ext4: fix reserved space counter leakage

stable inclusion
from stable-5.10.71
commit 9ccf35492b084ecbc916761a5c6f42599450f013
bugzilla: 182981 https://gitee.com/openeuler/kernel/issues/I4I3KD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9ccf35492b084ecbc916761a5c6f42599450f013

--------------------------------

commit 6fed8395 upstream.

When ext4_insert_delayed block receives and recovers from an error from
ext4_es_insert_delayed_block(), e.g., ENOMEM, it does not release the
space it has reserved for that block insertion as it should. One effect
of this bug is that s_dirtyclusters_counter is not decremented and
remains incorrectly elevated until the file system has been unmounted.
This can result in premature ENOSPC returns and apparent loss of free
space.

Another effect of this bug is that
/sys/fs/ext4/<dev>/delayed_allocation_blocks can remain non-zero even
after syncfs has been executed on the filesystem.

Besides, add check for s_dirtyclusters_counter when inode is going to be
evicted and freed. s_dirtyclusters_counter can still keep non-zero until
inode is written back in .evict_inode(), and thus the check is delayed
to .destroy_inode().

Fixes: 51865fda ("ext4: let ext4 maintain extent status tree")
Cc: stable@kernel.org
Suggested-by: NGao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: NJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210823061358.84473-1-jefflexu@linux.alibaba.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/ext4/inode.c

@@ -1628,6 +1628,7 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	int ret;
 	bool allocated = false;
+	bool reserved = false;
 
 	/*
 	 * If the cluster containing lblk is shared with a delayed,
@@ -1644,6 +1645,7 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
 		ret = ext4_da_reserve_space(inode);
 		if (ret != 0)   /* ENOSPC */
 			goto errout;
+		reserved = true;
 	} else {   /* bigalloc */
 		if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
 			if (!ext4_es_scan_clu(inode,
@@ -1656,6 +1658,7 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
 					ret = ext4_da_reserve_space(inode);
 					if (ret != 0)   /* ENOSPC */
 						goto errout;
+					reserved = true;
 				} else {
 					allocated = true;
 				}
@@ -1666,6 +1669,8 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
 	}
 
 	ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
+	if (ret && reserved)
+		ext4_da_release_space(inode, 1);
 
 errout:
 	return ret;

fs/ext4/super.c

@@ -1348,6 +1348,12 @@ static void ext4_destroy_inode(struct inode *inode)
 				true);
 		dump_stack();
 	}
+
+	if (EXT4_I(inode)->i_reserved_data_blocks)
+		ext4_msg(inode->i_sb, KERN_ERR,
+			 "Inode %lu (%p): i_reserved_data_blocks (%u) not cleared!",
+			 inode->i_ino, EXT4_I(inode),
+			 EXT4_I(inode)->i_reserved_data_blocks);
 }
 
 static void init_once(void *foo)