From 6fed83957f21eff11c8496e9f24253b03d2bc1dc Mon Sep 17 00:00:00 2001

From: Jeffle Xu <jefflexu@linux.alibaba.com>

Date: Mon, 23 Aug 2021 14:13:58 +0800

Subject: [PATCH] ext4: fix reserved space counter leakage

Git-commit: 6fed83957f21eff11c8496e9f24253b03d2bc1dc

Patch-mainline: v5.15-rc4

References: bsc#1191450

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: 51865fda28e5 ("ext4: let ext4 maintain extent status tree")

Cc: stable@kernel.org

Suggested-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>

Reviewed-by: Eric Whitney <enwlinux@gmail.com>

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Link: https://lore.kernel.org/r/20210823061358.84473-1-jefflexu@linux.alibaba.com

Acked-by: Jan Kara <jack@suse.cz>

---

 fs/ext4/inode.c | 5 +++++

 fs/ext4/super.c | 6 ++++++

 2 files changed, 11 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c

index 2a076d236ba1..9df1ab070fa5 100644

--- a/fs/ext4/inode.c

+++ b/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;

diff --git a/fs/ext4/super.c b/fs/ext4/super.c

index feca816b6bf3..a52f1572daa5 100644

--- a/fs/ext4/super.c

+++ b/fs/ext4/super.c

@@ -1352,6 +1352,12 @@ 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)

-- 

2.26.2