[PATCH] ext4: do less extent validations

[PATCH] ext4: do less extent validations

[Thiemo Nagel]

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Based on 2.6.29-rc7 with Aneesh Kumar's patches:
ext4: Validate extent details only when read from the disk
ext4: Add checks to validate extent entries

Sets need_to_validate=0 inside instead of outside the loop.

Signed-off-by: Thiemo Nagel <thiemo.nagel@ph.tum.de>

[-- Attachment #2: less-extent-validations.patch --]
[-- Type: text/x-patch, Size: 618 bytes --]

--- linux-2.6.29-rc7/fs/ext4/extents.c~	2009-03-12 14:51:21.000000000 +0100
+++ linux-2.6.29-rc7/fs/ext4/extents.c	2009-03-12 16:23:41.000000000 +0100
@@ -607,7 +607,6 @@
 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 					struct ext4_ext_path *path)
 {
-	int need_to_validate = 0;
 	struct ext4_extent_header *eh;
 	struct buffer_head *bh;
 	short int depth, i, ppos = 0, alloc = 0;
@@ -629,6 +628,7 @@
 	i = depth;
 	/* walk through the tree */
 	while (i) {
+		int need_to_validate = 0;
 		ext_debug("depth %d: num %d, max %d\n",
 			  ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 

Re: [PATCH] ext4: do less extent validations

[Thiemo Nagel]

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Thiemo Nagel wrote:
> 
> Based on 2.6.29-rc7 with Aneesh Kumar's patches:
> ext4: Validate extent details only when read from the disk
> ext4: Add checks to validate extent entries
> 
> Sets need_to_validate=0 inside instead of outside the loop.

OTOH, why not remove the variable altogether?  (cf. attached patch)

Kind regards,

Signed-off-by: Thiemo Nagel <thiemo.nagel@ph.tum.de>

-- 
+-----------------------------------+--------------------------+
| Dipl.-Phys. Thiemo Nagel          |                          |
| Technische Universitaet Muenchen  | Room    PH1 3276         |
| Physik-Department E18             |                          |
| James-Franck-Strasse              | Phone  +49 89 289-12379  |
| D-85747 Garching                  | Fax    +49 89 289-12570  |
+-----------------------------------+--------------------------+


[-- Attachment #2: less-extent-validations.patch2 --]
[-- Type: text/plain, Size: 688 bytes --]

--- linux-2.6.29-rc8/fs/ext4/extents.c~	2009-03-16 19:37:22.000000000 +0100
+++ linux-2.6.29-rc8/fs/ext4/extents.c	2009-03-16 19:50:33.000000000 +0100
@@ -607,7 +607,6 @@
 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 					struct ext4_ext_path *path)
 {
-	int need_to_validate = 0;
 	struct ext4_extent_header *eh;
 	struct buffer_head *bh;
 	short int depth, i, ppos = 0, alloc = 0;
@@ -646,17 +645,16 @@
 				goto err;
 			}
 			/* validate the extent entries */
-			need_to_validate = 1;
+			if (ext4_ext_check(inode, eh, i))
+				goto err;
 		}
+
 		eh = ext_block_hdr(bh);
 		ppos++;
 		BUG_ON(ppos > depth);
 		path[ppos].p_bh = bh;
 		path[ppos].p_hdr = eh;
 		i--;

Re: [PATCH] ext4: do less extent validations

[Theodore Tso]

On Thu, Mar 12, 2009 at 04:32:54PM +0100, Thiemo Nagel wrote:
>
> Based on 2.6.29-rc7 with Aneesh Kumar's patches:
> ext4: Validate extent details only when read from the disk
> ext4: Add checks to validate extent entries
>
> Sets need_to_validate=0 inside instead of outside the loop.

I've integrated this change into Aneesh's patch in the ext4 patch
queue.

					- Ted

Re: [PATCH] ext4: do less extent validations

[Theodore Tso]

On Mon, Mar 16, 2009 at 08:05:30PM +0100, Thiemo Nagel wrote:
> Thiemo Nagel wrote:
>>
>> Based on 2.6.29-rc7 with Aneesh Kumar's patches:
>> ext4: Validate extent details only when read from the disk
>> ext4: Add checks to validate extent entries
>>
>> Sets need_to_validate=0 inside instead of outside the loop.
>
> OTOH, why not remove the variable altogether?  (cf. attached patch)

This patch causes ext4_ext_check to be called before the variables eh
is set, and before variable is updated.

					- Ted