| Message ID | 20170331041800.ugi4wgmbqx44mbwa@Haydn (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
Looks fine,
Reviewed-by: Christoph Hellwig <hch@lst.de>
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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 <gzh@fb.com> > Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") > Cc: Christoph Hellwig <hch@lst.de> > Cc: Brian Foster <bfoster@redhat.com> > Cc: <stable@vger.kernel.org> # 4.8+ > Signed-off-by: Calvin Owens <calvinowens@fb.com> > --- > 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 <darrick.wong@oracle.com> --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 -- 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
On Mon, Apr 03, 2017 at 10:15:31AM -0700, Darrick J. Wong wrote: > 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 <gzh@fb.com> > > Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") > > Cc: Christoph Hellwig <hch@lst.de> > > Cc: Brian Foster <bfoster@redhat.com> > > Cc: <stable@vger.kernel.org> # 4.8+ > > Signed-off-by: Calvin Owens <calvinowens@fb.com> > > --- > > 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. Bah, hit send too quickly. I'll pick this up for 4.12, unless anyone wants me to push this for -rc6? --D > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> > > --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 > -- > 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 -- 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
On Mon, Apr 03, 2017 at 10:18:12AM -0700, Darrick J. Wong wrote:
> I'll pick this up for 4.12, unless anyone wants me to push this for -rc6?
Yes, please do. This is a regression that corrupts user visible data.
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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; + return xfs_zero_range(ip, offset, len, NULL); }
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 <gzh@fb.com> Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") Cc: Christoph Hellwig <hch@lst.de> Cc: Brian Foster <bfoster@redhat.com> Cc: <stable@vger.kernel.org> # 4.8+ Signed-off-by: Calvin Owens <calvinowens@fb.com> --- fs/xfs/xfs_bmap_util.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)