linux-ext4 - [PATCH 2/2] ext4: Avoid unaccounted block allocation when expanding inode

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Date:   Wed,  7 Dec 2022 12:59:28 +0100
From:   Jan Kara <jack@...e.cz>
To:     Ted Tso <tytso@....edu>
Cc:     <linux-ext4@...r.kernel.org>, Pengfei Xu <pengfei.xu@...el.com>,
        Jan Kara <jack@...e.cz>
Subject: [PATCH 2/2] ext4: Avoid unaccounted block allocation when expanding inode

When expanding inode space in ext4_expand_extra_isize_ea() we may need
to allocate external xattr block. If quota is not initialized for the
inode, the block allocation will not be accounted into quota usage. Make
sure the quota is initialized before we try to expand inode space.

Reported-by: Pengfei Xu <pengfei.xu@...el.com>
Link: https://lore.kernel.org/all/Y5BT+k6xWqthZc1P@xpf.sh.intel.com
Signed-off-by: Jan Kara <jack@...e.cz>
---
 fs/ext4/inode.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2b5ef1b64249..62c81af57bb0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5853,6 +5853,14 @@ static int __ext4_expand_extra_isize(struct inode *inode,
 		return 0;
 	}
 
+	/*
+	 * We may need to allocate external xattr block so we need quotas
+	 * initialized. Here we can be called with various locks held so we
+	 * cannot affort to initialize quotas ourselves. So just bail.
+	 */
+	if (dquot_initialize_needed(inode))
+		return -EAGAIN;
+
 	/* try to expand with EAs present */
 	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
 					   raw_inode, handle);
-- 
2.35.3