| Message ID | 20191204163809.GP7335@magnolia (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | xfs: fix log reservation overflows when allocating large rt extents | expand |
On Wed, Dec 04, 2019 at 08:38:09AM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > Omar Sandoval reported that a 4G fallocate on the realtime device causes > filesystem shutdowns due to a log reservation overflow that happens when > we log the rtbitmap updates. Factor rtbitmap/rtsummary updates into the > the tr_write and tr_itruncate log reservation calculation. > > "The following reproducer results in a transaction log overrun warning > for me: > > mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb > mount -o rtdev=/dev/vdc /dev/vdb /mnt > fallocate -l 4G /mnt/foo > > Reported-by: Omar Sandoval <osandov@osandov.com> This one works, as well. Thanks! Reported-and-tested-by: Omar Sandoval <osandov@fb.com> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > --- > fs/xfs/libxfs/xfs_trans_resv.c | 96 ++++++++++++++++++++++++++++++++-------- > 1 file changed, 77 insertions(+), 19 deletions(-)
Ping? Omar confirms it fixes xfs for him, so all this needs now is a formal review... --D On Wed, Dec 04, 2019 at 08:38:09AM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > Omar Sandoval reported that a 4G fallocate on the realtime device causes > filesystem shutdowns due to a log reservation overflow that happens when > we log the rtbitmap updates. Factor rtbitmap/rtsummary updates into the > the tr_write and tr_itruncate log reservation calculation. > > "The following reproducer results in a transaction log overrun warning > for me: > > mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb > mount -o rtdev=/dev/vdc /dev/vdb /mnt > fallocate -l 4G /mnt/foo > > Reported-by: Omar Sandoval <osandov@osandov.com> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > --- > fs/xfs/libxfs/xfs_trans_resv.c | 96 ++++++++++++++++++++++++++++++++-------- > 1 file changed, 77 insertions(+), 19 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c > index c55cd9a3dec9..824073a839ac 100644 > --- a/fs/xfs/libxfs/xfs_trans_resv.c > +++ b/fs/xfs/libxfs/xfs_trans_resv.c > @@ -196,6 +196,24 @@ xfs_calc_inode_chunk_res( > return res; > } > > +/* > + * Per-extent log reservation for the btree changes involved in freeing or > + * allocating a realtime extent. We have to be able to log as many rtbitmap > + * blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents, > + * as well as the realtime summary block. > + */ > +unsigned int > +xfs_rtalloc_log_count( > + struct xfs_mount *mp, > + unsigned int num_ops) > +{ > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > + unsigned int rtbmp_bytes; > + > + rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY; > + return (howmany(rtbmp_bytes, blksz) + 1) * num_ops; > +} > + > /* > * Various log reservation values. > * > @@ -218,13 +236,21 @@ xfs_calc_inode_chunk_res( > > /* > * In a write transaction we can allocate a maximum of 2 > - * extents. This gives: > + * extents. This gives (t1): > * the inode getting the new extents: inode size > * the inode's bmap btree: max depth * block size > * the agfs of the ags from which the extents are allocated: 2 * sector > * the superblock free block counter: sector size > * the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size > - * And the bmap_finish transaction can free bmap blocks in a join: > + * Or, if we're writing to a realtime file (t2): > + * the inode getting the new extents: inode size > + * the inode's bmap btree: max depth * block size > + * the agfs of the ags from which the extents are allocated: 2 * sector > + * the superblock free block counter: sector size > + * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes > + * the realtime summary: 1 block > + * the allocation btrees: 2 trees * (2 * max depth - 1) * block size > + * And the bmap_finish transaction can free bmap blocks in a join (t3): > * the agfs of the ags containing the blocks: 2 * sector size > * the agfls of the ags containing the blocks: 2 * sector size > * the super block free block counter: sector size > @@ -234,40 +260,72 @@ STATIC uint > xfs_calc_write_reservation( > struct xfs_mount *mp) > { > - return XFS_DQUOT_LOGRES(mp) + > - max((xfs_calc_inode_res(mp, 1) + > + unsigned int t1, t2, t3; > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > + > + t1 = xfs_calc_inode_res(mp, 1) + > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), blksz) + > + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > + > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > + t2 = xfs_calc_inode_res(mp, 1) + > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), > - XFS_FSB_TO_B(mp, 1)) + > + blksz) + > xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > - XFS_FSB_TO_B(mp, 1))), > - (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > - XFS_FSB_TO_B(mp, 1)))); > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 1), blksz) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), blksz); > + } else { > + t2 = 0; > + } > + > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > + > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > } > > /* > - * In truncating a file we free up to two extents at once. We can modify: > + * In truncating a file we free up to two extents at once. We can modify (t1): > * the inode being truncated: inode size > * the inode's bmap btree: (max depth + 1) * block size > - * And the bmap_finish transaction can free the blocks and bmap blocks: > + * And the bmap_finish transaction can free the blocks and bmap blocks (t2): > * the agf for each of the ags: 4 * sector size > * the agfl for each of the ags: 4 * sector size > * the super block to reflect the freed blocks: sector size > * worst case split in allocation btrees per extent assuming 4 extents: > * 4 exts * 2 trees * (2 * max depth - 1) * block size > + * Or, if it's a realtime file (t3): > + * the agf for each of the ags: 2 * sector size > + * the agfl for each of the ags: 2 * sector size > + * the super block to reflect the freed blocks: sector size > + * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes > + * the realtime summary: 2 exts * 1 block > + * worst case split in allocation btrees per extent assuming 2 extents: > + * 2 exts * 2 trees * (2 * max depth - 1) * block size > */ > STATIC uint > xfs_calc_itruncate_reservation( > struct xfs_mount *mp) > { > - return XFS_DQUOT_LOGRES(mp) + > - max((xfs_calc_inode_res(mp, 1) + > - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, > - XFS_FSB_TO_B(mp, 1))), > - (xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), > - XFS_FSB_TO_B(mp, 1)))); > + unsigned int t1, t2, t3; > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > + > + t1 = xfs_calc_inode_res(mp, 1) + > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); > + > + t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), blksz); > + > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > + } else { > + t3 = 0; > + } > + > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > } > > /*
On Wed, Dec 04, 2019 at 08:38:09AM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > Omar Sandoval reported that a 4G fallocate on the realtime device causes > filesystem shutdowns due to a log reservation overflow that happens when > we log the rtbitmap updates. Factor rtbitmap/rtsummary updates into the > the tr_write and tr_itruncate log reservation calculation. > > "The following reproducer results in a transaction log overrun warning > for me: > > mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb > mount -o rtdev=/dev/vdc /dev/vdb /mnt > fallocate -l 4G /mnt/foo > > Reported-by: Omar Sandoval <osandov@osandov.com> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > --- Looks reasonable enough given my limited knowledge on the rt bits. One question.. > fs/xfs/libxfs/xfs_trans_resv.c | 96 ++++++++++++++++++++++++++++++++-------- > 1 file changed, 77 insertions(+), 19 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c > index c55cd9a3dec9..824073a839ac 100644 > --- a/fs/xfs/libxfs/xfs_trans_resv.c > +++ b/fs/xfs/libxfs/xfs_trans_resv.c > @@ -196,6 +196,24 @@ xfs_calc_inode_chunk_res( > return res; > } > > +/* > + * Per-extent log reservation for the btree changes involved in freeing or > + * allocating a realtime extent. We have to be able to log as many rtbitmap > + * blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents, > + * as well as the realtime summary block. > + */ > +unsigned int > +xfs_rtalloc_log_count( > + struct xfs_mount *mp, > + unsigned int num_ops) > +{ > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > + unsigned int rtbmp_bytes; > + > + rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY; > + return (howmany(rtbmp_bytes, blksz) + 1) * num_ops; > +} > + > /* > * Various log reservation values. > * > @@ -218,13 +236,21 @@ xfs_calc_inode_chunk_res( > > /* > * In a write transaction we can allocate a maximum of 2 > - * extents. This gives: > + * extents. This gives (t1): > * the inode getting the new extents: inode size > * the inode's bmap btree: max depth * block size > * the agfs of the ags from which the extents are allocated: 2 * sector > * the superblock free block counter: sector size > * the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size > - * And the bmap_finish transaction can free bmap blocks in a join: > + * Or, if we're writing to a realtime file (t2): > + * the inode getting the new extents: inode size > + * the inode's bmap btree: max depth * block size > + * the agfs of the ags from which the extents are allocated: 2 * sector > + * the superblock free block counter: sector size > + * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes > + * the realtime summary: 1 block > + * the allocation btrees: 2 trees * (2 * max depth - 1) * block size Why do we include the allocation btrees in the rt reservations? I thought that we'd either allocate (or free) out of one pool or the other. Do we operate on both sets of structures in the same transaction? Brian > + * And the bmap_finish transaction can free bmap blocks in a join (t3): > * the agfs of the ags containing the blocks: 2 * sector size > * the agfls of the ags containing the blocks: 2 * sector size > * the super block free block counter: sector size > @@ -234,40 +260,72 @@ STATIC uint > xfs_calc_write_reservation( > struct xfs_mount *mp) > { > - return XFS_DQUOT_LOGRES(mp) + > - max((xfs_calc_inode_res(mp, 1) + > + unsigned int t1, t2, t3; > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > + > + t1 = xfs_calc_inode_res(mp, 1) + > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), blksz) + > + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > + > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > + t2 = xfs_calc_inode_res(mp, 1) + > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), > - XFS_FSB_TO_B(mp, 1)) + > + blksz) + > xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > - XFS_FSB_TO_B(mp, 1))), > - (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > - XFS_FSB_TO_B(mp, 1)))); > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 1), blksz) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), blksz); > + } else { > + t2 = 0; > + } > + > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > + > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > } > > /* > - * In truncating a file we free up to two extents at once. We can modify: > + * In truncating a file we free up to two extents at once. We can modify (t1): > * the inode being truncated: inode size > * the inode's bmap btree: (max depth + 1) * block size > - * And the bmap_finish transaction can free the blocks and bmap blocks: > + * And the bmap_finish transaction can free the blocks and bmap blocks (t2): > * the agf for each of the ags: 4 * sector size > * the agfl for each of the ags: 4 * sector size > * the super block to reflect the freed blocks: sector size > * worst case split in allocation btrees per extent assuming 4 extents: > * 4 exts * 2 trees * (2 * max depth - 1) * block size > + * Or, if it's a realtime file (t3): > + * the agf for each of the ags: 2 * sector size > + * the agfl for each of the ags: 2 * sector size > + * the super block to reflect the freed blocks: sector size > + * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes > + * the realtime summary: 2 exts * 1 block > + * worst case split in allocation btrees per extent assuming 2 extents: > + * 2 exts * 2 trees * (2 * max depth - 1) * block size > */ > STATIC uint > xfs_calc_itruncate_reservation( > struct xfs_mount *mp) > { > - return XFS_DQUOT_LOGRES(mp) + > - max((xfs_calc_inode_res(mp, 1) + > - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, > - XFS_FSB_TO_B(mp, 1))), > - (xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), > - XFS_FSB_TO_B(mp, 1)))); > + unsigned int t1, t2, t3; > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > + > + t1 = xfs_calc_inode_res(mp, 1) + > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); > + > + t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), blksz); > + > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > + } else { > + t3 = 0; > + } > + > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > } > > /* >
On Fri, Dec 13, 2019 at 07:18:40AM -0500, Brian Foster wrote: > On Wed, Dec 04, 2019 at 08:38:09AM -0800, Darrick J. Wong wrote: > > From: Darrick J. Wong <darrick.wong@oracle.com> > > > > Omar Sandoval reported that a 4G fallocate on the realtime device causes > > filesystem shutdowns due to a log reservation overflow that happens when > > we log the rtbitmap updates. Factor rtbitmap/rtsummary updates into the > > the tr_write and tr_itruncate log reservation calculation. > > > > "The following reproducer results in a transaction log overrun warning > > for me: > > > > mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb > > mount -o rtdev=/dev/vdc /dev/vdb /mnt > > fallocate -l 4G /mnt/foo > > > > Reported-by: Omar Sandoval <osandov@osandov.com> > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > > --- > > Looks reasonable enough given my limited knowledge on the rt bits. One > question.. > > > fs/xfs/libxfs/xfs_trans_resv.c | 96 ++++++++++++++++++++++++++++++++-------- > > 1 file changed, 77 insertions(+), 19 deletions(-) > > > > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c > > index c55cd9a3dec9..824073a839ac 100644 > > --- a/fs/xfs/libxfs/xfs_trans_resv.c > > +++ b/fs/xfs/libxfs/xfs_trans_resv.c > > @@ -196,6 +196,24 @@ xfs_calc_inode_chunk_res( > > return res; > > } > > > > +/* > > + * Per-extent log reservation for the btree changes involved in freeing or > > + * allocating a realtime extent. We have to be able to log as many rtbitmap > > + * blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents, > > + * as well as the realtime summary block. > > + */ > > +unsigned int > > +xfs_rtalloc_log_count( > > + struct xfs_mount *mp, > > + unsigned int num_ops) > > +{ > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > + unsigned int rtbmp_bytes; > > + > > + rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY; > > + return (howmany(rtbmp_bytes, blksz) + 1) * num_ops; > > +} > > + > > /* > > * Various log reservation values. > > * > > @@ -218,13 +236,21 @@ xfs_calc_inode_chunk_res( > > > > /* > > * In a write transaction we can allocate a maximum of 2 > > - * extents. This gives: > > + * extents. This gives (t1): > > * the inode getting the new extents: inode size > > * the inode's bmap btree: max depth * block size > > * the agfs of the ags from which the extents are allocated: 2 * sector > > * the superblock free block counter: sector size > > * the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size > > - * And the bmap_finish transaction can free bmap blocks in a join: > > + * Or, if we're writing to a realtime file (t2): > > + * the inode getting the new extents: inode size > > + * the inode's bmap btree: max depth * block size > > + * the agfs of the ags from which the extents are allocated: 2 * sector > > + * the superblock free block counter: sector size > > + * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes > > + * the realtime summary: 1 block > > + * the allocation btrees: 2 trees * (2 * max depth - 1) * block size > > Why do we include the allocation btrees in the rt reservations? I > thought that we'd either allocate (or free) out of one pool or the > other. Do we operate on both sets of structures in the same transaction? I read "allocation btrees: 2 exts * 2 trees..." for t1 to mean that we need to be able to allocate one datadev extent (which could cause a full bnobt/cntbt split) for the actual file data, and then the second extent is to handle allocating a new bmbt block to the bmap btree. Based on that, I concluded that we still need to reserve space for that "second" extent to handle allocating a new bmbt block (on the datadev). While pondering that, I wondered if even that's really true because what happens if you suffer a full bmbt split, the free space is so fragmented that each level of the bmbt split ends up allocating a new block from a different part of the free space btrees and that in turn causes splits in the free space btrees? I think the answer is "no we're fine" because even if each new bmbt block comes from a different bnobt record, a full bmbt split will never hollow out more than half of one bnobt block's worth of free space records. --D > Brian > > > + * And the bmap_finish transaction can free bmap blocks in a join (t3): > > * the agfs of the ags containing the blocks: 2 * sector size > > * the agfls of the ags containing the blocks: 2 * sector size > > * the super block free block counter: sector size > > @@ -234,40 +260,72 @@ STATIC uint > > xfs_calc_write_reservation( > > struct xfs_mount *mp) > > { > > - return XFS_DQUOT_LOGRES(mp) + > > - max((xfs_calc_inode_res(mp, 1) + > > + unsigned int t1, t2, t3; > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > + > > + t1 = xfs_calc_inode_res(mp, 1) + > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), blksz) + > > + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > + > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > + t2 = xfs_calc_inode_res(mp, 1) + > > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), > > - XFS_FSB_TO_B(mp, 1)) + > > + blksz) + > > xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > - XFS_FSB_TO_B(mp, 1))), > > - (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > - XFS_FSB_TO_B(mp, 1)))); > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 1), blksz) + > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), blksz); > > + } else { > > + t2 = 0; > > + } > > + > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > + > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > } > > > > /* > > - * In truncating a file we free up to two extents at once. We can modify: > > + * In truncating a file we free up to two extents at once. We can modify (t1): > > * the inode being truncated: inode size > > * the inode's bmap btree: (max depth + 1) * block size > > - * And the bmap_finish transaction can free the blocks and bmap blocks: > > + * And the bmap_finish transaction can free the blocks and bmap blocks (t2): > > * the agf for each of the ags: 4 * sector size > > * the agfl for each of the ags: 4 * sector size > > * the super block to reflect the freed blocks: sector size > > * worst case split in allocation btrees per extent assuming 4 extents: > > * 4 exts * 2 trees * (2 * max depth - 1) * block size > > + * Or, if it's a realtime file (t3): > > + * the agf for each of the ags: 2 * sector size > > + * the agfl for each of the ags: 2 * sector size > > + * the super block to reflect the freed blocks: sector size > > + * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes > > + * the realtime summary: 2 exts * 1 block > > + * worst case split in allocation btrees per extent assuming 2 extents: > > + * 2 exts * 2 trees * (2 * max depth - 1) * block size > > */ > > STATIC uint > > xfs_calc_itruncate_reservation( > > struct xfs_mount *mp) > > { > > - return XFS_DQUOT_LOGRES(mp) + > > - max((xfs_calc_inode_res(mp, 1) + > > - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, > > - XFS_FSB_TO_B(mp, 1))), > > - (xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), > > - XFS_FSB_TO_B(mp, 1)))); > > + unsigned int t1, t2, t3; > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > + > > + t1 = xfs_calc_inode_res(mp, 1) + > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); > > + > > + t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), blksz); > > + > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > + } else { > > + t3 = 0; > > + } > > + > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > } > > > > /* > > >
On Fri, Dec 13, 2019 at 12:19:57PM -0800, Darrick J. Wong wrote: > On Fri, Dec 13, 2019 at 07:18:40AM -0500, Brian Foster wrote: > > On Wed, Dec 04, 2019 at 08:38:09AM -0800, Darrick J. Wong wrote: > > > From: Darrick J. Wong <darrick.wong@oracle.com> > > > > > > Omar Sandoval reported that a 4G fallocate on the realtime device causes > > > filesystem shutdowns due to a log reservation overflow that happens when > > > we log the rtbitmap updates. Factor rtbitmap/rtsummary updates into the > > > the tr_write and tr_itruncate log reservation calculation. > > > > > > "The following reproducer results in a transaction log overrun warning > > > for me: > > > > > > mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb > > > mount -o rtdev=/dev/vdc /dev/vdb /mnt > > > fallocate -l 4G /mnt/foo > > > > > > Reported-by: Omar Sandoval <osandov@osandov.com> > > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > > > --- > > > > Looks reasonable enough given my limited knowledge on the rt bits. One > > question.. > > > > > fs/xfs/libxfs/xfs_trans_resv.c | 96 ++++++++++++++++++++++++++++++++-------- > > > 1 file changed, 77 insertions(+), 19 deletions(-) > > > > > > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c > > > index c55cd9a3dec9..824073a839ac 100644 > > > --- a/fs/xfs/libxfs/xfs_trans_resv.c > > > +++ b/fs/xfs/libxfs/xfs_trans_resv.c > > > @@ -196,6 +196,24 @@ xfs_calc_inode_chunk_res( > > > return res; > > > } > > > > > > +/* > > > + * Per-extent log reservation for the btree changes involved in freeing or > > > + * allocating a realtime extent. We have to be able to log as many rtbitmap > > > + * blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents, > > > + * as well as the realtime summary block. > > > + */ > > > +unsigned int > > > +xfs_rtalloc_log_count( > > > + struct xfs_mount *mp, > > > + unsigned int num_ops) > > > +{ > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > + unsigned int rtbmp_bytes; > > > + > > > + rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY; > > > + return (howmany(rtbmp_bytes, blksz) + 1) * num_ops; > > > +} > > > + > > > /* > > > * Various log reservation values. > > > * > > > @@ -218,13 +236,21 @@ xfs_calc_inode_chunk_res( > > > > > > /* > > > * In a write transaction we can allocate a maximum of 2 > > > - * extents. This gives: > > > + * extents. This gives (t1): > > > * the inode getting the new extents: inode size > > > * the inode's bmap btree: max depth * block size > > > * the agfs of the ags from which the extents are allocated: 2 * sector > > > * the superblock free block counter: sector size > > > * the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size > > > - * And the bmap_finish transaction can free bmap blocks in a join: > > > + * Or, if we're writing to a realtime file (t2): > > > + * the inode getting the new extents: inode size > > > + * the inode's bmap btree: max depth * block size > > > + * the agfs of the ags from which the extents are allocated: 2 * sector > > > + * the superblock free block counter: sector size > > > + * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes > > > + * the realtime summary: 1 block > > > + * the allocation btrees: 2 trees * (2 * max depth - 1) * block size > > > > Why do we include the allocation btrees in the rt reservations? I > > thought that we'd either allocate (or free) out of one pool or the > > other. Do we operate on both sets of structures in the same transaction? > > I read "allocation btrees: 2 exts * 2 trees..." for t1 to mean that we > need to be able to allocate one datadev extent (which could cause a full > bnobt/cntbt split) for the actual file data, and then the second extent is > to handle allocating a new bmbt block to the bmap btree. > Ah, metadata out of the traditional trees.. that makes sense. My general understanding is that we have two sets of free space and thus two associated free space tracking structures: the traditional perag btrees for the local device and some bitmap indexing scheme for the external realtime device. Based on that, it looks like a file data allocation falls down into xfs_bmap_rtalloc() to allocate data blocks via the RT subsystem and the subsequent bmap update falls into the bmapbt code that uses xfs_alloc_vextent() directly to allocate blocks for the bmbt. With regard to the 2 extents, the first sentence in the comment above suggests to me that the two extents is a per-transaction operational limit. IOW, a write transaction supports two xfs_bmapi_write() calls, for example, as opposed to referring to the two lower level allocations outlined above. That seems consistent with the "2 * sector" AGF portion of the reservation as well, but I could easily be wrong about that. BTW I'm not following what you mean by a datadev extent causing a bnobt/cntbt split. Doesn't the data extent come from the RT free space, or are you just indirectly referring to the supporting bmbt block allocation causing a split..? > Based on that, I concluded that we still need to reserve space for that > "second" extent to handle allocating a new bmbt block (on the datadev). > > While pondering that, I wondered if even that's really true because what > happens if you suffer a full bmbt split, the free space is so fragmented > that each level of the bmbt split ends up allocating a new block from a > different part of the free space btrees and that in turn causes splits > in the free space btrees? > > I think the answer is "no we're fine" because even if each new bmbt > block comes from a different bnobt record, a full bmbt split will never > hollow out more than half of one bnobt block's worth of free space > records. > Yeah. I couldn't say for sure, but this strikes me as something we'd see reports of if it were possible/likely to occur in practice, particularly since this is the basis of how the allocation transaction reservations are calculated in general (not just for RT). Brian > --D > > > Brian > > > > > + * And the bmap_finish transaction can free bmap blocks in a join (t3): > > > * the agfs of the ags containing the blocks: 2 * sector size > > > * the agfls of the ags containing the blocks: 2 * sector size > > > * the super block free block counter: sector size > > > @@ -234,40 +260,72 @@ STATIC uint > > > xfs_calc_write_reservation( > > > struct xfs_mount *mp) > > > { > > > - return XFS_DQUOT_LOGRES(mp) + > > > - max((xfs_calc_inode_res(mp, 1) + > > > + unsigned int t1, t2, t3; > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > + > > > + t1 = xfs_calc_inode_res(mp, 1) + > > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), blksz) + > > > + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > + > > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > > + t2 = xfs_calc_inode_res(mp, 1) + > > > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), > > > - XFS_FSB_TO_B(mp, 1)) + > > > + blksz) + > > > xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > > - XFS_FSB_TO_B(mp, 1))), > > > - (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > > - XFS_FSB_TO_B(mp, 1)))); > > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 1), blksz) + > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), blksz); > > > + } else { > > > + t2 = 0; > > > + } > > > + > > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > + > > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > > } > > > > > > /* > > > - * In truncating a file we free up to two extents at once. We can modify: > > > + * In truncating a file we free up to two extents at once. We can modify (t1): > > > * the inode being truncated: inode size > > > * the inode's bmap btree: (max depth + 1) * block size > > > - * And the bmap_finish transaction can free the blocks and bmap blocks: > > > + * And the bmap_finish transaction can free the blocks and bmap blocks (t2): > > > * the agf for each of the ags: 4 * sector size > > > * the agfl for each of the ags: 4 * sector size > > > * the super block to reflect the freed blocks: sector size > > > * worst case split in allocation btrees per extent assuming 4 extents: > > > * 4 exts * 2 trees * (2 * max depth - 1) * block size > > > + * Or, if it's a realtime file (t3): > > > + * the agf for each of the ags: 2 * sector size > > > + * the agfl for each of the ags: 2 * sector size > > > + * the super block to reflect the freed blocks: sector size > > > + * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes > > > + * the realtime summary: 2 exts * 1 block > > > + * worst case split in allocation btrees per extent assuming 2 extents: > > > + * 2 exts * 2 trees * (2 * max depth - 1) * block size > > > */ > > > STATIC uint > > > xfs_calc_itruncate_reservation( > > > struct xfs_mount *mp) > > > { > > > - return XFS_DQUOT_LOGRES(mp) + > > > - max((xfs_calc_inode_res(mp, 1) + > > > - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, > > > - XFS_FSB_TO_B(mp, 1))), > > > - (xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), > > > - XFS_FSB_TO_B(mp, 1)))); > > > + unsigned int t1, t2, t3; > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > + > > > + t1 = xfs_calc_inode_res(mp, 1) + > > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); > > > + > > > + t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), blksz); > > > + > > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > + } else { > > > + t3 = 0; > > > + } > > > + > > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > > } > > > > > > /* > > > > > >
On Mon, Dec 16, 2019 at 07:23:32AM -0500, Brian Foster wrote: > On Fri, Dec 13, 2019 at 12:19:57PM -0800, Darrick J. Wong wrote: > > On Fri, Dec 13, 2019 at 07:18:40AM -0500, Brian Foster wrote: > > > On Wed, Dec 04, 2019 at 08:38:09AM -0800, Darrick J. Wong wrote: > > > > From: Darrick J. Wong <darrick.wong@oracle.com> > > > > > > > > Omar Sandoval reported that a 4G fallocate on the realtime device causes > > > > filesystem shutdowns due to a log reservation overflow that happens when > > > > we log the rtbitmap updates. Factor rtbitmap/rtsummary updates into the > > > > the tr_write and tr_itruncate log reservation calculation. > > > > > > > > "The following reproducer results in a transaction log overrun warning > > > > for me: > > > > > > > > mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb > > > > mount -o rtdev=/dev/vdc /dev/vdb /mnt > > > > fallocate -l 4G /mnt/foo > > > > > > > > Reported-by: Omar Sandoval <osandov@osandov.com> > > > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > > > > --- > > > > > > Looks reasonable enough given my limited knowledge on the rt bits. One > > > question.. > > > > > > > fs/xfs/libxfs/xfs_trans_resv.c | 96 ++++++++++++++++++++++++++++++++-------- > > > > 1 file changed, 77 insertions(+), 19 deletions(-) > > > > > > > > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c > > > > index c55cd9a3dec9..824073a839ac 100644 > > > > --- a/fs/xfs/libxfs/xfs_trans_resv.c > > > > +++ b/fs/xfs/libxfs/xfs_trans_resv.c > > > > @@ -196,6 +196,24 @@ xfs_calc_inode_chunk_res( > > > > return res; > > > > } > > > > > > > > +/* > > > > + * Per-extent log reservation for the btree changes involved in freeing or > > > > + * allocating a realtime extent. We have to be able to log as many rtbitmap > > > > + * blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents, > > > > + * as well as the realtime summary block. > > > > + */ > > > > +unsigned int > > > > +xfs_rtalloc_log_count( > > > > + struct xfs_mount *mp, > > > > + unsigned int num_ops) > > > > +{ > > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > > + unsigned int rtbmp_bytes; > > > > + > > > > + rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY; > > > > + return (howmany(rtbmp_bytes, blksz) + 1) * num_ops; > > > > +} > > > > + > > > > /* > > > > * Various log reservation values. > > > > * > > > > @@ -218,13 +236,21 @@ xfs_calc_inode_chunk_res( > > > > > > > > /* > > > > * In a write transaction we can allocate a maximum of 2 > > > > - * extents. This gives: > > > > + * extents. This gives (t1): > > > > * the inode getting the new extents: inode size > > > > * the inode's bmap btree: max depth * block size > > > > * the agfs of the ags from which the extents are allocated: 2 * sector > > > > * the superblock free block counter: sector size > > > > * the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size > > > > - * And the bmap_finish transaction can free bmap blocks in a join: > > > > + * Or, if we're writing to a realtime file (t2): > > > > + * the inode getting the new extents: inode size > > > > + * the inode's bmap btree: max depth * block size > > > > + * the agfs of the ags from which the extents are allocated: 2 * sector > > > > + * the superblock free block counter: sector size > > > > + * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes > > > > + * the realtime summary: 1 block > > > > + * the allocation btrees: 2 trees * (2 * max depth - 1) * block size > > > > > > Why do we include the allocation btrees in the rt reservations? I > > > thought that we'd either allocate (or free) out of one pool or the > > > other. Do we operate on both sets of structures in the same transaction? > > > > I read "allocation btrees: 2 exts * 2 trees..." for t1 to mean that we > > need to be able to allocate one datadev extent (which could cause a full > > bnobt/cntbt split) for the actual file data, and then the second extent is > > to handle allocating a new bmbt block to the bmap btree. > > > > Ah, metadata out of the traditional trees.. that makes sense. My general > understanding is that we have two sets of free space and thus two > associated free space tracking structures: the traditional perag btrees > for the local device and some bitmap indexing scheme for the external > realtime device. Based on that, it looks like a file data allocation > falls down into xfs_bmap_rtalloc() to allocate data blocks via the RT > subsystem and the subsequent bmap update falls into the bmapbt code that > uses xfs_alloc_vextent() directly to allocate blocks for the bmbt. > > With regard to the 2 extents, the first sentence in the comment above > suggests to me that the two extents is a per-transaction operational > limit. IOW, a write transaction supports two xfs_bmapi_write() calls, > for example, as opposed to referring to the two lower level allocations > outlined above. That seems consistent with the "2 * sector" AGF portion > of the reservation as well, but I could easily be wrong about that. > > BTW I'm not following what you mean by a datadev extent causing a > bnobt/cntbt split. Doesn't the data extent come from the RT free space, > or are you just indirectly referring to the supporting bmbt block > allocation causing a split..? "t1" is reflects writes to regular files on the datadev device, so "allocate one datadev extent (which could cause a full bnobt/cntbt split) for actual file data" applies to that case, not t2. "t2" is for writes to realtime files on the rt device. > > Based on that, I concluded that we still need to reserve space for that > > "second" extent to handle allocating a new bmbt block (on the datadev). Perhaps my reply could have been clearer had I said: "Based on that, I concluded for the realtime case (t2) that we still..." > > While pondering that, I wondered if even that's really true because what > > happens if you suffer a full bmbt split, the free space is so fragmented > > that each level of the bmbt split ends up allocating a new block from a > > different part of the free space btrees and that in turn causes splits > > in the free space btrees? > > > > I think the answer is "no we're fine" because even if each new bmbt > > block comes from a different bnobt record, a full bmbt split will never > > hollow out more than half of one bnobt block's worth of free space > > records. > > > > Yeah. I couldn't say for sure, but this strikes me as something we'd see > reports of if it were possible/likely to occur in practice, particularly > since this is the basis of how the allocation transaction reservations > are calculated in general (not just for RT). <nod> --D > Brian > > > --D > > > > > Brian > > > > > > > + * And the bmap_finish transaction can free bmap blocks in a join (t3): > > > > * the agfs of the ags containing the blocks: 2 * sector size > > > > * the agfls of the ags containing the blocks: 2 * sector size > > > > * the super block free block counter: sector size > > > > @@ -234,40 +260,72 @@ STATIC uint > > > > xfs_calc_write_reservation( > > > > struct xfs_mount *mp) > > > > { > > > > - return XFS_DQUOT_LOGRES(mp) + > > > > - max((xfs_calc_inode_res(mp, 1) + > > > > + unsigned int t1, t2, t3; > > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > > + > > > > + t1 = xfs_calc_inode_res(mp, 1) + > > > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), blksz) + > > > > + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > > + > > > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > > > + t2 = xfs_calc_inode_res(mp, 1) + > > > > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), > > > > - XFS_FSB_TO_B(mp, 1)) + > > > > + blksz) + > > > > xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > > > - XFS_FSB_TO_B(mp, 1))), > > > > - (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > > > - XFS_FSB_TO_B(mp, 1)))); > > > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 1), blksz) + > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), blksz); > > > > + } else { > > > > + t2 = 0; > > > > + } > > > > + > > > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > > + > > > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > > > } > > > > > > > > /* > > > > - * In truncating a file we free up to two extents at once. We can modify: > > > > + * In truncating a file we free up to two extents at once. We can modify (t1): > > > > * the inode being truncated: inode size > > > > * the inode's bmap btree: (max depth + 1) * block size > > > > - * And the bmap_finish transaction can free the blocks and bmap blocks: > > > > + * And the bmap_finish transaction can free the blocks and bmap blocks (t2): > > > > * the agf for each of the ags: 4 * sector size > > > > * the agfl for each of the ags: 4 * sector size > > > > * the super block to reflect the freed blocks: sector size > > > > * worst case split in allocation btrees per extent assuming 4 extents: > > > > * 4 exts * 2 trees * (2 * max depth - 1) * block size > > > > + * Or, if it's a realtime file (t3): > > > > + * the agf for each of the ags: 2 * sector size > > > > + * the agfl for each of the ags: 2 * sector size > > > > + * the super block to reflect the freed blocks: sector size > > > > + * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes > > > > + * the realtime summary: 2 exts * 1 block > > > > + * worst case split in allocation btrees per extent assuming 2 extents: > > > > + * 2 exts * 2 trees * (2 * max depth - 1) * block size > > > > */ > > > > STATIC uint > > > > xfs_calc_itruncate_reservation( > > > > struct xfs_mount *mp) > > > > { > > > > - return XFS_DQUOT_LOGRES(mp) + > > > > - max((xfs_calc_inode_res(mp, 1) + > > > > - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, > > > > - XFS_FSB_TO_B(mp, 1))), > > > > - (xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), > > > > - XFS_FSB_TO_B(mp, 1)))); > > > > + unsigned int t1, t2, t3; > > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > > + > > > > + t1 = xfs_calc_inode_res(mp, 1) + > > > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); > > > > + > > > > + t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), blksz); > > > > + > > > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > > + } else { > > > > + t3 = 0; > > > > + } > > > > + > > > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > > > } > > > > > > > > /* > > > > > > > > > >
On Mon, Dec 16, 2019 at 08:47:45AM -0800, Darrick J. Wong wrote: > On Mon, Dec 16, 2019 at 07:23:32AM -0500, Brian Foster wrote: > > On Fri, Dec 13, 2019 at 12:19:57PM -0800, Darrick J. Wong wrote: > > > On Fri, Dec 13, 2019 at 07:18:40AM -0500, Brian Foster wrote: > > > > On Wed, Dec 04, 2019 at 08:38:09AM -0800, Darrick J. Wong wrote: > > > > > From: Darrick J. Wong <darrick.wong@oracle.com> > > > > > > > > > > Omar Sandoval reported that a 4G fallocate on the realtime device causes > > > > > filesystem shutdowns due to a log reservation overflow that happens when > > > > > we log the rtbitmap updates. Factor rtbitmap/rtsummary updates into the > > > > > the tr_write and tr_itruncate log reservation calculation. > > > > > > > > > > "The following reproducer results in a transaction log overrun warning > > > > > for me: > > > > > > > > > > mkfs.xfs -f -r rtdev=/dev/vdc -d rtinherit=1 -m reflink=0 /dev/vdb > > > > > mount -o rtdev=/dev/vdc /dev/vdb /mnt > > > > > fallocate -l 4G /mnt/foo > > > > > > > > > > Reported-by: Omar Sandoval <osandov@osandov.com> > > > > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > > > > > --- > > > > > > > > Looks reasonable enough given my limited knowledge on the rt bits. One > > > > question.. > > > > > > > > > fs/xfs/libxfs/xfs_trans_resv.c | 96 ++++++++++++++++++++++++++++++++-------- > > > > > 1 file changed, 77 insertions(+), 19 deletions(-) > > > > > > > > > > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c > > > > > index c55cd9a3dec9..824073a839ac 100644 > > > > > --- a/fs/xfs/libxfs/xfs_trans_resv.c > > > > > +++ b/fs/xfs/libxfs/xfs_trans_resv.c > > > > > @@ -196,6 +196,24 @@ xfs_calc_inode_chunk_res( > > > > > return res; > > > > > } > > > > > > > > > > +/* > > > > > + * Per-extent log reservation for the btree changes involved in freeing or > > > > > + * allocating a realtime extent. We have to be able to log as many rtbitmap > > > > > + * blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents, > > > > > + * as well as the realtime summary block. > > > > > + */ > > > > > +unsigned int > > > > > +xfs_rtalloc_log_count( > > > > > + struct xfs_mount *mp, > > > > > + unsigned int num_ops) > > > > > +{ > > > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > > > + unsigned int rtbmp_bytes; > > > > > + > > > > > + rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY; > > > > > + return (howmany(rtbmp_bytes, blksz) + 1) * num_ops; > > > > > +} > > > > > + > > > > > /* > > > > > * Various log reservation values. > > > > > * > > > > > @@ -218,13 +236,21 @@ xfs_calc_inode_chunk_res( > > > > > > > > > > /* > > > > > * In a write transaction we can allocate a maximum of 2 > > > > > - * extents. This gives: > > > > > + * extents. This gives (t1): > > > > > * the inode getting the new extents: inode size > > > > > * the inode's bmap btree: max depth * block size > > > > > * the agfs of the ags from which the extents are allocated: 2 * sector > > > > > * the superblock free block counter: sector size > > > > > * the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size > > > > > - * And the bmap_finish transaction can free bmap blocks in a join: > > > > > + * Or, if we're writing to a realtime file (t2): > > > > > + * the inode getting the new extents: inode size > > > > > + * the inode's bmap btree: max depth * block size > > > > > + * the agfs of the ags from which the extents are allocated: 2 * sector > > > > > + * the superblock free block counter: sector size > > > > > + * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes > > > > > + * the realtime summary: 1 block > > > > > + * the allocation btrees: 2 trees * (2 * max depth - 1) * block size > > > > > > > > Why do we include the allocation btrees in the rt reservations? I > > > > thought that we'd either allocate (or free) out of one pool or the > > > > other. Do we operate on both sets of structures in the same transaction? > > > > > > I read "allocation btrees: 2 exts * 2 trees..." for t1 to mean that we > > > need to be able to allocate one datadev extent (which could cause a full > > > bnobt/cntbt split) for the actual file data, and then the second extent is > > > to handle allocating a new bmbt block to the bmap btree. > > > > > > > Ah, metadata out of the traditional trees.. that makes sense. My general > > understanding is that we have two sets of free space and thus two > > associated free space tracking structures: the traditional perag btrees > > for the local device and some bitmap indexing scheme for the external > > realtime device. Based on that, it looks like a file data allocation > > falls down into xfs_bmap_rtalloc() to allocate data blocks via the RT > > subsystem and the subsequent bmap update falls into the bmapbt code that > > uses xfs_alloc_vextent() directly to allocate blocks for the bmbt. > > > > With regard to the 2 extents, the first sentence in the comment above > > suggests to me that the two extents is a per-transaction operational > > limit. IOW, a write transaction supports two xfs_bmapi_write() calls, > > for example, as opposed to referring to the two lower level allocations > > outlined above. That seems consistent with the "2 * sector" AGF portion > > of the reservation as well, but I could easily be wrong about that. > > > > BTW I'm not following what you mean by a datadev extent causing a > > bnobt/cntbt split. Doesn't the data extent come from the RT free space, > > or are you just indirectly referring to the supporting bmbt block > > allocation causing a split..? > > "t1" is reflects writes to regular files on the datadev device, so > "allocate one datadev extent (which could cause a full bnobt/cntbt > split) for actual file data" applies to that case, not t2. > > "t2" is for writes to realtime files on the rt device. > > > > Based on that, I concluded that we still need to reserve space for that > > > "second" extent to handle allocating a new bmbt block (on the datadev). > > Perhaps my reply could have been clearer had I said: > > "Based on that, I concluded for the realtime case (t2) that we still..." > Ok. In any event, patch seems reasonable to me: Reviewed-by: Brian Foster <bfoster@redhat.com> > > > While pondering that, I wondered if even that's really true because what > > > happens if you suffer a full bmbt split, the free space is so fragmented > > > that each level of the bmbt split ends up allocating a new block from a > > > different part of the free space btrees and that in turn causes splits > > > in the free space btrees? > > > > > > I think the answer is "no we're fine" because even if each new bmbt > > > block comes from a different bnobt record, a full bmbt split will never > > > hollow out more than half of one bnobt block's worth of free space > > > records. > > > > > > > Yeah. I couldn't say for sure, but this strikes me as something we'd see > > reports of if it were possible/likely to occur in practice, particularly > > since this is the basis of how the allocation transaction reservations > > are calculated in general (not just for RT). > > <nod> > > --D > > > Brian > > > > > --D > > > > > > > Brian > > > > > > > > > + * And the bmap_finish transaction can free bmap blocks in a join (t3): > > > > > * the agfs of the ags containing the blocks: 2 * sector size > > > > > * the agfls of the ags containing the blocks: 2 * sector size > > > > > * the super block free block counter: sector size > > > > > @@ -234,40 +260,72 @@ STATIC uint > > > > > xfs_calc_write_reservation( > > > > > struct xfs_mount *mp) > > > > > { > > > > > - return XFS_DQUOT_LOGRES(mp) + > > > > > - max((xfs_calc_inode_res(mp, 1) + > > > > > + unsigned int t1, t2, t3; > > > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > > > + > > > > > + t1 = xfs_calc_inode_res(mp, 1) + > > > > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), blksz) + > > > > > + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > > > + > > > > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > > > > + t2 = xfs_calc_inode_res(mp, 1) + > > > > > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), > > > > > - XFS_FSB_TO_B(mp, 1)) + > > > > > + blksz) + > > > > > xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + > > > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > > > > - XFS_FSB_TO_B(mp, 1))), > > > > > - (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), > > > > > - XFS_FSB_TO_B(mp, 1)))); > > > > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 1), blksz) + > > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), blksz); > > > > > + } else { > > > > > + t2 = 0; > > > > > + } > > > > > + > > > > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > > > + > > > > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > > > > } > > > > > > > > > > /* > > > > > - * In truncating a file we free up to two extents at once. We can modify: > > > > > + * In truncating a file we free up to two extents at once. We can modify (t1): > > > > > * the inode being truncated: inode size > > > > > * the inode's bmap btree: (max depth + 1) * block size > > > > > - * And the bmap_finish transaction can free the blocks and bmap blocks: > > > > > + * And the bmap_finish transaction can free the blocks and bmap blocks (t2): > > > > > * the agf for each of the ags: 4 * sector size > > > > > * the agfl for each of the ags: 4 * sector size > > > > > * the super block to reflect the freed blocks: sector size > > > > > * worst case split in allocation btrees per extent assuming 4 extents: > > > > > * 4 exts * 2 trees * (2 * max depth - 1) * block size > > > > > + * Or, if it's a realtime file (t3): > > > > > + * the agf for each of the ags: 2 * sector size > > > > > + * the agfl for each of the ags: 2 * sector size > > > > > + * the super block to reflect the freed blocks: sector size > > > > > + * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes > > > > > + * the realtime summary: 2 exts * 1 block > > > > > + * worst case split in allocation btrees per extent assuming 2 extents: > > > > > + * 2 exts * 2 trees * (2 * max depth - 1) * block size > > > > > */ > > > > > STATIC uint > > > > > xfs_calc_itruncate_reservation( > > > > > struct xfs_mount *mp) > > > > > { > > > > > - return XFS_DQUOT_LOGRES(mp) + > > > > > - max((xfs_calc_inode_res(mp, 1) + > > > > > - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, > > > > > - XFS_FSB_TO_B(mp, 1))), > > > > > - (xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > > > > - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), > > > > > - XFS_FSB_TO_B(mp, 1)))); > > > > > + unsigned int t1, t2, t3; > > > > > + unsigned int blksz = XFS_FSB_TO_B(mp, 1); > > > > > + > > > > > + t1 = xfs_calc_inode_res(mp, 1) + > > > > > + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); > > > > > + > > > > > + t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + > > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), blksz); > > > > > + > > > > > + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > > > > > + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + > > > > > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + > > > > > + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); > > > > > + } else { > > > > > + t3 = 0; > > > > > + } > > > > > + > > > > > + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > > > > > } > > > > > > > > > > /* > > > > > > > > > > > > > > >
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c index c55cd9a3dec9..824073a839ac 100644 --- a/fs/xfs/libxfs/xfs_trans_resv.c +++ b/fs/xfs/libxfs/xfs_trans_resv.c @@ -196,6 +196,24 @@ xfs_calc_inode_chunk_res( return res; } +/* + * Per-extent log reservation for the btree changes involved in freeing or + * allocating a realtime extent. We have to be able to log as many rtbitmap + * blocks as needed to mark inuse MAXEXTLEN blocks' worth of realtime extents, + * as well as the realtime summary block. + */ +unsigned int +xfs_rtalloc_log_count( + struct xfs_mount *mp, + unsigned int num_ops) +{ + unsigned int blksz = XFS_FSB_TO_B(mp, 1); + unsigned int rtbmp_bytes; + + rtbmp_bytes = (MAXEXTLEN / mp->m_sb.sb_rextsize) / NBBY; + return (howmany(rtbmp_bytes, blksz) + 1) * num_ops; +} + /* * Various log reservation values. * @@ -218,13 +236,21 @@ xfs_calc_inode_chunk_res( /* * In a write transaction we can allocate a maximum of 2 - * extents. This gives: + * extents. This gives (t1): * the inode getting the new extents: inode size * the inode's bmap btree: max depth * block size * the agfs of the ags from which the extents are allocated: 2 * sector * the superblock free block counter: sector size * the allocation btrees: 2 exts * 2 trees * (2 * max depth - 1) * block size - * And the bmap_finish transaction can free bmap blocks in a join: + * Or, if we're writing to a realtime file (t2): + * the inode getting the new extents: inode size + * the inode's bmap btree: max depth * block size + * the agfs of the ags from which the extents are allocated: 2 * sector + * the superblock free block counter: sector size + * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes + * the realtime summary: 1 block + * the allocation btrees: 2 trees * (2 * max depth - 1) * block size + * And the bmap_finish transaction can free bmap blocks in a join (t3): * the agfs of the ags containing the blocks: 2 * sector size * the agfls of the ags containing the blocks: 2 * sector size * the super block free block counter: sector size @@ -234,40 +260,72 @@ STATIC uint xfs_calc_write_reservation( struct xfs_mount *mp) { - return XFS_DQUOT_LOGRES(mp) + - max((xfs_calc_inode_res(mp, 1) + + unsigned int t1, t2, t3; + unsigned int blksz = XFS_FSB_TO_B(mp, 1); + + t1 = xfs_calc_inode_res(mp, 1) + + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), blksz) + + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); + + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { + t2 = xfs_calc_inode_res(mp, 1) + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), - XFS_FSB_TO_B(mp, 1)) + + blksz) + xfs_calc_buf_res(3, mp->m_sb.sb_sectsize) + - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), - XFS_FSB_TO_B(mp, 1))), - (xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), - XFS_FSB_TO_B(mp, 1)))); + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 1), blksz) + + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 1), blksz); + } else { + t2 = 0; + } + + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); + + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); } /* - * In truncating a file we free up to two extents at once. We can modify: + * In truncating a file we free up to two extents at once. We can modify (t1): * the inode being truncated: inode size * the inode's bmap btree: (max depth + 1) * block size - * And the bmap_finish transaction can free the blocks and bmap blocks: + * And the bmap_finish transaction can free the blocks and bmap blocks (t2): * the agf for each of the ags: 4 * sector size * the agfl for each of the ags: 4 * sector size * the super block to reflect the freed blocks: sector size * worst case split in allocation btrees per extent assuming 4 extents: * 4 exts * 2 trees * (2 * max depth - 1) * block size + * Or, if it's a realtime file (t3): + * the agf for each of the ags: 2 * sector size + * the agfl for each of the ags: 2 * sector size + * the super block to reflect the freed blocks: sector size + * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes + * the realtime summary: 2 exts * 1 block + * worst case split in allocation btrees per extent assuming 2 extents: + * 2 exts * 2 trees * (2 * max depth - 1) * block size */ STATIC uint xfs_calc_itruncate_reservation( struct xfs_mount *mp) { - return XFS_DQUOT_LOGRES(mp) + - max((xfs_calc_inode_res(mp, 1) + - xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, - XFS_FSB_TO_B(mp, 1))), - (xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + - xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), - XFS_FSB_TO_B(mp, 1)))); + unsigned int t1, t2, t3; + unsigned int blksz = XFS_FSB_TO_B(mp, 1); + + t1 = xfs_calc_inode_res(mp, 1) + + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); + + t2 = xfs_calc_buf_res(9, mp->m_sb.sb_sectsize) + + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 4), blksz); + + if (xfs_sb_version_hasrealtime(&mp->m_sb)) { + t3 = xfs_calc_buf_res(5, mp->m_sb.sb_sectsize) + + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + + xfs_calc_buf_res(xfs_allocfree_log_count(mp, 2), blksz); + } else { + t3 = 0; + } + + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); } /*