ext4: move 'ix' sanity check to corrent position

[ Upstream commit af90a8f4a09ec4a3de20142e37f37205d4687f28 ]

Check 'ix' before it is used.

Fixes: 80e675f906db ("ext4: optimize memmmove lengths in extent/index insertions")
Signed-off-by: Gou Hao <gouhao@uniontech.com>
Link: https://lore.kernel.org/r/20230906013341.7199-1-gouhao@uniontech.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 202c769..4d8496d 100644 (file)
--- 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);