* [PATCH] f2fs: avoid overflow when large directory feathure is enabled
@ 2014-05-27 1:06 Chao Yu
2014-05-27 6:23 ` Changman Lee
0 siblings, 1 reply; 3+ messages in thread
From: Chao Yu @ 2014-05-27 1:06 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
When large directory feathure is enable, We have one case which could cause
overflow in dir_buckets() as following:
special case: level + dir_level >= 32 and level < MAX_DIR_HASH_DEPTH / 2.
Here we define MAX_DIR_BUCKETS to limit the return value when the condition
could trigger potential overflow.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
fs/f2fs/dir.c | 4 ++--
include/linux/f2fs_fs.h | 3 +++
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index c3f1485..966acb0 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -23,10 +23,10 @@ static unsigned long dir_blocks(struct inode *inode)
static unsigned int dir_buckets(unsigned int level, int dir_level)
{
- if (level < MAX_DIR_HASH_DEPTH / 2)
+ if (level + dir_level < MAX_DIR_HASH_DEPTH / 2)
return 1 << (level + dir_level);
else
- return 1 << ((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1);
+ return MAX_DIR_BUCKETS;
}
static unsigned int bucket_blocks(unsigned int level)
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 8c03f71..ba6f312 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -394,6 +394,9 @@ typedef __le32 f2fs_hash_t;
/* MAX level for dir lookup */
#define MAX_DIR_HASH_DEPTH 63
+/* MAX buckets in one level of dir */
+#define MAX_DIR_BUCKETS (1 << ((MAX_DIR_HASH_DEPTH / 2) - 1))
+
#define SIZE_OF_DIR_ENTRY 11 /* by byte */
#define SIZE_OF_DENTRY_BITMAP ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
BITS_PER_BYTE)
--
1.7.10.4
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] f2fs: avoid overflow when large directory feathure is enabled
2014-05-27 1:06 [PATCH] f2fs: avoid overflow when large directory feathure is enabled Chao Yu
@ 2014-05-27 6:23 ` Changman Lee
2014-05-27 8:49 ` Chao Yu
0 siblings, 1 reply; 3+ messages in thread
From: Changman Lee @ 2014-05-27 6:23 UTC (permalink / raw)
To: Chao Yu; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
Hi, Chao
Good catch. Please, modify Documentation/filesytems/f2fs.txt
On Tue, May 27, 2014 at 09:06:52AM +0800, Chao Yu wrote:
> When large directory feathure is enable, We have one case which could cause
> overflow in dir_buckets() as following:
> special case: level + dir_level >= 32 and level < MAX_DIR_HASH_DEPTH / 2.
>
> Here we define MAX_DIR_BUCKETS to limit the return value when the condition
> could trigger potential overflow.
>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
> fs/f2fs/dir.c | 4 ++--
> include/linux/f2fs_fs.h | 3 +++
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index c3f1485..966acb0 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -23,10 +23,10 @@ static unsigned long dir_blocks(struct inode *inode)
>
> static unsigned int dir_buckets(unsigned int level, int dir_level)
> {
> - if (level < MAX_DIR_HASH_DEPTH / 2)
> + if (level + dir_level < MAX_DIR_HASH_DEPTH / 2)
> return 1 << (level + dir_level);
> else
> - return 1 << ((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1);
> + return MAX_DIR_BUCKETS;
> }
>
> static unsigned int bucket_blocks(unsigned int level)
> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
> index 8c03f71..ba6f312 100644
> --- a/include/linux/f2fs_fs.h
> +++ b/include/linux/f2fs_fs.h
> @@ -394,6 +394,9 @@ typedef __le32 f2fs_hash_t;
> /* MAX level for dir lookup */
> #define MAX_DIR_HASH_DEPTH 63
>
> +/* MAX buckets in one level of dir */
> +#define MAX_DIR_BUCKETS (1 << ((MAX_DIR_HASH_DEPTH / 2) - 1))
> +
> #define SIZE_OF_DIR_ENTRY 11 /* by byte */
> #define SIZE_OF_DENTRY_BITMAP ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
> BITS_PER_BYTE)
> --
> 1.7.10.4
>
>
>
> ------------------------------------------------------------------------------
> The best possible search technologies are now affordable for all companies.
> Download your FREE open source Enterprise Search Engine today!
> Our experts will assist you in its installation for $59/mo, no commitment.
> Test it for FREE on our Cloud platform anytime!
> http://pubads.g.doubleclick.net/gampad/clk?id=145328191&iu=/4140/ostg.clktrk
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
------------------------------------------------------------------------------
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] f2fs: avoid overflow when large directory feathure is enabled
2014-05-27 6:23 ` Changman Lee
@ 2014-05-27 8:49 ` Chao Yu
0 siblings, 0 replies; 3+ messages in thread
From: Chao Yu @ 2014-05-27 8:49 UTC (permalink / raw)
To: 'Changman Lee'; +Cc: linux-fsdevel, linux-kernel, linux-f2fs-devel
Hi changman,
> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Tuesday, May 27, 2014 2:23 PM
> To: Chao Yu
> Cc: Jaegeuk Kim; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid overflow when large directory feathure is enabled
>
> Hi, Chao
> Good catch. Please, modify Documentation/filesytems/f2fs.txt
Thank you for reminding me, I will add modification of f2fs.txt in the patch later.
>
> On Tue, May 27, 2014 at 09:06:52AM +0800, Chao Yu wrote:
> > When large directory feathure is enable, We have one case which could cause
> > overflow in dir_buckets() as following:
> > special case: level + dir_level >= 32 and level < MAX_DIR_HASH_DEPTH / 2.
> >
> > Here we define MAX_DIR_BUCKETS to limit the return value when the condition
> > could trigger potential overflow.
> >
> > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > ---
> > fs/f2fs/dir.c | 4 ++--
> > include/linux/f2fs_fs.h | 3 +++
> > 2 files changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> > index c3f1485..966acb0 100644
> > --- a/fs/f2fs/dir.c
> > +++ b/fs/f2fs/dir.c
> > @@ -23,10 +23,10 @@ static unsigned long dir_blocks(struct inode *inode)
> >
> > static unsigned int dir_buckets(unsigned int level, int dir_level)
> > {
> > - if (level < MAX_DIR_HASH_DEPTH / 2)
> > + if (level + dir_level < MAX_DIR_HASH_DEPTH / 2)
> > return 1 << (level + dir_level);
> > else
> > - return 1 << ((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1);
> > + return MAX_DIR_BUCKETS;
> > }
> >
> > static unsigned int bucket_blocks(unsigned int level)
> > diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
> > index 8c03f71..ba6f312 100644
> > --- a/include/linux/f2fs_fs.h
> > +++ b/include/linux/f2fs_fs.h
> > @@ -394,6 +394,9 @@ typedef __le32 f2fs_hash_t;
> > /* MAX level for dir lookup */
> > #define MAX_DIR_HASH_DEPTH 63
> >
> > +/* MAX buckets in one level of dir */
> > +#define MAX_DIR_BUCKETS (1 << ((MAX_DIR_HASH_DEPTH / 2) - 1))
> > +
> > #define SIZE_OF_DIR_ENTRY 11 /* by byte */
> > #define SIZE_OF_DENTRY_BITMAP ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
> > BITS_PER_BYTE)
> > --
> > 1.7.10.4
> >
> >
> >
> > ------------------------------------------------------------------------------
> > The best possible search technologies are now affordable for all companies.
> > Download your FREE open source Enterprise Search Engine today!
> > Our experts will assist you in its installation for $59/mo, no commitment.
> > Test it for FREE on our Cloud platform anytime!
> > http://pubads.g.doubleclick.net/gampad/clk?id=145328191&iu=/4140/ostg.clktrk
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
------------------------------------------------------------------------------
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-05-27 1:06 [PATCH] f2fs: avoid overflow when large directory feathure is enabled Chao Yu
2014-05-27 6:23 ` Changman Lee
2014-05-27 8:49 ` Chao Yu
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