Re: [PATCH v4] btrfs-progs: fix page align issue for lzo compress in restore
On Thu, Nov 27, 2014 at 11:02:38AM +0800, Gui Hecheng wrote: > I note that this patch is not yet in the latest integration, how's the > fix going? The patch was still buggy, a fix will land in 3.18.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4] btrfs-progs: fix page align issue for lzo compress in restore
On Tue, 2014-10-14 at 11:32 +0200, David Sterba wrote: > On Tue, Oct 14, 2014 at 10:06:16AM +0200, Marc Dietrich wrote: > > This hasn't landed in an btrfs-progs branch I found. Any update? > > I had it tagged for review and found something that needs fixing. The > PAGE_CACHE_SIZE is hardcoded to 4k, this will break on filesystems with > larger sectors (eg. the powerpc machines). I'll scheudule the patch post > 3.17, with a fix. Hi David， I note that this patch is not yet in the latest integration, how's the fix going? -Gui -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4] btrfs-progs: fix page align issue for lzo compress in restore
On Tue, Oct 14, 2014 at 10:06:16AM +0200, Marc Dietrich wrote: > This hasn't landed in an btrfs-progs branch I found. Any update? I had it tagged for review and found something that needs fixing. The PAGE_CACHE_SIZE is hardcoded to 4k, this will break on filesystems with larger sectors (eg. the powerpc machines). I'll scheudule the patch post 3.17, with a fix. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4] btrfs-progs: fix page align issue for lzo compress in restore
This hasn't landed in an btrfs-progs branch I found. Any update?
Marc
Am Dienstag, 23. September 2014, 16:34:54 schrieb Gui Hecheng:
> When runing restore under lzo compression, "bad compress length"
> problems are encountered.
> It is because there is a page align problem with the @decompress_lzo,
>
> as follows:
> |--| ||-| |--|...|--|
>
> page ^page page
>
> 3 bytes left
>
> When lzo compress pages im RAM, lzo will ensure that
> the 4 bytes len will be in one page as a whole.
> There is a situation that 3 (or less) bytes are left
> at the end of a page, and then the 4 bytes len is
> stored at the start of the next page.
> But the @decompress_lzo doesn't goto the start of
> the next page and continue to read the next 4 bytes
> which is across two pages, so a random value is fetched
> as a "bad compress length".
>
> So we check page alignment every time before we are going to
> fetch the next @len and after the former piece of data is decompressed.
> If the current page that we reach has less than 4 bytes left,
> then we should fetch the next @len at the start of next page.
>
> Signed-off-by: Gui Hecheng
> Reviewed-by: Marc Dietrich
> ---
> changelog
> v1->v2: adopt alignment check method suggested by Marc
> v2->v3: make code more readable
> v3->v4: keep type safety & reformat comments
> ---
> cmds-restore.c | 27 +--
> 1 file changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/cmds-restore.c b/cmds-restore.c
> index e09acc4..1fe2df0 100644
> --- a/cmds-restore.c
> +++ b/cmds-restore.c
> @@ -56,7 +56,10 @@ static int get_xattrs = 0;
> static int dry_run = 0;
>
> #define LZO_LEN 4
> -#define PAGE_CACHE_SIZE 4096
> +#define PAGE_CACHE_SIZE 4096UL
> +#define PAGE_CACHE_MASK (~(PAGE_CACHE_SIZE - 1))
> +#define PAGE_CACHE_ALIGN(addr) (((addr) + PAGE_CACHE_SIZE - 1) \
> + & PAGE_CACHE_MASK)
> #define lzo1x_worst_compress(x) ((x) + ((x) / 16) + 64 + 3)
>
> static int decompress_zlib(char *inbuf, char *outbuf, u64 compress_len,
> @@ -93,6 +96,26 @@ static inline size_t read_compress_length(unsigned char
> *buf) return le32_to_cpu(dlen);
> }
>
> +static void align_if_need(size_t *tot_in, size_t *in_len)
> +{
> + size_t tot_in_aligned;
> + size_t bytes_left;
> +
> + tot_in_aligned = PAGE_CACHE_ALIGN(*tot_in);
> + bytes_left = tot_in_aligned - *tot_in;
> +
> + if (bytes_left >= LZO_LEN)
> + return;
> +
> + /*
> + * The LZO_LEN bytes is guaranteed to be in one page as a whole,
> + * so if a page has fewer than LZO_LEN bytes left, the LZO_LEN bytes
> + * should be fetched at the start of the next page
> + */
> + *in_len += bytes_left;
> + *tot_in = tot_in_aligned;
> +}
> +
> static int decompress_lzo(unsigned char *inbuf, char *outbuf, u64
> compress_len, u64 *decompress_len)
> {
> @@ -135,8 +158,8 @@ static int decompress_lzo(unsigned char *inbuf, char
> *outbuf, u64 compress_len, }
> out_len += new_len;
> outbuf += new_len;
> + align_if_need(&tot_in, &in_len);
> inbuf += in_len;
> - tot_in += in_len;
> }
>
> *decompress_len = out_len;
signature.asc
Description: This is a digitally signed message part.
[PATCH v4] btrfs-progs: fix page align issue for lzo compress in restore
When runing restore under lzo compression, "bad compress length"
problems are encountered.
It is because there is a page align problem with the @decompress_lzo,
as follows:
|--| ||-| |--|...|--|
page ^page page
|
3 bytes left
When lzo compress pages im RAM, lzo will ensure that
the 4 bytes len will be in one page as a whole.
There is a situation that 3 (or less) bytes are left
at the end of a page, and then the 4 bytes len is
stored at the start of the next page.
But the @decompress_lzo doesn't goto the start of
the next page and continue to read the next 4 bytes
which is across two pages, so a random value is fetched
as a "bad compress length".
So we check page alignment every time before we are going to
fetch the next @len and after the former piece of data is decompressed.
If the current page that we reach has less than 4 bytes left,
then we should fetch the next @len at the start of next page.
Signed-off-by: Gui Hecheng
Reviewed-by: Marc Dietrich
---
changelog
v1->v2: adopt alignment check method suggested by Marc
v2->v3: make code more readable
v3->v4: keep type safety & reformat comments
---
cmds-restore.c | 27 +--
1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/cmds-restore.c b/cmds-restore.c
index e09acc4..1fe2df0 100644
--- a/cmds-restore.c
+++ b/cmds-restore.c
@@ -56,7 +56,10 @@ static int get_xattrs = 0;
static int dry_run = 0;
#define LZO_LEN 4
-#define PAGE_CACHE_SIZE 4096
+#define PAGE_CACHE_SIZE 4096UL
+#define PAGE_CACHE_MASK (~(PAGE_CACHE_SIZE - 1))
+#define PAGE_CACHE_ALIGN(addr) (((addr) + PAGE_CACHE_SIZE - 1) \
+ & PAGE_CACHE_MASK)
#define lzo1x_worst_compress(x) ((x) + ((x) / 16) + 64 + 3)
static int decompress_zlib(char *inbuf, char *outbuf, u64 compress_len,
@@ -93,6 +96,26 @@ static inline size_t read_compress_length(unsigned char *buf)
return le32_to_cpu(dlen);
}
+static void align_if_need(size_t *tot_in, size_t *in_len)
+{
+ size_t tot_in_aligned;
+ size_t bytes_left;
+
+ tot_in_aligned = PAGE_CACHE_ALIGN(*tot_in);
+ bytes_left = tot_in_aligned - *tot_in;
+
+ if (bytes_left >= LZO_LEN)
+ return;
+
+ /*
+* The LZO_LEN bytes is guaranteed to be in one page as a whole,
+* so if a page has fewer than LZO_LEN bytes left, the LZO_LEN bytes
+* should be fetched at the start of the next page
+*/
+ *in_len += bytes_left;
+ *tot_in = tot_in_aligned;
+}
+
static int decompress_lzo(unsigned char *inbuf, char *outbuf, u64 compress_len,
u64 *decompress_len)
{
@@ -135,8 +158,8 @@ static int decompress_lzo(unsigned char *inbuf, char
*outbuf, u64 compress_len,
}
out_len += new_len;
outbuf += new_len;
+ align_if_need(&tot_in, &in_len);
inbuf += in_len;
- tot_in += in_len;
}
*decompress_len = out_len;
--
1.8.1.4
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Re: [PATCH v4] btrfs-progs: fix page align issue for lzo compress in restore
On Tue, 2014-09-23 at 10:25 +0800, Gui Hecheng wrote:
> When runing restore under lzo compression, "bad compress length"
> problems are encountered.
> It is because there is a page align problem with the @decompress_lzo,
> as follows:
> |--| ||-| |--|...|--|
> page ^page page
> |
> 3 bytes left
>
> When lzo compress pages im RAM, lzo will ensure that
> the 4 bytes len will be in one page as a whole.
> There is a situation that 3 (or less) bytes are left
> at the end of a page, and then the 4 bytes len is
> stored at the start of the next page.
> But the @decompress_lzo doesn't goto the start of
> the next page and continue to read the next 4 bytes
> which is across two pages, so a random value is fetched
> as a "bad compress length".
>
> So we check page alignment every time before we are going to
> fetch the next @len and after the former piece of data is decompressed.
> If the current page that we reach has less than 4 bytes left,
> then we should fetch the next @len at the start of next page.
>
> Signed-off-by: Gui Hecheng
> Reviewed-by: Marc Dietrich
> ---
> changelog
> v1->v2: adopt alignment check method suggested by Marc
> v2->v3: make code more readable
> v3->v4: keep type safety
> ---
> cmds-restore.c | 29 +++--
> 1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/cmds-restore.c b/cmds-restore.c
> index 38a131e..fa5d5d1 100644
> --- a/cmds-restore.c
> +++ b/cmds-restore.c
> @@ -56,7 +56,10 @@ static int get_xattrs = 0;
> static int dry_run = 0;
>
> #define LZO_LEN 4
> -#define PAGE_CACHE_SIZE 4096
> +#define PAGE_CACHE_SIZE 4096UL
> +#define PAGE_CACHE_MASK (~(PAGE_CACHE_SIZE - 1))
> +#define PAGE_CACHE_ALIGN(addr) (((addr) + PAGE_CACHE_SIZE - 1) \
> + & PAGE_CACHE_MASK)
> #define lzo1x_worst_compress(x) ((x) + ((x) / 16) + 64 + 3)
>
> static int decompress_zlib(char *inbuf, char *outbuf, u64 compress_len,
> @@ -93,6 +96,28 @@ static inline size_t read_compress_length(unsigned char
> *buf)
> return le32_to_cpu(dlen);
> }
>
> +static void align_if_need(size_t *tot_in, size_t *in_len)
> +{
> + size_t tot_in_aligned;
> + size_t bytes_left;
> +
> + tot_in_aligned = PAGE_CACHE_ALIGN(*tot_in);
> + bytes_left = tot_in_aligned - *tot_in;
> +
> + if (bytes_left >= LZO_LEN)
> + return;
> +
> + /*
> + * The LZO_LEN bytes is guaranteed to be
> + * in one page as a whole, so if a page
> + * has fewer than LZO_LEN bytes left,
> + * the LZO_LEN bytes should be fetched
> + * at the start of the next page
> + */
> + *in_len += bytes_left;
> + *tot_in = tot_in_aligned;
> +}
> +
> static int decompress_lzo(unsigned char *inbuf, char *outbuf, u64
> compress_len,
> u64 *decompress_len)
> {
> @@ -135,8 +160,8 @@ static int decompress_lzo(unsigned char *inbuf, char
> *outbuf, u64 compress_len,
> }
> out_len += new_len;
> outbuf += new_len;
> + align_if_need(&tot_in, &in_len);
> inbuf += in_len;
> - tot_in += in_len;
> }
>
> *decompress_len = out_len;
Sorry, please scratch this one, the comments should be reformated.
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[PATCH v4] btrfs-progs: fix page align issue for lzo compress in restore
When runing restore under lzo compression, "bad compress length"
problems are encountered.
It is because there is a page align problem with the @decompress_lzo,
as follows:
|--| ||-| |--|...|--|
page ^page page
|
3 bytes left
When lzo compress pages im RAM, lzo will ensure that
the 4 bytes len will be in one page as a whole.
There is a situation that 3 (or less) bytes are left
at the end of a page, and then the 4 bytes len is
stored at the start of the next page.
But the @decompress_lzo doesn't goto the start of
the next page and continue to read the next 4 bytes
which is across two pages, so a random value is fetched
as a "bad compress length".
So we check page alignment every time before we are going to
fetch the next @len and after the former piece of data is decompressed.
If the current page that we reach has less than 4 bytes left,
then we should fetch the next @len at the start of next page.
Signed-off-by: Gui Hecheng
Reviewed-by: Marc Dietrich
---
changelog
v1->v2: adopt alignment check method suggested by Marc
v2->v3: make code more readable
v3->v4: keep type safety
---
cmds-restore.c | 29 +++--
1 file changed, 27 insertions(+), 2 deletions(-)
diff --git a/cmds-restore.c b/cmds-restore.c
index 38a131e..fa5d5d1 100644
--- a/cmds-restore.c
+++ b/cmds-restore.c
@@ -56,7 +56,10 @@ static int get_xattrs = 0;
static int dry_run = 0;
#define LZO_LEN 4
-#define PAGE_CACHE_SIZE 4096
+#define PAGE_CACHE_SIZE 4096UL
+#define PAGE_CACHE_MASK (~(PAGE_CACHE_SIZE - 1))
+#define PAGE_CACHE_ALIGN(addr) (((addr) + PAGE_CACHE_SIZE - 1) \
+ & PAGE_CACHE_MASK)
#define lzo1x_worst_compress(x) ((x) + ((x) / 16) + 64 + 3)
static int decompress_zlib(char *inbuf, char *outbuf, u64 compress_len,
@@ -93,6 +96,28 @@ static inline size_t read_compress_length(unsigned char *buf)
return le32_to_cpu(dlen);
}
+static void align_if_need(size_t *tot_in, size_t *in_len)
+{
+ size_t tot_in_aligned;
+ size_t bytes_left;
+
+ tot_in_aligned = PAGE_CACHE_ALIGN(*tot_in);
+ bytes_left = tot_in_aligned - *tot_in;
+
+ if (bytes_left >= LZO_LEN)
+ return;
+
+ /*
+* The LZO_LEN bytes is guaranteed to be
+* in one page as a whole, so if a page
+* has fewer than LZO_LEN bytes left,
+* the LZO_LEN bytes should be fetched
+* at the start of the next page
+*/
+ *in_len += bytes_left;
+ *tot_in = tot_in_aligned;
+}
+
static int decompress_lzo(unsigned char *inbuf, char *outbuf, u64 compress_len,
u64 *decompress_len)
{
@@ -135,8 +160,8 @@ static int decompress_lzo(unsigned char *inbuf, char
*outbuf, u64 compress_len,
}
out_len += new_len;
outbuf += new_len;
+ align_if_need(&tot_in, &in_len);
inbuf += in_len;
- tot_in += in_len;
}
*decompress_len = out_len;
--
1.8.1.4
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