[PATCH] btrfs-progs: Replace hardcoded PAGE_CACHE_SIZE with getpagesize().

[PATCH] btrfs-progs: Replace hardcoded PAGE_CACHE_SIZE with getpagesize().

[Feifei Xu]

PAGE_CACHE_SIZE is hardcoded to 4K in cmds-restore.c. It makes lzo
decompress fail on ppc64. Fix this through replacing hardcoded 4K
with getpagesize().

Signed-off-by: Feifei Xu <xufeifei@linux.vnet.ibm.com>
---
 cmds-restore.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/cmds-restore.c b/cmds-restore.c
index 161fd91..17a5475 100644
--- a/cmds-restore.c
+++ b/cmds-restore.c
@@ -56,7 +56,6 @@ static int get_xattrs = 0;
 static int dry_run = 0;
 
 #define LZO_LEN 4
-#define PAGE_CACHE_SIZE 4096
 #define lzo1x_worst_compress(x) ((x) + ((x) / 16) + 64 + 3)
 
 static int decompress_zlib(char *inbuf, char *outbuf, u64 compress_len,
@@ -127,7 +126,7 @@ static int decompress_lzo(unsigned char *inbuf, char *outbuf, u64 compress_len,
 		inbuf += LZO_LEN;
 		tot_in += LZO_LEN;
 
-		new_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
+		new_len = lzo1x_worst_compress(getpagesize());
 		ret = lzo1x_decompress_safe((const unsigned char *)inbuf, in_len,
 					    (unsigned char *)outbuf,
 					    (void *)&new_len, NULL);
@@ -144,8 +143,8 @@ static int decompress_lzo(unsigned char *inbuf, char *outbuf, u64 compress_len,
 		 * If the 4 byte header does not fit to the rest of the page we
 		 * have to move to the next one, unless we read some garbage
 		 */
-		mod_page = tot_in % PAGE_CACHE_SIZE;
-		rem_page = PAGE_CACHE_SIZE - mod_page;
+		mod_page = tot_in % getpagesize();
+		rem_page = getpagesize() - mod_page;
 		if (rem_page < LZO_LEN) {
 			inbuf += rem_page;
 			tot_in += rem_page;
-- 
1.9.1

Re: [PATCH] btrfs-progs: Replace hardcoded PAGE_CACHE_SIZE with getpagesize().

[David Sterba]

On Wed, Mar 09, 2016 at 08:22:13PM +0800, Feifei Xu wrote:
> PAGE_CACHE_SIZE is hardcoded to 4K in cmds-restore.c. It makes lzo
> decompress fail on ppc64. Fix this through replacing hardcoded 4K
> with getpagesize().

You're right that the hardcoded value is a bug, but the correct value is
the sector size. Ie. when the system is 4k page size and filesystem is
eg. from ppc64.

Re: [PATCH] btrfs-progs: Replace hardcoded PAGE_CACHE_SIZE with getpagesize().

[Fiona]

On 2016/3/9 20:45, David Sterba wrote:
> On Wed, Mar 09, 2016 at 08:22:13PM +0800, Feifei Xu wrote:
>> PAGE_CACHE_SIZE is hardcoded to 4K in cmds-restore.c. It makes lzo
>> decompress fail on ppc64. Fix this through replacing hardcoded 4K
>> with getpagesize().
> You're right that the hardcoded value is a bug, but the correct value is
> the sector size. Ie. when the system is 4k page size and filesystem is
> eg. from ppc64.
Hi David,

You're right, I am working to fix it.

Thanks
Fiona