From: Peter Zijlstra <a.p.zijlstra@chello.nl> To: Nick Piggin <npiggin@suse.de> Cc: Linux Memory Management <linux-mm@kvack.org>, Linux Kernel <linux-kernel@vger.kernel.org>, Linux Filesystems <linux-fsdevel@vger.kernel.org>, Andrew Morton <akpm@osdl.org> Subject: Re: [patch 6/10] mm: be sure to trim blocks Date: Tue, 16 Jan 2007 18:36:24 +0100 [thread overview] Message-ID: <1168968985.5975.30.camel@lappy> (raw) In-Reply-To: <20070113011255.9449.33228.sendpatchset@linux.site> On Sat, 2007-01-13 at 04:25 +0100, Nick Piggin wrote: > If prepare_write fails with AOP_TRUNCATED_PAGE, or if commit_write fails, then > we may have failed the write operation despite prepare_write having > instantiated blocks past i_size. Fix this, and consolidate the trimming into > one place. > > Signed-off-by: Nick Piggin <npiggin@suse.de> > > Index: linux-2.6/mm/filemap.c > =================================================================== > --- linux-2.6.orig/mm/filemap.c > +++ linux-2.6/mm/filemap.c > @@ -1911,22 +1911,9 @@ generic_file_buffered_write(struct kiocb > } > > status = a_ops->prepare_write(file, page, offset, offset+bytes); > - if (unlikely(status)) { > - loff_t isize = i_size_read(inode); > + if (unlikely(status)) > + goto fs_write_aop_error; > > - if (status != AOP_TRUNCATED_PAGE) > - unlock_page(page); > - page_cache_release(page); > - if (status == AOP_TRUNCATED_PAGE) > - continue; > - /* > - * prepare_write() may have instantiated a few blocks > - * outside i_size. Trim these off again. > - */ > - if (pos + bytes > isize) > - vmtruncate(inode, isize); > - break; > - } > if (likely(nr_segs == 1)) > copied = filemap_copy_from_user(page, offset, > buf, bytes); > @@ -1935,10 +1922,9 @@ generic_file_buffered_write(struct kiocb > cur_iov, iov_offset, bytes); > flush_dcache_page(page); > status = a_ops->commit_write(file, page, offset, offset+bytes); > - if (status == AOP_TRUNCATED_PAGE) { > - page_cache_release(page); > - continue; > - } > + if (unlikely(status)) > + goto fs_write_aop_error; > + I don't think this is correct, see how status >= 0 is used a few lines downwards. Perhaps something along the lines of an is_positive_aop_return() to test on? > if (likely(copied > 0)) { > if (!status) > status = copied; > @@ -1969,6 +1955,25 @@ generic_file_buffered_write(struct kiocb > break; > balance_dirty_pages_ratelimited(mapping); > cond_resched(); > + continue; > + > +fs_write_aop_error: > + if (status != AOP_TRUNCATED_PAGE) > + unlock_page(page); > + page_cache_release(page); > + > + /* > + * prepare_write() may have instantiated a few blocks > + * outside i_size. Trim these off again. Don't need > + * i_size_read because we hold i_mutex. > + */ > + if (pos + bytes > inode->i_size) > + vmtruncate(inode, inode->i_size); > + if (status == AOP_TRUNCATED_PAGE) > + continue; > + else > + break; > + > } while (count); > *ppos = pos;
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <a.p.zijlstra@chello.nl> To: Nick Piggin <npiggin@suse.de> Cc: Linux Memory Management <linux-mm@kvack.org>, Linux Kernel <linux-kernel@vger.kernel.org>, Linux Filesystems <linux-fsdevel@vger.kernel.org>, Andrew Morton <akpm@osdl.org> Subject: Re: [patch 6/10] mm: be sure to trim blocks Date: Tue, 16 Jan 2007 18:36:24 +0100 [thread overview] Message-ID: <1168968985.5975.30.camel@lappy> (raw) In-Reply-To: <20070113011255.9449.33228.sendpatchset@linux.site> On Sat, 2007-01-13 at 04:25 +0100, Nick Piggin wrote: > If prepare_write fails with AOP_TRUNCATED_PAGE, or if commit_write fails, then > we may have failed the write operation despite prepare_write having > instantiated blocks past i_size. Fix this, and consolidate the trimming into > one place. > > Signed-off-by: Nick Piggin <npiggin@suse.de> > > Index: linux-2.6/mm/filemap.c > =================================================================== > --- linux-2.6.orig/mm/filemap.c > +++ linux-2.6/mm/filemap.c > @@ -1911,22 +1911,9 @@ generic_file_buffered_write(struct kiocb > } > > status = a_ops->prepare_write(file, page, offset, offset+bytes); > - if (unlikely(status)) { > - loff_t isize = i_size_read(inode); > + if (unlikely(status)) > + goto fs_write_aop_error; > > - if (status != AOP_TRUNCATED_PAGE) > - unlock_page(page); > - page_cache_release(page); > - if (status == AOP_TRUNCATED_PAGE) > - continue; > - /* > - * prepare_write() may have instantiated a few blocks > - * outside i_size. Trim these off again. > - */ > - if (pos + bytes > isize) > - vmtruncate(inode, isize); > - break; > - } > if (likely(nr_segs == 1)) > copied = filemap_copy_from_user(page, offset, > buf, bytes); > @@ -1935,10 +1922,9 @@ generic_file_buffered_write(struct kiocb > cur_iov, iov_offset, bytes); > flush_dcache_page(page); > status = a_ops->commit_write(file, page, offset, offset+bytes); > - if (status == AOP_TRUNCATED_PAGE) { > - page_cache_release(page); > - continue; > - } > + if (unlikely(status)) > + goto fs_write_aop_error; > + I don't think this is correct, see how status >= 0 is used a few lines downwards. Perhaps something along the lines of an is_positive_aop_return() to test on? > if (likely(copied > 0)) { > if (!status) > status = copied; > @@ -1969,6 +1955,25 @@ generic_file_buffered_write(struct kiocb > break; > balance_dirty_pages_ratelimited(mapping); > cond_resched(); > + continue; > + > +fs_write_aop_error: > + if (status != AOP_TRUNCATED_PAGE) > + unlock_page(page); > + page_cache_release(page); > + > + /* > + * prepare_write() may have instantiated a few blocks > + * outside i_size. Trim these off again. Don't need > + * i_size_read because we hold i_mutex. > + */ > + if (pos + bytes > inode->i_size) > + vmtruncate(inode, inode->i_size); > + if (status == AOP_TRUNCATED_PAGE) > + continue; > + else > + break; > + > } while (count); > *ppos = pos; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2007-01-16 17:36 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-01-13 3:24 [patch 0/10] buffered write deadlock fix Nick Piggin 2007-01-13 3:24 ` Nick Piggin 2007-01-13 3:24 ` [patch 1/10] fs: libfs buffered write leak fix Nick Piggin 2007-01-13 3:24 ` Nick Piggin 2007-01-13 3:24 ` [patch 2/10] mm: revert "generic_file_buffered_write(): handle zero length iovec segments" Nick Piggin 2007-01-13 3:24 ` Nick Piggin, Andrew Morton 2007-01-13 3:24 ` [patch 3/10] mm: revert "generic_file_buffered_write(): deadlock on vectored write" Nick Piggin 2007-01-13 3:24 ` Nick Piggin, Andrew Morton 2007-01-13 3:24 ` [patch 4/10] mm: generic_file_buffered_write cleanup Nick Piggin 2007-01-13 3:24 ` Nick Piggin, Andrew Morton 2007-01-13 3:25 ` [patch 5/10] mm: debug write deadlocks Nick Piggin 2007-01-13 3:25 ` Nick Piggin 2007-01-13 3:25 ` [patch 6/10] mm: be sure to trim blocks Nick Piggin 2007-01-13 3:25 ` Nick Piggin 2007-01-14 14:25 ` Dmitriy Monakhov 2007-01-14 14:25 ` Dmitriy Monakhov 2007-01-20 3:50 ` Nick Piggin 2007-01-20 3:50 ` Nick Piggin 2007-01-16 17:36 ` Peter Zijlstra [this message] 2007-01-16 17:36 ` Peter Zijlstra 2007-01-16 19:14 ` Peter Zijlstra 2007-01-16 19:14 ` Peter Zijlstra 2007-01-20 3:52 ` Nick Piggin 2007-01-20 3:52 ` Nick Piggin 2007-01-13 3:25 ` [patch 7/10] mm: cleanup pagecache insertion operations Nick Piggin 2007-01-13 3:25 ` Nick Piggin 2007-01-13 3:25 ` [patch 8/10] mm: generic_file_buffered_write cleanup more Nick Piggin 2007-01-13 3:25 ` Nick Piggin 2007-01-13 3:25 ` [patch 9/10] mm: generic_file_buffered_write iovec cleanup Nick Piggin 2007-01-13 3:25 ` Nick Piggin 2007-01-13 3:25 ` [patch 10/10] mm: fix pagecache write deadlocks Nick Piggin 2007-01-13 3:25 ` Nick Piggin 2007-01-14 3:59 ` Nick Piggin 2007-01-14 3:59 ` Nick Piggin
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