Commit b1de6fc7 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: fix log reservation overflows when allocating large rt extents 



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: default avatarOmar Sandoval <osandov@osandov.com>
Tested-by: default avatarOmar Sandoval <osandov@osandov.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
parent d0c22041

fs/xfs/libxfs/xfs_trans_resv.c

+77 −19
Original line number Diff line number Diff line
@@ -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);

}



/*

CRA Git | Maintained and supported by SUSTech CRA and CCSE