From fe0be23e68200573de027de9b8cc2b27e7fce35e Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Wed, 12 Apr 2017 12:26:07 -0700 Subject: [PATCH] xfs: reserve enough blocks to handle btree splits when remapping In xfs_reflink_end_cow, we erroneously reserve only enough blocks to handle adding 1 extent. This is problematic if we fragment free space, have to do CoW, and then have to perform multiple bmap btree expansions. Furthermore, the BUI recovery routine doesn't reserve /any/ blocks to handle btree splits, so log recovery fails after our first error causes the filesystem to go down. Therefore, refactor the transaction block reservation macros until we have a macro that works for our deferred (re)mapping activities, and fix both problems by using that macro. With 1k blocks we can hit this fairly often in g/187 if the scratch fs is big enough. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_trans_space.h | 23 +++++++++++++++++------ fs/xfs/xfs_bmap_item.c | 5 ++++- fs/xfs/xfs_reflink.c | 18 ++++++++++++++++-- 3 files changed, 37 insertions(+), 9 deletions(-) diff --git a/fs/xfs/libxfs/xfs_trans_space.h b/fs/xfs/libxfs/xfs_trans_space.h index 7917f6e44286..d787c677d2a3 100644 --- a/fs/xfs/libxfs/xfs_trans_space.h +++ b/fs/xfs/libxfs/xfs_trans_space.h @@ -21,8 +21,20 @@ /* * Components of space reservations. */ + +/* Worst case number of rmaps that can be held in a block. */ #define XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) \ (((mp)->m_rmap_mxr[0]) - ((mp)->m_rmap_mnr[0])) + +/* Adding one rmap could split every level up to the top of the tree. */ +#define XFS_RMAPADD_SPACE_RES(mp) ((mp)->m_rmap_maxlevels) + +/* Blocks we might need to add "b" rmaps to a tree. */ +#define XFS_NRMAPADD_SPACE_RES(mp, b)\ + (((b + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) - 1) / \ + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp)) * \ + XFS_RMAPADD_SPACE_RES(mp)) + #define XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) \ (((mp)->m_alloc_mxr[0]) - ((mp)->m_alloc_mnr[0])) #define XFS_EXTENTADD_SPACE_RES(mp,w) (XFS_BM_MAXLEVELS(mp,w) - 1) @@ -30,13 +42,12 @@ (((b + XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) - 1) / \ XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp)) * \ XFS_EXTENTADD_SPACE_RES(mp,w)) + +/* Blocks we might need to add "b" mappings & rmappings to a file. */ #define XFS_SWAP_RMAP_SPACE_RES(mp,b,w)\ - (((b + XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) - 1) / \ - XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp)) * \ - XFS_EXTENTADD_SPACE_RES(mp,w) + \ - ((b + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) - 1) / \ - XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp)) * \ - (mp)->m_rmap_maxlevels) + (XFS_NEXTENTADD_SPACE_RES((mp), (b), (w)) + \ + XFS_NRMAPADD_SPACE_RES((mp), (b))) + #define XFS_DAENTER_1B(mp,w) \ ((w) == XFS_DATA_FORK ? (mp)->m_dir_geo->fsbcount : 1) #define XFS_DAENTER_DBS(mp,w) \ diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c index 2d7017373e20..d419d23fa214 100644 --- a/fs/xfs/xfs_bmap_item.c +++ b/fs/xfs/xfs_bmap_item.c @@ -34,6 +34,8 @@ #include "xfs_bmap.h" #include "xfs_icache.h" #include "xfs_trace.h" +#include "xfs_bmap_btree.h" +#include "xfs_trans_space.h" kmem_zone_t *xfs_bui_zone; @@ -447,7 +449,8 @@ xfs_bui_recover( return -EIO; } - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, + XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), 0, 0, &tp); if (error) return error; budp = xfs_trans_get_bud(tp, buip); diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index c0f3754caca2..ffe6fe7a7eb5 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -705,8 +705,22 @@ xfs_reflink_end_cow( offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count); - /* Start a rolling transaction to switch the mappings */ - resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK); + /* + * Start a rolling transaction to switch the mappings. We're + * unlikely ever to have to remap 16T worth of single-block + * extents, so just cap the worst case extent count to 2^32-1. + * Stick a warning in just in case, and avoid 64-bit division. + */ + BUILD_BUG_ON(MAX_RW_COUNT > UINT_MAX); + if (end_fsb - offset_fsb > UINT_MAX) { + error = -EFSCORRUPTED; + xfs_force_shutdown(ip->i_mount, SHUTDOWN_CORRUPT_INCORE); + ASSERT(0); + goto out; + } + resblks = XFS_NEXTENTADD_SPACE_RES(ip->i_mount, + (unsigned int)(end_fsb - offset_fsb), + XFS_DATA_FORK); error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write, resblks, 0, 0, &tp); if (error) -- 2.20.1