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| author | Robin Dong <hao.bigrat@gmail.com> | 2011-07-17 23:43:42 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-07-17 23:43:42 -0400 |
| commit | d46203159ed376fdbe2b05aa57e58207bf27a8f9 (patch) | |
| tree | 8bcbe5545066606b12d6cd250747471802520c0b | |
| parent | 015861badd0db43d025bbb538f8fc62dfaf3f18d (diff) | |
| download | blackbird-op-linux-d46203159ed376fdbe2b05aa57e58207bf27a8f9.tar.gz blackbird-op-linux-d46203159ed376fdbe2b05aa57e58207bf27a8f9.zip | |
ext4: avoid eh_entries overflow before insert extent_idx
If eh_entries is equal to (or greater than) eh_max, the operation of
inserting new extent_idx will make number of entries overflow.
So check eh_entries before inserting the new extent_idx.
Although there is no bug case according the code (function
ext4_ext_insert_index is called by ext4_ext_split and ext4_ext_split
is called only if the index block has free space), the right logic
should be "lookup the capacity before insertion".
Signed-off-by: Robin Dong <sanbai@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/extents.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index b8acfab00224..9bec432e2d26 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -741,6 +741,16 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, logical, le32_to_cpu(curp->p_idx->ei_block)); return -EIO; } + + if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) + >= le16_to_cpu(curp->p_hdr->eh_max))) { + EXT4_ERROR_INODE(inode, + "eh_entries %d >= eh_max %d!", + le16_to_cpu(curp->p_hdr->eh_entries), + le16_to_cpu(curp->p_hdr->eh_max)); + return -EIO; + } + len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; if (logical > le32_to_cpu(curp->p_idx->ei_block)) { /* insert after */ @@ -770,14 +780,6 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, ext4_idx_store_pblock(ix, ptr); le16_add_cpu(&curp->p_hdr->eh_entries, 1); - if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) - > le16_to_cpu(curp->p_hdr->eh_max))) { - EXT4_ERROR_INODE(inode, - "eh_entries %d > eh_max %d!", - le16_to_cpu(curp->p_hdr->eh_entries), - le16_to_cpu(curp->p_hdr->eh_max)); - return -EIO; - } if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) { EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!"); return -EIO; |
