* [PATCH] xfs: extent size hints can round up extents past MAXEXTLEN @ 2015-04-15 0:22 Dave Chinner 2015-04-15 21:18 ` Eric Sandeen 0 siblings, 1 reply; 3+ messages in thread From: Dave Chinner @ 2015-04-15 0:22 UTC (permalink / raw) To: xfs From: Dave Chinner <dchinner@redhat.com> This results in BMBT corruption, as seen by this test: # mkfs.xfs -f -d size=40051712b,agcount=4 /dev/vdc .... # mount /dev/vdc /mnt/scratch # xfs_io -ft -c "extsize 16m" -c "falloc 0 30g" -c "bmap -vp" /mnt/scratch/foo which results in this failure on a debug kernel: XFS: Assertion failed: (blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)) == 0, file: fs/xfs/libxfs/xfs_bmap_btree.c, line: 211 .... Call Trace: [<ffffffff814cf0ff>] xfs_bmbt_set_allf+0x8f/0x100 [<ffffffff814cf18d>] xfs_bmbt_set_all+0x1d/0x20 [<ffffffff814f2efe>] xfs_iext_insert+0x9e/0x120 [<ffffffff814c7956>] ? xfs_bmap_add_extent_hole_real+0x1c6/0xc70 [<ffffffff814c7956>] xfs_bmap_add_extent_hole_real+0x1c6/0xc70 [<ffffffff814caaab>] xfs_bmapi_write+0x72b/0xed0 [<ffffffff811c72ac>] ? kmem_cache_alloc+0x15c/0x170 [<ffffffff814fe070>] xfs_alloc_file_space+0x160/0x400 [<ffffffff81ddcc29>] ? down_write+0x29/0x60 [<ffffffff815063eb>] xfs_file_fallocate+0x29b/0x310 [<ffffffff811d2bc8>] ? __sb_start_write+0x58/0x120 [<ffffffff811e3e18>] ? do_vfs_ioctl+0x318/0x570 [<ffffffff811cd680>] vfs_fallocate+0x140/0x260 [<ffffffff811ce6f8>] SyS_fallocate+0x48/0x80 [<ffffffff81ddec09>] system_call_fastpath+0x12/0x17 The tracepoint that indicates the extent that triggered the assert failure is: xfs_iext_insert: idx 0 offset 0 block 16777224 count 2097152 flag 1 Clearly indicating that the extent length is greater than MAXEXTLEN, which is 2097151. A prior trace point shows the allocation was an exact size match and that a length greater than MAXEXTLEN was asked for: xfs_alloc_size_done: agno 1 agbno 8 minlen 2097152 maxlen 2097152 ^^^^^^^ ^^^^^^^ The issue is that the extent size hint alignment is rounding up the extent size past MAXEXTLEN, because xfs_bmapi_write() is not taking into account extent size hints when calculating the maximum extent length to allocate. xfs_bmapi_reserve_delalloc() is already doing this, but direct extent allocation is not. We don't see this problem with extent size hints through the IO path because we can't do single IOs large enough to trigger MAXEXTLEN allocation. fallocate(), OTOH, is not limited in it's allocation sizes and so needs help here. The fix is simply to copy the logic from xfs_bmapi_reserve_delalloc() and apply it apropriately to xfs_bmapi_write(). I also add an ASSERT() to xfs_bmap_extsize_align() so we'll catch cases of alignment exceeding MAXEXTLEN on debug kernel machines in future. Signed-off-by: Dave Chinner <dchinner@redhat.com> --- fs/xfs/libxfs/xfs_bmap.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index aeffeaa..e5aa8a6 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -3224,12 +3224,21 @@ xfs_bmap_extsize_align( align_alen += temp; align_off -= temp; } + + /* Same adjustment for the end of the requested area. */ + temp = (align_alen % extsz); + if (temp) + align_alen += extsz - temp; + /* - * Same adjustment for the end of the requested area. + * we are in trouble if the caller requested an extent that will align + * to something larger than the supported on disk extent size. Assert + * fail here to catch callers that make this mistake; they should always + * be setting the maximum allocation length to be (MAXEXTLEN - extsz) so + * we can round outwards here for alignment. */ - if ((temp = (align_alen % extsz))) { - align_alen += extsz - temp; - } + ASSERT(align_alen <= MAXEXTLEN); + /* * If the previous block overlaps with this proposed allocation * then move the start forward without adjusting the length. @@ -4287,7 +4296,19 @@ xfs_bmapi_allocate( &bma->prev); } } else { - bma->length = XFS_FILBLKS_MIN(bma->length, MAXEXTLEN); + /* Figure out the extent size, adjust alen */ + xfs_extlen_t maxlen = MAXEXTLEN; + xfs_extlen_t extsz = xfs_get_extsz_hint(bma->ip); + + /* + * Make sure we don't exceed a single extent length when we + * align the extent by reducing length we are going to allocate + * by the maximum amount extent size aligment may require. + */ + if (extsz) + maxlen -= (2 * extsz - 1); + + bma->length = XFS_FILBLKS_MIN(bma->length, maxlen); if (!bma->eof) bma->length = XFS_FILBLKS_MIN(bma->length, bma->got.br_startoff - bma->offset); -- 2.0.0 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] xfs: extent size hints can round up extents past MAXEXTLEN 2015-04-15 0:22 [PATCH] xfs: extent size hints can round up extents past MAXEXTLEN Dave Chinner @ 2015-04-15 21:18 ` Eric Sandeen 2015-04-15 23:00 ` Dave Chinner 0 siblings, 1 reply; 3+ messages in thread From: Eric Sandeen @ 2015-04-15 21:18 UTC (permalink / raw) To: Dave Chinner, xfs On 4/14/15 7:22 PM, Dave Chinner wrote: > From: Dave Chinner <dchinner@redhat.com> > > This results in BMBT corruption, as seen by this test: > > # mkfs.xfs -f -d size=40051712b,agcount=4 /dev/vdc > .... > # mount /dev/vdc /mnt/scratch > # xfs_io -ft -c "extsize 16m" -c "falloc 0 30g" -c "bmap -vp" /mnt/scratch/foo > > which results in this failure on a debug kernel: > > XFS: Assertion failed: (blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)) == 0, file: fs/xfs/libxfs/xfs_bmap_btree.c, line: 211 > .... > Call Trace: > [<ffffffff814cf0ff>] xfs_bmbt_set_allf+0x8f/0x100 > [<ffffffff814cf18d>] xfs_bmbt_set_all+0x1d/0x20 > [<ffffffff814f2efe>] xfs_iext_insert+0x9e/0x120 > [<ffffffff814c7956>] ? xfs_bmap_add_extent_hole_real+0x1c6/0xc70 > [<ffffffff814c7956>] xfs_bmap_add_extent_hole_real+0x1c6/0xc70 > [<ffffffff814caaab>] xfs_bmapi_write+0x72b/0xed0 > [<ffffffff811c72ac>] ? kmem_cache_alloc+0x15c/0x170 > [<ffffffff814fe070>] xfs_alloc_file_space+0x160/0x400 > [<ffffffff81ddcc29>] ? down_write+0x29/0x60 > [<ffffffff815063eb>] xfs_file_fallocate+0x29b/0x310 > [<ffffffff811d2bc8>] ? __sb_start_write+0x58/0x120 > [<ffffffff811e3e18>] ? do_vfs_ioctl+0x318/0x570 > [<ffffffff811cd680>] vfs_fallocate+0x140/0x260 > [<ffffffff811ce6f8>] SyS_fallocate+0x48/0x80 > [<ffffffff81ddec09>] system_call_fastpath+0x12/0x17 > > The tracepoint that indicates the extent that triggered the assert > failure is: > > xfs_iext_insert: idx 0 offset 0 block 16777224 count 2097152 flag 1 > > Clearly indicating that the extent length is greater than MAXEXTLEN, > which is 2097151. A prior trace point shows the allocation was an > exact size match and that a length greater than MAXEXTLEN was asked > for: > > xfs_alloc_size_done: agno 1 agbno 8 minlen 2097152 maxlen 2097152 > ^^^^^^^ ^^^^^^^ > > The issue is that the extent size hint alignment is rounding up the > extent size past MAXEXTLEN, because xfs_bmapi_write() is not taking > into account extent size hints when calculating the maximum extent > length to allocate. xfs_bmapi_reserve_delalloc() is already doing > this, but direct extent allocation is not. > > We don't see this problem with extent size hints through the IO path > because we can't do single IOs large enough to trigger MAXEXTLEN > allocation. fallocate(), OTOH, is not limited in it's allocation > sizes and so needs help here. The fix is simply to copy the logic > from xfs_bmapi_reserve_delalloc() and apply it apropriately to > xfs_bmapi_write(). Cool, thanks for sorting that out! > I also add an ASSERT() to xfs_bmap_extsize_align() so we'll catch > cases of alignment exceeding MAXEXTLEN on debug kernel machines in > future. > > Signed-off-by: Dave Chinner <dchinner@redhat.com> > --- > fs/xfs/libxfs/xfs_bmap.c | 31 ++++++++++++++++++++++++++----- > 1 file changed, 26 insertions(+), 5 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > index aeffeaa..e5aa8a6 100644 > --- a/fs/xfs/libxfs/xfs_bmap.c > +++ b/fs/xfs/libxfs/xfs_bmap.c > @@ -3224,12 +3224,21 @@ xfs_bmap_extsize_align( > align_alen += temp; > align_off -= temp; > } > + > + /* Same adjustment for the end of the requested area. */ > + temp = (align_alen % extsz); > + if (temp) > + align_alen += extsz - temp; > + > /* > - * Same adjustment for the end of the requested area. > + * we are in trouble if the caller requested an extent that will align > + * to something larger than the supported on disk extent size. Assert > + * fail here to catch callers that make this mistake; they should always > + * be setting the maximum allocation length to be (MAXEXTLEN - extsz) so > + * we can round outwards here for alignment. > */ > - if ((temp = (align_alen % extsz))) { > - align_alen += extsz - temp; > - } > + ASSERT(align_alen <= MAXEXTLEN); Hm, I was going to ask if we could return EINVAL w/ a warning printk, so that this doesn't silently corrupt on non-dbug kernels, but I see callers do things like: error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev, align, 0, ap->eof, 0, ap->conv, &ap->offset, &ap->length); ASSERT(!error); and nothing else with the error return, so... hohum. I think those callchains could be cleaned up to handle errors but ... outside the scope of this patch. > + > /* > * If the previous block overlaps with this proposed allocation > * then move the start forward without adjusting the length. > @@ -4287,7 +4296,19 @@ xfs_bmapi_allocate( > &bma->prev); > } > } else { > - bma->length = XFS_FILBLKS_MIN(bma->length, MAXEXTLEN); > + /* Figure out the extent size, adjust alen */ > + xfs_extlen_t maxlen = MAXEXTLEN; > + xfs_extlen_t extsz = xfs_get_extsz_hint(bma->ip); > + > + /* > + * Make sure we don't exceed a single extent length when we > + * align the extent by reducing length we are going to allocate > + * by the maximum amount extent size aligment may require. "alignment" (maybe fix the other comment too?) Or better yet, would this be possible to factor into a helper? /* * Make sure we don't exceed a single extent length when we * align the extent by reducing length we are going to * allocate by the maximum amount extent size aligment may * require. */ STATIC xfs_extlen_t xfs_max_extent_len( struct xfs_inode *ip) { xfs_extlen_t maxlen = MAXEXTLEN; xfs_extlen_t extsz = xfs_get_extsz_hint(ip); /* Insert comment about math here ;) */ if (extsz) maxlen -= (2 * extsz - 1); return maxlen; } ... bma->length = XFS_FILBLKS_MIN(bma->length, xfs_max_extent_len(ip)); ? > + */ > + if (extsz) > + maxlen -= (2 * extsz - 1); > + > + bma->length = XFS_FILBLKS_MIN(bma->length, maxlen); > if (!bma->eof) > bma->length = XFS_FILBLKS_MIN(bma->length, > bma->got.br_startoff - bma->offset); > _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] xfs: extent size hints can round up extents past MAXEXTLEN 2015-04-15 21:18 ` Eric Sandeen @ 2015-04-15 23:00 ` Dave Chinner 0 siblings, 0 replies; 3+ messages in thread From: Dave Chinner @ 2015-04-15 23:00 UTC (permalink / raw) To: Eric Sandeen; +Cc: xfs On Wed, Apr 15, 2015 at 04:18:28PM -0500, Eric Sandeen wrote: > On 4/14/15 7:22 PM, Dave Chinner wrote: > > From: Dave Chinner <dchinner@redhat.com> > > > > This results in BMBT corruption, as seen by this test: > > > > # mkfs.xfs -f -d size=40051712b,agcount=4 /dev/vdc > > .... > > # mount /dev/vdc /mnt/scratch > > # xfs_io -ft -c "extsize 16m" -c "falloc 0 30g" -c "bmap -vp" /mnt/scratch/foo > > > > which results in this failure on a debug kernel: > > > > XFS: Assertion failed: (blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)) == 0, file: fs/xfs/libxfs/xfs_bmap_btree.c, line: 211 > > .... > > Call Trace: > > [<ffffffff814cf0ff>] xfs_bmbt_set_allf+0x8f/0x100 > > [<ffffffff814cf18d>] xfs_bmbt_set_all+0x1d/0x20 > > [<ffffffff814f2efe>] xfs_iext_insert+0x9e/0x120 > > [<ffffffff814c7956>] ? xfs_bmap_add_extent_hole_real+0x1c6/0xc70 > > [<ffffffff814c7956>] xfs_bmap_add_extent_hole_real+0x1c6/0xc70 > > [<ffffffff814caaab>] xfs_bmapi_write+0x72b/0xed0 > > [<ffffffff811c72ac>] ? kmem_cache_alloc+0x15c/0x170 > > [<ffffffff814fe070>] xfs_alloc_file_space+0x160/0x400 > > [<ffffffff81ddcc29>] ? down_write+0x29/0x60 > > [<ffffffff815063eb>] xfs_file_fallocate+0x29b/0x310 > > [<ffffffff811d2bc8>] ? __sb_start_write+0x58/0x120 > > [<ffffffff811e3e18>] ? do_vfs_ioctl+0x318/0x570 > > [<ffffffff811cd680>] vfs_fallocate+0x140/0x260 > > [<ffffffff811ce6f8>] SyS_fallocate+0x48/0x80 > > [<ffffffff81ddec09>] system_call_fastpath+0x12/0x17 > > > > The tracepoint that indicates the extent that triggered the assert > > failure is: > > > > xfs_iext_insert: idx 0 offset 0 block 16777224 count 2097152 flag 1 > > > > Clearly indicating that the extent length is greater than MAXEXTLEN, > > which is 2097151. A prior trace point shows the allocation was an > > exact size match and that a length greater than MAXEXTLEN was asked > > for: > > > > xfs_alloc_size_done: agno 1 agbno 8 minlen 2097152 maxlen 2097152 > > ^^^^^^^ ^^^^^^^ > > > > The issue is that the extent size hint alignment is rounding up the > > extent size past MAXEXTLEN, because xfs_bmapi_write() is not taking > > into account extent size hints when calculating the maximum extent > > length to allocate. xfs_bmapi_reserve_delalloc() is already doing > > this, but direct extent allocation is not. > > > > We don't see this problem with extent size hints through the IO path > > because we can't do single IOs large enough to trigger MAXEXTLEN > > allocation. fallocate(), OTOH, is not limited in it's allocation > > sizes and so needs help here. The fix is simply to copy the logic > > from xfs_bmapi_reserve_delalloc() and apply it apropriately to > > xfs_bmapi_write(). > > Cool, thanks for sorting that out! .... > > @@ -4287,7 +4296,19 @@ xfs_bmapi_allocate( > > &bma->prev); > > } > > } else { > > - bma->length = XFS_FILBLKS_MIN(bma->length, MAXEXTLEN); > > + /* Figure out the extent size, adjust alen */ > > + xfs_extlen_t maxlen = MAXEXTLEN; > > + xfs_extlen_t extsz = xfs_get_extsz_hint(bma->ip); > > + > > + /* > > + * Make sure we don't exceed a single extent length when we > > + * align the extent by reducing length we are going to allocate > > + * by the maximum amount extent size aligment may require. > > "alignment" (maybe fix the other comment too?) > > Or better yet, would this be possible to factor into a helper? > > /* > * Make sure we don't exceed a single extent length when we > * align the extent by reducing length we are going to > * allocate by the maximum amount extent size aligment may > * require. > */ > STATIC xfs_extlen_t > xfs_max_extent_len( > struct xfs_inode *ip) > { > xfs_extlen_t maxlen = MAXEXTLEN; > xfs_extlen_t extsz = xfs_get_extsz_hint(ip); > > /* Insert comment about math here ;) */ > if (extsz) > maxlen -= (2 * extsz - 1); > > return maxlen; > } > > > ... > > bma->length = XFS_FILBLKS_MIN(bma->length, xfs_max_extent_len(ip)); I thought about that, then just sent the working patch ;) I'll refactor and send again. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2015-04-15 23:09 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2015-04-15 0:22 [PATCH] xfs: extent size hints can round up extents past MAXEXTLEN Dave Chinner 2015-04-15 21:18 ` Eric Sandeen 2015-04-15 23:00 ` Dave Chinner
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox