* [RFC] ext4: fix a BUG in ext4_mpage_readpages()
@ 2015-11-04 7:58 yalin wang
2015-11-05 15:40 ` Jan Kara
0 siblings, 1 reply; 2+ messages in thread
From: yalin wang @ 2015-11-04 7:58 UTC (permalink / raw)
To: tytso, adilger.kernel, linux-ext4, linux-kernel; +Cc: yalin wang
The last block should be the total read pages last block,
need adjust the block number when caculate every page.
Signed-off-by: yalin wang <yalin.wang2010@gmail.com>
---
fs/ext4/readpage.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 5dc5e95..d20c39d 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -174,7 +174,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
goto confused;
block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
- last_block = block_in_file + nr_pages * blocks_per_page;
+ last_block = block_in_file + (nr_pages - page_idx) * blocks_per_page;
last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
if (last_block > last_block_in_file)
last_block = last_block_in_file;
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [RFC] ext4: fix a BUG in ext4_mpage_readpages()
2015-11-04 7:58 [RFC] ext4: fix a BUG in ext4_mpage_readpages() yalin wang
@ 2015-11-05 15:40 ` Jan Kara
0 siblings, 0 replies; 2+ messages in thread
From: Jan Kara @ 2015-11-05 15:40 UTC (permalink / raw)
To: yalin wang; +Cc: tytso, adilger.kernel, linux-ext4, linux-kernel
On Wed 04-11-15 15:58:34, yalin wang wrote:
> The last block should be the total read pages last block,
> need adjust the block number when caculate every page.
>
> Signed-off-by: yalin wang <yalin.wang2010@gmail.com>
> ---
> fs/ext4/readpage.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
> index 5dc5e95..d20c39d 100644
> --- a/fs/ext4/readpage.c
> +++ b/fs/ext4/readpage.c
> @@ -174,7 +174,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
> goto confused;
>
> block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
> - last_block = block_in_file + nr_pages * blocks_per_page;
> + last_block = block_in_file + (nr_pages - page_idx) * blocks_per_page;
I don't think your patch is correct. The for loop decrements nr_pages at each
iteration so the original code looks fine... Or which problems do you
observe?
Honza
> last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
> if (last_block > last_block_in_file)
> last_block = last_block_in_file;
> --
> 1.9.1
>
> --
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--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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