Commit 347fa6f1 authored by Akira Fujita's avatar Akira Fujita Committed by Theodore Ts'o
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ext4: Add null extent check to ext_get_path 



There is the possibility that path structure which is taken
by ext4_ext_find_extent() indicates null extents.
Because during data block exchanging in ext4_move_extents(),
constitution of an extent tree may be changed.
As a solution, the patch adds null extent check
to ext_get_path().

Reported-by: default avatarPeng Tao <bergwolf@gmail.com>
Signed-off-by: default avatarAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 2147b1a6

fs/ext4/move_extent.c

+16 −18
Original line number Diff line number Diff line
@@ -39,7 +39,9 @@ get_ext_path(struct inode *inode, ext4_lblk_t lblock, 
	if (IS_ERR(*path)) {

		ret = PTR_ERR(*path);

		*path = NULL;

	}

	} else if ((*path)[ext_depth(inode)].p_ext == NULL)

		ret = -ENODATA;



	return ret;

}
@@ -316,7 +318,7 @@ mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode, 


	if (new_flag) {

		err = get_ext_path(orig_inode, eblock, &orig_path);

		if (orig_path == NULL)

		if (err)

			goto out;



		if (ext4_ext_insert_extent(handle, orig_inode,
@@ -327,7 +329,7 @@ mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode, 
	if (end_flag) {

		err = get_ext_path(orig_inode,

				le32_to_cpu(end_ext->ee_block) - 1, &orig_path);

		if (orig_path == NULL)

		if (err)

			goto out;



		if (ext4_ext_insert_extent(handle, orig_inode,
@@ -673,12 +675,12 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode, 


	/* Get the original extent for the block "orig_off" */

	err = get_ext_path(orig_inode, orig_off, &orig_path);

	if (orig_path == NULL)

	if (err)

		goto out;



	/* Get the donor extent for the head */

	err = get_ext_path(donor_inode, donor_off, &donor_path);

	if (donor_path == NULL)

	if (err)

		goto out;

	depth = ext_depth(orig_inode);

	oext = orig_path[depth].p_ext;
@@ -733,7 +735,7 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode, 
		if (orig_path)

			ext4_ext_drop_refs(orig_path);

		err = get_ext_path(orig_inode, orig_off, &orig_path);

		if (orig_path == NULL)

		if (err)

			goto out;

		depth = ext_depth(orig_inode);

		oext = orig_path[depth].p_ext;
@@ -747,7 +749,7 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode, 
		if (donor_path)

			ext4_ext_drop_refs(donor_path);

		err = get_ext_path(donor_inode, donor_off, &donor_path);

		if (donor_path == NULL)

		if (err)

			goto out;

		depth = ext_depth(donor_inode);

		dext = donor_path[depth].p_ext;
@@ -1221,7 +1223,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, 
					donor_start, &len, *moved_len);

	mext_double_up_read(orig_inode, donor_inode);

	if (ret1)

		goto out2;

		goto out;



	file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits;

	block_end = block_start + len - 1;
@@ -1229,20 +1231,16 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, 
		len -= block_end - file_end;



	ret1 = get_ext_path(orig_inode, block_start, &orig_path);

	if (orig_path == NULL)

		goto out2;

	if (ret1)

		goto out;



	/* Get path structure to check the hole */

	ret1 = get_ext_path(orig_inode, block_start, &holecheck_path);

	if (holecheck_path == NULL)

	if (ret1)

		goto out;



	depth = ext_depth(orig_inode);

	ext_cur = holecheck_path[depth].p_ext;

	if (ext_cur == NULL) {

		ret1 = -EINVAL;

		goto out;

	}



	/*

	 * Get proper extent whose ee_block is beyond block_start
@@ -1371,7 +1369,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, 
		if (holecheck_path)

			ext4_ext_drop_refs(holecheck_path);

		ret1 = get_ext_path(orig_inode, seq_start, &holecheck_path);

		if (holecheck_path == NULL)

		if (ret1)

			break;

		depth = holecheck_path->p_depth;
@@ -1379,7 +1377,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, 
		if (orig_path)

			ext4_ext_drop_refs(orig_path);

		ret1 = get_ext_path(orig_inode, seq_start, &orig_path);

		if (orig_path == NULL)

		if (ret1)

			break;



		ext_cur = holecheck_path[depth].p_ext;
@@ -1396,7 +1394,7 @@ out: 
		ext4_ext_drop_refs(holecheck_path);

		kfree(holecheck_path);

	}

out2:



	ret2 = mext_inode_double_unlock(orig_inode, donor_inode);



	if (ret1)

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