* [PATCH] btrfs: fix memory leak for page count
@ 2020-07-17 10:22 robbieko
2020-07-17 12:00 ` Filipe Manana
0 siblings, 1 reply; 4+ messages in thread
From: robbieko @ 2020-07-17 10:22 UTC (permalink / raw)
To: linux-btrfs; +Cc: Robbie Ko
From: Robbie Ko <robbieko@synology.com>
When lock_delalloc_page, we first lock the page and then
check that the page dirty, if the page is not dirty, we
will return -EAGAIN but all pages must be freed, otherwise
page leak.
Signed-off-by: Robbie Ko <robbieko@synology.com>
---
fs/btrfs/extent_io.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 68c96057ad2d..34d55b1e2a88 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1951,7 +1951,7 @@ static int __process_pages_contig(struct address_space *mapping,
struct page *pages[16];
unsigned ret;
int err = 0;
- int i;
+ int i, j;
if (page_ops & PAGE_LOCK) {
ASSERT(page_ops == PAGE_LOCK);
@@ -1999,7 +1999,8 @@ static int __process_pages_contig(struct address_space *mapping,
if (!PageDirty(pages[i]) ||
pages[i]->mapping != mapping) {
unlock_page(pages[i]);
- put_page(pages[i]);
+ for (j = i; j < ret; j++)
+ put_page(pages[j]);
err = -EAGAIN;
goto out;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: fix memory leak for page count
2020-07-17 10:22 [PATCH] btrfs: fix memory leak for page count robbieko
@ 2020-07-17 12:00 ` Filipe Manana
2020-07-17 12:27 ` Nikolay Borisov
2020-07-20 1:27 ` Robbie Ko
0 siblings, 2 replies; 4+ messages in thread
From: Filipe Manana @ 2020-07-17 12:00 UTC (permalink / raw)
To: robbieko; +Cc: linux-btrfs
On Fri, Jul 17, 2020 at 11:23 AM robbieko <robbieko@synology.com> wrote:
>
> From: Robbie Ko <robbieko@synology.com>
>
> When lock_delalloc_page, we first lock the page and then
> check that the page dirty, if the page is not dirty, we
> will return -EAGAIN but all pages must be freed, otherwise
> page leak.
"When lock_delalloc_page" -> When locking pages for delalloc
We check if it's dirty and if the mapping still matches.
Btw, you can make line length closer to 75 characters, it makes things
a bit more readable.
The subject is also a bit confusing:
"btrfs: fix memory leak for page count"
something along the lines "btrfs: fix page leaks after failure to lock
page for delalloc" would be more clear to me at least,
it gives a clue about where the problem is.
>
> Signed-off-by: Robbie Ko <robbieko@synology.com>
The code looks correct, thanks.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
> ---
> fs/btrfs/extent_io.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 68c96057ad2d..34d55b1e2a88 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -1951,7 +1951,7 @@ static int __process_pages_contig(struct address_space *mapping,
> struct page *pages[16];
> unsigned ret;
> int err = 0;
> - int i;
> + int i, j;
>
> if (page_ops & PAGE_LOCK) {
> ASSERT(page_ops == PAGE_LOCK);
> @@ -1999,7 +1999,8 @@ static int __process_pages_contig(struct address_space *mapping,
> if (!PageDirty(pages[i]) ||
> pages[i]->mapping != mapping) {
> unlock_page(pages[i]);
> - put_page(pages[i]);
> + for (j = i; j < ret; j++)
> + put_page(pages[j]);
> err = -EAGAIN;
> goto out;
> }
> --
> 2.17.1
>
--
Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: fix memory leak for page count
2020-07-17 12:00 ` Filipe Manana
@ 2020-07-17 12:27 ` Nikolay Borisov
2020-07-20 1:27 ` Robbie Ko
1 sibling, 0 replies; 4+ messages in thread
From: Nikolay Borisov @ 2020-07-17 12:27 UTC (permalink / raw)
To: fdmanana, robbieko; +Cc: linux-btrfs
On 17.07.20 г. 15:00 ч., Filipe Manana wrote:
> On Fri, Jul 17, 2020 at 11:23 AM robbieko <robbieko@synology.com> wrote:
>>
>> From: Robbie Ko <robbieko@synology.com>
>>
>> When lock_delalloc_page, we first lock the page and then
>> check that the page dirty, if the page is not dirty, we
>> will return -EAGAIN but all pages must be freed, otherwise
>> page leak.
>
> "When lock_delalloc_page" -> When locking pages for delalloc
>
> We check if it's dirty and if the mapping still matches.
>
> Btw, you can make line length closer to 75 characters, it makes things
> a bit more readable.
>
> The subject is also a bit confusing:
>
> "btrfs: fix memory leak for page count"
>
> something along the lines "btrfs: fix page leaks after failure to lock
> page for delalloc" would be more clear to me at least,
> it gives a clue about where the problem is.
>
>>
>> Signed-off-by: Robbie Ko <robbieko@synology.com>
>
> The code looks correct, thanks.
>
> Reviewed-by: Filipe Manana <fdmanana@suse.com>
>
>> ---
>> fs/btrfs/extent_io.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>> index 68c96057ad2d..34d55b1e2a88 100644
>> --- a/fs/btrfs/extent_io.c
>> +++ b/fs/btrfs/extent_io.c
>> @@ -1951,7 +1951,7 @@ static int __process_pages_contig(struct address_space *mapping,
>> struct page *pages[16];
>> unsigned ret;
>> int err = 0;
>> - int i;
>> + int i, j;
>>
>> if (page_ops & PAGE_LOCK) {
>> ASSERT(page_ops == PAGE_LOCK);
>> @@ -1999,7 +1999,8 @@ static int __process_pages_contig(struct address_space *mapping,
>> if (!PageDirty(pages[i]) ||
>> pages[i]->mapping != mapping) {
>> unlock_page(pages[i]);
>> - put_page(pages[i]);
>> + for (j = i; j < ret; j++)
>> + put_page(pages[j]);
nit: You don't need to introduce another variable, you can simply reuse
i from its current value:
for(; i < ret; i++)
put_pages(pages[j]
If 'j' is to be used I'da rather have it defined in the 'if' branch so
it's lifespan is clearly visible.
>> err = -EAGAIN;
>> goto out;
>> }
>> --
>> 2.17.1
>>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: fix memory leak for page count
2020-07-17 12:00 ` Filipe Manana
2020-07-17 12:27 ` Nikolay Borisov
@ 2020-07-20 1:27 ` Robbie Ko
1 sibling, 0 replies; 4+ messages in thread
From: Robbie Ko @ 2020-07-20 1:27 UTC (permalink / raw)
To: fdmanana; +Cc: linux-btrfs
Filipe Manana 於 2020/7/17 下午8:00 寫道:
> On Fri, Jul 17, 2020 at 11:23 AM robbieko <robbieko@synology.com> wrote:
>> From: Robbie Ko <robbieko@synology.com>
>>
>> When lock_delalloc_page, we first lock the page and then
>> check that the page dirty, if the page is not dirty, we
>> will return -EAGAIN but all pages must be freed, otherwise
>> page leak.
> "When lock_delalloc_page" -> When locking pages for delalloc
>
> We check if it's dirty and if the mapping still matches.
>
> Btw, you can make line length closer to 75 characters, it makes things
> a bit more readable.
>
> The subject is also a bit confusing:
>
> "btrfs: fix memory leak for page count"
>
> something along the lines "btrfs: fix page leaks after failure to lock
> page for delalloc" would be more clear to me at least,
> it gives a clue about where the problem is.
OK, I will resend patch.
Thanks.
>> Signed-off-by: Robbie Ko <robbieko@synology.com>
> The code looks correct, thanks.
>
> Reviewed-by: Filipe Manana <fdmanana@suse.com>
>
>> ---
>> fs/btrfs/extent_io.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
>> index 68c96057ad2d..34d55b1e2a88 100644
>> --- a/fs/btrfs/extent_io.c
>> +++ b/fs/btrfs/extent_io.c
>> @@ -1951,7 +1951,7 @@ static int __process_pages_contig(struct address_space *mapping,
>> struct page *pages[16];
>> unsigned ret;
>> int err = 0;
>> - int i;
>> + int i, j;
>>
>> if (page_ops & PAGE_LOCK) {
>> ASSERT(page_ops == PAGE_LOCK);
>> @@ -1999,7 +1999,8 @@ static int __process_pages_contig(struct address_space *mapping,
>> if (!PageDirty(pages[i]) ||
>> pages[i]->mapping != mapping) {
>> unlock_page(pages[i]);
>> - put_page(pages[i]);
>> + for (j = i; j < ret; j++)
>> + put_page(pages[j]);
>> err = -EAGAIN;
>> goto out;
>> }
>> --
>> 2.17.1
>>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-07-20 1:27 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-07-17 10:22 [PATCH] btrfs: fix memory leak for page count robbieko
2020-07-17 12:00 ` Filipe Manana
2020-07-17 12:27 ` Nikolay Borisov
2020-07-20 1:27 ` Robbie Ko
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