Path: csiph.com!1.us.feeder.erje.net!feeder.erje.net!2.eu.feeder.erje.net!news.in-chemnitz.de!news2.arglkargh.de!news.mixmin.net!aioe.org!news.servidellagleba.it!bofh.it!news.nic.it!robomod From: "Darrick J. Wong" Newsgroups: linux.kernel Subject: Re: [PATCH v3] xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files Date: Mon, 03 Apr 2017 19:20:02 +0200 Message-ID: References: X-Original-To: Calvin Owens MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 65 Organization: linux.* mail to news gateway X-Original-Cc: Brian Foster , linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Dave Chinner , kernel-team@fb.com, stable@vger.kernel.org X-Original-Date: Mon, 3 Apr 2017 10:15:31 -0700 X-Original-Message-ID: <20170403171531.GJ4864@birch.djwong.org> X-Original-References: <22a11e65fd5037498a78de61f3ed4dae466ad854.1489791330.git.calvinowens@fb.com> <19504ff40a16efff2e51d85388fce5be578edbc3.1489985397.git.calvinowens@fb.com> <20170321113932.GA58653@bfoster.bfoster> <20170331041800.ugi4wgmbqx44mbwa@Haydn> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1615432 On Thu, Mar 30, 2017 at 09:18:00PM -0700, Calvin Owens wrote: > When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will > round the file size up to the nearest multiple of PAGE_SIZE: > > calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1 > calvinow@vm-disks/generic-xfs-1 ~$ stat test > Size: 2048 Blocks: 8 IO Block: 4096 regular file > calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test > calvinow@vm-disks/generic-xfs-1 ~$ stat test > Size: 4096 Blocks: 8 IO Block: 4096 regular file > > Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced > xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers > don't enforce that [pos,offset) lies strictly on [0,i_size) when being > called from xfs_free_file_space(), so by "leaking" these ranges into > xfs_zero_range() we get this buggy behavior. > > Fix this by reintroducing the checks xfs_zero_remaining_bytes() did > against i_size at the bottom of xfs_free_file_space(). > > Reported-by: Aaron Gao > Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") > Cc: Christoph Hellwig > Cc: Brian Foster > Cc: # 4.8+ > Signed-off-by: Calvin Owens > --- > fs/xfs/xfs_bmap_util.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > index 8b75dce..828532c 100644 > --- a/fs/xfs/xfs_bmap_util.c > +++ b/fs/xfs/xfs_bmap_util.c > @@ -1311,8 +1311,16 @@ xfs_free_file_space( > /* > * Now that we've unmap all full blocks we'll have to zero out any > * partial block at the beginning and/or end. xfs_zero_range is > - * smart enough to skip any holes, including those we just created. > + * smart enough to skip any holes, including those we just created, > + * but we must take care not to zero beyond EOF and enlarge i_size. > */ > + > + if (offset >= XFS_ISIZE(ip)) > + return 0; > + > + if (offset + len > XFS_ISIZE(ip)) > + len = XFS_ISIZE(ip) - offset; > + I'll pick this up for 4.12. Reviewed-by: Darrick J. Wong --D > return xfs_zero_range(ip, offset, len, NULL); > } > > -- > 2.9.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html