* [PATCH] ext4: page_cache pages over pinned in ext4_mb_free_metadata()
@ 2010-03-24 13:00 jing zhang
2010-03-24 17:16 ` Aneesh Kumar K. V
0 siblings, 1 reply; 3+ messages in thread
From: jing zhang @ 2010-03-24 13:00 UTC (permalink / raw)
To: linux-ext4; +Cc: Theodore Ts'o, Andreas Dilger, Dave Kleikamp
From: Jing Zhang <zj.barak@gmail.com>
Date: Wed Mar 24 20:38:48 2010
The function, ext4_mb_free_metadata(), is called after
ext4_mb_load_buddy(sb, block_group, &e4b);
and before
ext4_mb_release_desc(&e4b);
in the function, ext4_mb_free_blocks(), so the bd_bitmap_page and
bd_buddy_page of e4b are well managed.
If for special purpose, page_cache_get() is issued on these two pages,
there should also be page_cache_release() issued correspondingly, or
the two pages are over pinned.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Jing Zhang <zj.barak@gmail.com>
---
--- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
+++ ext4_mm_leak/mballoc6.c 2010-03-24 20:31:52.000000000 +0800
@@ -4361,15 +4361,6 @@ ext4_mb_free_metadata(handle_t *handle,
new_node = &new_entry->node;
block = new_entry->start_blk;
- if (!*n) {
- /* first free block exent. We need to
- protect buddy cache from being freed,
- * otherwise we'll refresh it from
- * on-disk bitmap and lose not-yet-available
- * blocks */
- page_cache_get(e4b->bd_buddy_page);
- page_cache_get(e4b->bd_bitmap_page);
- }
while (*n) {
parent = *n;
entry = rb_entry(parent, struct ext4_free_data, node);
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] ext4: page_cache pages over pinned in ext4_mb_free_metadata()
2010-03-24 13:00 [PATCH] ext4: page_cache pages over pinned in ext4_mb_free_metadata() jing zhang
@ 2010-03-24 17:16 ` Aneesh Kumar K. V
2010-03-25 14:23 ` jing zhang
0 siblings, 1 reply; 3+ messages in thread
From: Aneesh Kumar K. V @ 2010-03-24 17:16 UTC (permalink / raw)
To: jing zhang, linux-ext4; +Cc: Theodore Ts'o, Andreas Dilger, Dave Kleikamp
On Wed, 24 Mar 2010 21:00:34 +0800, jing zhang <zj.barak@gmail.com> wrote:
> From: Jing Zhang <zj.barak@gmail.com>
>
> Date: Wed Mar 24 20:38:48 2010
>
> The function, ext4_mb_free_metadata(), is called after
> ext4_mb_load_buddy(sb, block_group, &e4b);
> and before
> ext4_mb_release_desc(&e4b);
> in the function, ext4_mb_free_blocks(), so the bd_bitmap_page and
> bd_buddy_page of e4b are well managed.
>
> If for special purpose, page_cache_get() is issued on these two pages,
> there should also be page_cache_release() issued correspondingly, or
> the two pages are over pinned.
release_blocks_on_commit does that. I also have a comment around that page_cache_release.
>
> Cc: Theodore Ts'o <tytso@mit.edu>
> Cc: Andreas Dilger <adilger@sun.com>
> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
> Signed-off-by: Jing Zhang <zj.barak@gmail.com>
>
> ---
>
> --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
> +++ ext4_mm_leak/mballoc6.c 2010-03-24 20:31:52.000000000 +0800
> @@ -4361,15 +4361,6 @@ ext4_mb_free_metadata(handle_t *handle,
> new_node = &new_entry->node;
> block = new_entry->start_blk;
>
> - if (!*n) {
> - /* first free block exent. We need to
> - protect buddy cache from being freed,
> - * otherwise we'll refresh it from
> - * on-disk bitmap and lose not-yet-available
> - * blocks */
> - page_cache_get(e4b->bd_buddy_page);
> - page_cache_get(e4b->bd_bitmap_page);
> - }
> while (*n) {
> parent = *n;
> entry = rb_entry(parent, struct ext4_free_data, node);
-aneesh
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] ext4: page_cache pages over pinned in ext4_mb_free_metadata()
2010-03-24 17:16 ` Aneesh Kumar K. V
@ 2010-03-25 14:23 ` jing zhang
0 siblings, 0 replies; 3+ messages in thread
From: jing zhang @ 2010-03-25 14:23 UTC (permalink / raw)
To: Aneesh Kumar K. V
Cc: linux-ext4, Theodore Ts'o, Andreas Dilger, Dave Kleikamp
2010/3/25, Aneesh Kumar K. V <aneesh.kumar@linux.vnet.ibm.com>:
> On Wed, 24 Mar 2010 21:00:34 +0800, jing zhang <zj.barak@gmail.com> wrote:
>> From: Jing Zhang <zj.barak@gmail.com>
>>
>> Date: Wed Mar 24 20:38:48 2010
>>
>> The function, ext4_mb_free_metadata(), is called after
>> ext4_mb_load_buddy(sb, block_group, &e4b);
>> and before
>> ext4_mb_release_desc(&e4b);
>> in the function, ext4_mb_free_blocks(), so the bd_bitmap_page and
>> bd_buddy_page of e4b are well managed.
>>
>> If for special purpose, page_cache_get() is issued on these two pages,
>> there should also be page_cache_release() issued correspondingly, or
>> the two pages are over pinned.
>
> release_blocks_on_commit does that. I also have a comment around that
> page_cache_release.
Thank you, Aneesh. I will check it.
- zj
>
>>
>> Cc: Theodore Ts'o <tytso@mit.edu>
>> Cc: Andreas Dilger <adilger@sun.com>
>> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
>> Signed-off-by: Jing Zhang <zj.barak@gmail.com>
>>
>> ---
>>
>> --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800
>> +++ ext4_mm_leak/mballoc6.c 2010-03-24 20:31:52.000000000 +0800
>> @@ -4361,15 +4361,6 @@ ext4_mb_free_metadata(handle_t *handle,
>> new_node = &new_entry->node;
>> block = new_entry->start_blk;
>>
>> - if (!*n) {
>> - /* first free block exent. We need to
>> - protect buddy cache from being freed,
>> - * otherwise we'll refresh it from
>> - * on-disk bitmap and lose not-yet-available
>> - * blocks */
>> - page_cache_get(e4b->bd_buddy_page);
>> - page_cache_get(e4b->bd_bitmap_page);
>> - }
>> while (*n) {
>> parent = *n;
>> entry = rb_entry(parent, struct ext4_free_data, node);
>
>
> -aneesh
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-03-24 13:00 [PATCH] ext4: page_cache pages over pinned in ext4_mb_free_metadata() jing zhang
2010-03-24 17:16 ` Aneesh Kumar K. V
2010-03-25 14:23 ` jing zhang
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