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Subject[PATCH 5.15 005/128] ext4: check for inconsistent extents between index and leaf block
Date
From: Zhang Yi <yi.zhang@huawei.com>

commit 9c6e071913792d80894cd0be98cc3c4b770e26d3 upstream.

Now that we can check out overlapping extents in leaf block and
out-of-order index extents in index block. But the .ee_block in the
first extent of one leaf block should equal to the .ei_block in it's
parent index extent entry. This patch add a check to verify such
inconsistent between the index and leaf block.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210908120850.4012324-3-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ext4/extents.c | 59 ++++++++++++++++++++++++++++++++----------------------
1 file changed, 36 insertions(+), 23 deletions(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -367,7 +367,8 @@ static int ext4_valid_extent_idx(struct

static int ext4_valid_extent_entries(struct inode *inode,
struct ext4_extent_header *eh,
- ext4_fsblk_t *pblk, int depth)
+ ext4_lblk_t lblk, ext4_fsblk_t *pblk,
+ int depth)
{
unsigned short entries;
ext4_lblk_t lblock = 0;
@@ -381,6 +382,14 @@ static int ext4_valid_extent_entries(str
if (depth == 0) {
/* leaf entries */
struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
+
+ /*
+ * The logical block in the first entry should equal to
+ * the number in the index block.
+ */
+ if (depth != ext_depth(inode) &&
+ lblk != le32_to_cpu(ext->ee_block))
+ return 0;
while (entries) {
if (!ext4_valid_extent(inode, ext))
return 0;
@@ -397,6 +406,14 @@ static int ext4_valid_extent_entries(str
}
} else {
struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
+
+ /*
+ * The logical block in the first entry should equal to
+ * the number in the parent index block.
+ */
+ if (depth != ext_depth(inode) &&
+ lblk != le32_to_cpu(ext_idx->ei_block))
+ return 0;
while (entries) {
if (!ext4_valid_extent_idx(inode, ext_idx))
return 0;
@@ -417,7 +434,7 @@ static int ext4_valid_extent_entries(str

static int __ext4_ext_check(const char *function, unsigned int line,
struct inode *inode, struct ext4_extent_header *eh,
- int depth, ext4_fsblk_t pblk)
+ int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk)
{
const char *error_msg;
int max = 0, err = -EFSCORRUPTED;
@@ -443,7 +460,7 @@ static int __ext4_ext_check(const char *
error_msg = "invalid eh_entries";
goto corrupted;
}
- if (!ext4_valid_extent_entries(inode, eh, &pblk, depth)) {
+ if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) {
error_msg = "invalid extent entries";
goto corrupted;
}
@@ -473,7 +490,7 @@ corrupted:
}

#define ext4_ext_check(inode, eh, depth, pblk) \
- __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
+ __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk), 0)

int ext4_ext_check_inode(struct inode *inode)
{
@@ -506,16 +523,18 @@ static void ext4_cache_extents(struct in

static struct buffer_head *
__read_extent_tree_block(const char *function, unsigned int line,
- struct inode *inode, ext4_fsblk_t pblk, int depth,
- int flags)
+ struct inode *inode, struct ext4_extent_idx *idx,
+ int depth, int flags)
{
struct buffer_head *bh;
int err;
gfp_t gfp_flags = __GFP_MOVABLE | GFP_NOFS;
+ ext4_fsblk_t pblk;

if (flags & EXT4_EX_NOFAIL)
gfp_flags |= __GFP_NOFAIL;

+ pblk = ext4_idx_pblock(idx);
bh = sb_getblk_gfp(inode->i_sb, pblk, gfp_flags);
if (unlikely(!bh))
return ERR_PTR(-ENOMEM);
@@ -528,8 +547,8 @@ __read_extent_tree_block(const char *fun
}
if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
return bh;
- err = __ext4_ext_check(function, line, inode,
- ext_block_hdr(bh), depth, pblk);
+ err = __ext4_ext_check(function, line, inode, ext_block_hdr(bh),
+ depth, pblk, le32_to_cpu(idx->ei_block));
if (err)
goto errout;
set_buffer_verified(bh);
@@ -547,8 +566,8 @@ errout:

}

-#define read_extent_tree_block(inode, pblk, depth, flags) \
- __read_extent_tree_block(__func__, __LINE__, (inode), (pblk), \
+#define read_extent_tree_block(inode, idx, depth, flags) \
+ __read_extent_tree_block(__func__, __LINE__, (inode), (idx), \
(depth), (flags))

/*
@@ -598,8 +617,7 @@ int ext4_ext_precache(struct inode *inod
i--;
continue;
}
- bh = read_extent_tree_block(inode,
- ext4_idx_pblock(path[i].p_idx++),
+ bh = read_extent_tree_block(inode, path[i].p_idx++,
depth - i - 1,
EXT4_EX_FORCE_CACHE);
if (IS_ERR(bh)) {
@@ -904,8 +922,7 @@ ext4_find_extent(struct inode *inode, ex
path[ppos].p_depth = i;
path[ppos].p_ext = NULL;

- bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
- flags);
+ bh = read_extent_tree_block(inode, path[ppos].p_idx, --i, flags);
if (IS_ERR(bh)) {
ret = PTR_ERR(bh);
goto err;
@@ -1514,7 +1531,6 @@ static int ext4_ext_search_right(struct
struct ext4_extent_header *eh;
struct ext4_extent_idx *ix;
struct ext4_extent *ex;
- ext4_fsblk_t block;
int depth; /* Note, NOT eh_depth; depth from top of tree */
int ee_len;

@@ -1581,20 +1597,17 @@ got_index:
* follow it and find the closest allocated
* block to the right */
ix++;
- block = ext4_idx_pblock(ix);
while (++depth < path->p_depth) {
/* subtract from p_depth to get proper eh_depth */
- bh = read_extent_tree_block(inode, block,
- path->p_depth - depth, 0);
+ bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
if (IS_ERR(bh))
return PTR_ERR(bh);
eh = ext_block_hdr(bh);
ix = EXT_FIRST_INDEX(eh);
- block = ext4_idx_pblock(ix);
put_bh(bh);
}

- bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
+ bh = read_extent_tree_block(inode, ix, path->p_depth - depth, 0);
if (IS_ERR(bh))
return PTR_ERR(bh);
eh = ext_block_hdr(bh);
@@ -2973,9 +2986,9 @@ again:
ext_debug(inode, "move to level %d (block %llu)\n",
i + 1, ext4_idx_pblock(path[i].p_idx));
memset(path + i + 1, 0, sizeof(*path));
- bh = read_extent_tree_block(inode,
- ext4_idx_pblock(path[i].p_idx), depth - i - 1,
- EXT4_EX_NOCACHE);
+ bh = read_extent_tree_block(inode, path[i].p_idx,
+ depth - i - 1,
+ EXT4_EX_NOCACHE);
if (IS_ERR(bh)) {
/* should we reset i_size? */
err = PTR_ERR(bh);

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