On 09/26/2013 05:32 AM, Dave Chinner wrote: > On Wed, Sep 25, 2013 at 04:10:20PM +0800, Jeff Liu wrote: >> From: Jie Liu <jeff.liu@xxxxxxxxxx> >> >> Write a file with an offset greater than 16TB on 32-bit system and >> then trigger page write-back via sync(1) as below will cause the >> task hang in a little while: > > [snip] > >> This patch just fixed both issues. >> >> Reported-by: Michael L. Semon <mlsemon35@xxxxxxxxx> >> Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx> >> --- >> v2: don't reset the s_max_bytes to MAX_LFS_FILESIZE, instead, revise the page offset >> check up strategy to avoid the potential overflow. >> v1: http://oss.sgi.com/archives/xfs/2013-07/msg00154.html >> >> fs/xfs/xfs_aops.c | 11 ++++++----- >> 1 file changed, 6 insertions(+), 5 deletions(-) >> >> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c >> index 41a6950..6059d00 100644 >> --- a/fs/xfs/xfs_aops.c >> +++ b/fs/xfs/xfs_aops.c >> @@ -969,7 +969,9 @@ xfs_vm_writepage( >> offset = i_size_read(inode); >> end_index = offset >> PAGE_CACHE_SHIFT; >> last_index = (offset - 1) >> PAGE_CACHE_SHIFT; >> - if (page->index >= end_index) { >> + if (page->index < end_index) >> + end_offset = (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT; >> + else { >> unsigned offset_into_page = offset & (PAGE_CACHE_SIZE - 1); > > The logic here is already difficult to understand, and the fact that > the code that has 32 bit overflow issues is not obvious . Can you > add a comment noting the overflow issue being handled here? > >> >> /* >> @@ -978,7 +980,8 @@ xfs_vm_writepage( >> * page so that reclaim stops reclaiming it. Otherwise >> * xfs_vm_releasepage() is called on it and gets confused. >> */ >> - if (page->index >= end_index + 1 || offset_into_page == 0) >> + if (page->index > end_index || >> + (page->index == end_index && offset_into_page == 0)) >> goto redirty; > > And again here? > > That means in future we will be aware of the problem when reading > the code... Fair enough, will post a new version at a latter time. Thanks, -Jeff _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
