[34/90] ext4: Add null extent check to ext_get_path

Greg KH
2009-12-11T04:36:55Z

[-- Attachment #1: 0034-ext4-Add-null-extent-check-to-ext_get_path.patch --]
[-- Type: text/plain, Size: 4215 bytes --]

2.6.31-stable review patch. If anyone has any objections, please let us know.

------------------
(cherry picked from commit 347fa6f1c7cb5df2b38d3c9167cfe242ce0cd1da)

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: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/ext4/move_extent.c | 34 ++++++++++++++++------------------
1 file changed, 16 insertions(+), 18 deletions(-)

--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -39,7 +39,9 @@ get_ext_path(struct inode *inode, ext4_l
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 *hand

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 *hand
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,

/* 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,
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,
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, s
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, s
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, s
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, s
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)