directly.
Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Jan Kara jack@suse.cz Reviewed-by: Ritesh Harjani ritesh.list@gmail.com Link: https://lore.kernel.org/r/20220520023216.3065073-1-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/super.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 3e6e618019a2..5da37cbe1176 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -6006,7 +6006,6 @@ static void ext4_update_super(struct super_block *sb) static int ext4_commit_super(struct super_block *sb) { struct buffer_head *sbh = EXT4_SB(sb)->s_sbh; - int error = 0;
if (!sbh) return -EINVAL; @@ -6015,6 +6014,13 @@ static int ext4_commit_super(struct super_block *sb)
ext4_update_super(sb);
+ lock_buffer(sbh); + /* Buffer got discarded which means block device got invalidated */ + if (!buffer_mapped(sbh)) { + unlock_buffer(sbh); + return -EIO; + } + if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) { /* * Oh, dear. A previous attempt to write the @@ -6029,17 +6035,21 @@ static int ext4_commit_super(struct super_block *sb) clear_buffer_write_io_error(sbh); set_buffer_uptodate(sbh); } - BUFFER_TRACE(sbh, "marking dirty"); - mark_buffer_dirty(sbh); - error = __sync_dirty_buffer(sbh, - REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0)); + get_bh(sbh); + /* Clear potential dirty bit if it was journalled update */ + clear_buffer_dirty(sbh); + sbh->b_end_io = end_buffer_write_sync; + submit_bh(REQ_OP_WRITE, + REQ_SYNC | (test_opt(sb, BARRIER) ? REQ_FUA : 0), sbh); + wait_on_buffer(sbh); if (buffer_write_io_error(sbh)) { ext4_msg(sb, KERN_ERR, "I/O error while writing " "superblock"); clear_buffer_write_io_error(sbh); set_buffer_uptodate(sbh); + return -EIO; } - return error; + return 0; }
/*