From bfe46d4eb9258cb3340eaf77a07ecc45875b3b17 Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Fri, 29 May 2015 08:53:00 +1000 Subject: [PATCH] xfs: support min/max agbno args in block allocator The block allocator supports various arguments to tweak block allocation behavior and set allocation requirements. The sparse inode chunk feature introduces a new requirement not supported by the current arguments. Sparse inode allocations must convert or merge into an inode record that describes a fixed length chunk (64 inodes x inodesize). Full inode chunk allocations by definition always result in valid inode records. Sparse chunk allocations are smaller and the associated records can refer to blocks not owned by the inode chunk. This model can result in invalid inode records in certain cases. For example, if a sparse allocation occurs near the start of an AG, the aligned inode record for that chunk might refer to agbno 0. If an allocation occurs towards the end of the AG and the AG size is not aligned, the inode record could refer to blocks beyond the end of the AG. While neither of these scenarios directly result in corruption, they both insert invalid inode records and at minimum cause repair to complain, are unlikely to merge into full chunks over time and set land mines for other areas of code. To guarantee sparse inode chunk allocation creates valid inode records, support the ability to specify an agbno range limit for XFS_ALLOCTYPE_NEAR_BNO block allocations. The min/max agbno's are specified in the allocation arguments and limit the block allocation algorithms to that range. The starting 'agbno' hint is clamped to the range if the specified agbno is out of range. If no sufficient extent is available within the range, the allocation fails. For backwards compatibility, the min/max fields can be initialized to 0 to disable range limiting (e.g., equivalent to min=0,max=agsize). Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_alloc.c | 42 ++++++++++++++++++++++++++++++++++----- fs/xfs/libxfs/xfs_alloc.h | 2 ++ 2 files changed, 39 insertions(+), 5 deletions(-) diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index 516162be1398..bc78ac08e72e 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -149,13 +149,27 @@ xfs_alloc_compute_aligned( { xfs_agblock_t bno; xfs_extlen_t len; + xfs_extlen_t diff; /* Trim busy sections out of found extent */ xfs_extent_busy_trim(args, foundbno, foundlen, &bno, &len); + /* + * If we have a largish extent that happens to start before min_agbno, + * see if we can shift it into range... + */ + if (bno < args->min_agbno && bno + len > args->min_agbno) { + diff = args->min_agbno - bno; + if (len > diff) { + bno += diff; + len -= diff; + } + } + if (args->alignment > 1 && len >= args->minlen) { xfs_agblock_t aligned_bno = roundup(bno, args->alignment); - xfs_extlen_t diff = aligned_bno - bno; + + diff = aligned_bno - bno; *resbno = aligned_bno; *reslen = diff >= len ? 0 : len - diff; @@ -795,9 +809,13 @@ xfs_alloc_find_best_extent( * The good extent is closer than this one. */ if (!dir) { + if (*sbnoa > args->max_agbno) + goto out_use_good; if (*sbnoa >= args->agbno + gdiff) goto out_use_good; } else { + if (*sbnoa < args->min_agbno) + goto out_use_good; if (*sbnoa <= args->agbno - gdiff) goto out_use_good; } @@ -884,6 +902,17 @@ xfs_alloc_ag_vextent_near( dofirst = prandom_u32() & 1; #endif + /* handle unitialized agbno range so caller doesn't have to */ + if (!args->min_agbno && !args->max_agbno) + args->max_agbno = args->mp->m_sb.sb_agblocks - 1; + ASSERT(args->min_agbno <= args->max_agbno); + + /* clamp agbno to the range if it's outside */ + if (args->agbno < args->min_agbno) + args->agbno = args->min_agbno; + if (args->agbno > args->max_agbno) + args->agbno = args->max_agbno; + restart: bno_cur_lt = NULL; bno_cur_gt = NULL; @@ -976,6 +1005,8 @@ xfs_alloc_ag_vextent_near( <bnoa, <lena); if (ltlena < args->minlen) continue; + if (ltbnoa < args->min_agbno || ltbnoa > args->max_agbno) + continue; args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen); xfs_alloc_fix_len(args); ASSERT(args->len >= args->minlen); @@ -1096,11 +1127,11 @@ xfs_alloc_ag_vextent_near( XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); xfs_alloc_compute_aligned(args, ltbno, ltlen, <bnoa, <lena); - if (ltlena >= args->minlen) + if (ltlena >= args->minlen && ltbnoa >= args->min_agbno) break; if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i))) goto error0; - if (!i) { + if (!i || ltbnoa < args->min_agbno) { xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR); bno_cur_lt = NULL; @@ -1112,11 +1143,11 @@ xfs_alloc_ag_vextent_near( XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0); xfs_alloc_compute_aligned(args, gtbno, gtlen, >bnoa, >lena); - if (gtlena >= args->minlen) + if (gtlena >= args->minlen && gtbnoa <= args->max_agbno) break; if ((error = xfs_btree_increment(bno_cur_gt, 0, &i))) goto error0; - if (!i) { + if (!i || gtbnoa > args->max_agbno) { xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_NOERROR); bno_cur_gt = NULL; @@ -1216,6 +1247,7 @@ xfs_alloc_ag_vextent_near( ASSERT(ltnew >= ltbno); ASSERT(ltnew + rlen <= ltbnoa + ltlena); ASSERT(ltnew + rlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length)); + ASSERT(ltnew >= args->min_agbno && ltnew <= args->max_agbno); args->agbno = ltnew; if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, ltlen, diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h index d1b4b6a5c894..29f27b272b7f 100644 --- a/fs/xfs/libxfs/xfs_alloc.h +++ b/fs/xfs/libxfs/xfs_alloc.h @@ -112,6 +112,8 @@ typedef struct xfs_alloc_arg { xfs_extlen_t total; /* total blocks needed in xaction */ xfs_extlen_t alignment; /* align answer to multiple of this */ xfs_extlen_t minalignslop; /* slop for minlen+alignment calcs */ + xfs_agblock_t min_agbno; /* set an agbno range for NEAR allocs */ + xfs_agblock_t max_agbno; /* ... */ xfs_extlen_t len; /* output: actual size of extent */ xfs_alloctype_t type; /* allocation type XFS_ALLOCTYPE_... */ xfs_alloctype_t otype; /* original allocation type */