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From:   gouhao@uniontech.com
To:     tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org
Cc:     egouriou@google.com, linux-kernel@vger.kernel.org
Subject: [PATCH] ext4: move 'ix' sanity check to corrent position
Date:   Wed,  6 Sep 2023 09:33:41 +0800
Message-Id: <20230906013341.7199-1-gouhao@uniontech.com>
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From: Gou Hao <gouhao@uniontech.com>

'ix' check should be before using it.

Fixes: 80e675f906db ("ext4: optimize memmmove lengths in extent/index insertions")
Signed-off-by: Gou Hao <gouhao@uniontech.com>
---
 fs/ext4/extents.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 202c76996b62..4d8496d1a8ac 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1010,6 +1010,11 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 		ix = curp->p_idx;
 	}
 
+	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
+		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
+		return -EFSCORRUPTED;
+	}
+
 	len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 	BUG_ON(len < 0);
 	if (len > 0) {
@@ -1019,11 +1024,6 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 		memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 	}
 
-	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
-		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
-		return -EFSCORRUPTED;
-	}
-
 	ix->ei_block = cpu_to_le32(logical);
 	ext4_idx_store_pblock(ix, ptr);
 	le16_add_cpu(&curp->p_hdr->eh_entries, 1);
-- 
2.20.1