Commit 9c6e0719 authored by Zhang Yi's avatar Zhang Yi Committed by Theodore Ts'o
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ext4: check for inconsistent extents between index and leaf block 



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: default avatarZhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210908120850.4012324-3-yi.zhang@huawei.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 8dd27fec

fs/ext4/extents.c

+36 −23
Original line number Diff line number Diff line
@@ -354,7 +354,8 @@ static int ext4_valid_extent_idx(struct inode *inode, 


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;
@@ -368,6 +369,14 @@ static int ext4_valid_extent_entries(struct inode *inode, 
	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;
@@ -384,6 +393,14 @@ static int ext4_valid_extent_entries(struct inode *inode, 
		}

	} 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;
@@ -404,7 +421,7 @@ static int ext4_valid_extent_entries(struct inode *inode, 


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;
@@ -430,7 +447,7 @@ static int __ext4_ext_check(const char *function, unsigned int line, 
		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;

	}
@@ -460,7 +477,7 @@ static int __ext4_ext_check(const char *function, unsigned int line, 
}



#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)

{
@@ -493,16 +510,18 @@ static void ext4_cache_extents(struct inode *inode, 


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);
@@ -515,8 +534,8 @@ __read_extent_tree_block(const char *function, unsigned int line, 
	}

	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);
@@ -534,8 +553,8 @@ __read_extent_tree_block(const char *function, unsigned int line, 


}



#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))



/*
@@ -585,8 +604,7 @@ int ext4_ext_precache(struct inode *inode) 
			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)) {
@@ -893,8 +911,7 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block, 
		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;
@@ -1503,7 +1520,6 @@ static int ext4_ext_search_right(struct inode *inode, 
	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;
@@ -1570,20 +1586,17 @@ static int ext4_ext_search_right(struct inode *inode, 
	 * 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);
@@ -2962,8 +2975,8 @@ int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, 
			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,

			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? */