diff options
Diffstat (limited to 'fs/xfs/xfs_alloc.c')
| -rw-r--r-- | fs/xfs/xfs_alloc.c | 3074 |
1 files changed, 3074 insertions, 0 deletions
diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c new file mode 100644 index 00000000..0f0df275 --- /dev/null +++ b/fs/xfs/xfs_alloc.c @@ -0,0 +1,3074 @@ +/* + * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc. + * All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_types.h" +#include "xfs_bit.h" +#include "xfs_log.h" +#include "xfs_inum.h" +#include "xfs_trans.h" +#include "xfs_sb.h" +#include "xfs_ag.h" +#include "xfs_mount.h" +#include "xfs_bmap_btree.h" +#include "xfs_alloc_btree.h" +#include "xfs_ialloc_btree.h" +#include "xfs_dinode.h" +#include "xfs_inode.h" +#include "xfs_btree.h" +#include "xfs_alloc.h" +#include "xfs_error.h" +#include "xfs_trace.h" + +struct workqueue_struct *xfs_alloc_wq; + +#define XFS_ABSDIFF(a,b) (((a) <= (b)) ? ((b) - (a)) : ((a) - (b))) + +#define XFSA_FIXUP_BNO_OK 1 +#define XFSA_FIXUP_CNT_OK 2 + +STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *); +STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *); +STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *); +STATIC int xfs_alloc_ag_vextent_small(xfs_alloc_arg_t *, + xfs_btree_cur_t *, xfs_agblock_t *, xfs_extlen_t *, int *); +STATIC void xfs_alloc_busy_trim(struct xfs_alloc_arg *, + xfs_agblock_t, xfs_extlen_t, xfs_agblock_t *, xfs_extlen_t *); + +/* + * Lookup the record equal to [bno, len] in the btree given by cur. + */ +STATIC int /* error */ +xfs_alloc_lookup_eq( + struct xfs_btree_cur *cur, /* btree cursor */ + xfs_agblock_t bno, /* starting block of extent */ + xfs_extlen_t len, /* length of extent */ + int *stat) /* success/failure */ +{ + cur->bc_rec.a.ar_startblock = bno; + cur->bc_rec.a.ar_blockcount = len; + return xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat); +} + +/* + * Lookup the first record greater than or equal to [bno, len] + * in the btree given by cur. + */ +int /* error */ +xfs_alloc_lookup_ge( + struct xfs_btree_cur *cur, /* btree cursor */ + xfs_agblock_t bno, /* starting block of extent */ + xfs_extlen_t len, /* length of extent */ + int *stat) /* success/failure */ +{ + cur->bc_rec.a.ar_startblock = bno; + cur->bc_rec.a.ar_blockcount = len; + return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat); +} + +/* + * Lookup the first record less than or equal to [bno, len] + * in the btree given by cur. + */ +int /* error */ +xfs_alloc_lookup_le( + struct xfs_btree_cur *cur, /* btree cursor */ + xfs_agblock_t bno, /* starting block of extent */ + xfs_extlen_t len, /* length of extent */ + int *stat) /* success/failure */ +{ + cur->bc_rec.a.ar_startblock = bno; + cur->bc_rec.a.ar_blockcount = len; + return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat); +} + +/* + * Update the record referred to by cur to the value given + * by [bno, len]. + * This either works (return 0) or gets an EFSCORRUPTED error. + */ +STATIC int /* error */ +xfs_alloc_update( + struct xfs_btree_cur *cur, /* btree cursor */ + xfs_agblock_t bno, /* starting block of extent */ + xfs_extlen_t len) /* length of extent */ +{ + union xfs_btree_rec rec; + + rec.alloc.ar_startblock = cpu_to_be32(bno); + rec.alloc.ar_blockcount = cpu_to_be32(len); + return xfs_btree_update(cur, &rec); +} + +/* + * Get the data from the pointed-to record. + */ +int /* error */ +xfs_alloc_get_rec( + struct xfs_btree_cur *cur, /* btree cursor */ + xfs_agblock_t *bno, /* output: starting block of extent */ + xfs_extlen_t *len, /* output: length of extent */ + int *stat) /* output: success/failure */ +{ + union xfs_btree_rec *rec; + int error; + + error = xfs_btree_get_rec(cur, &rec, stat); + if (!error && *stat == 1) { + *bno = be32_to_cpu(rec->alloc.ar_startblock); + *len = be32_to_cpu(rec->alloc.ar_blockcount); + } + return error; +} + +/* + * Compute aligned version of the found extent. + * Takes alignment and min length into account. + */ +STATIC void +xfs_alloc_compute_aligned( + xfs_alloc_arg_t *args, /* allocation argument structure */ + xfs_agblock_t foundbno, /* starting block in found extent */ + xfs_extlen_t foundlen, /* length in found extent */ + xfs_agblock_t *resbno, /* result block number */ + xfs_extlen_t *reslen) /* result length */ +{ + xfs_agblock_t bno; + xfs_extlen_t len; + + /* Trim busy sections out of found extent */ + xfs_alloc_busy_trim(args, foundbno, foundlen, &bno, &len); + + if (args->alignment > 1 && len >= args->minlen) { + xfs_agblock_t aligned_bno = roundup(bno, args->alignment); + xfs_extlen_t diff = aligned_bno - bno; + + *resbno = aligned_bno; + *reslen = diff >= len ? 0 : len - diff; + } else { + *resbno = bno; + *reslen = len; + } +} + +/* + * Compute best start block and diff for "near" allocations. + * freelen >= wantlen already checked by caller. + */ +STATIC xfs_extlen_t /* difference value (absolute) */ +xfs_alloc_compute_diff( + xfs_agblock_t wantbno, /* target starting block */ + xfs_extlen_t wantlen, /* target length */ + xfs_extlen_t alignment, /* target alignment */ + xfs_agblock_t freebno, /* freespace's starting block */ + xfs_extlen_t freelen, /* freespace's length */ + xfs_agblock_t *newbnop) /* result: best start block from free */ +{ + xfs_agblock_t freeend; /* end of freespace extent */ + xfs_agblock_t newbno1; /* return block number */ + xfs_agblock_t newbno2; /* other new block number */ + xfs_extlen_t newlen1=0; /* length with newbno1 */ + xfs_extlen_t newlen2=0; /* length with newbno2 */ + xfs_agblock_t wantend; /* end of target extent */ + + ASSERT(freelen >= wantlen); + freeend = freebno + freelen; + wantend = wantbno + wantlen; + if (freebno >= wantbno) { + if ((newbno1 = roundup(freebno, alignment)) >= freeend) + newbno1 = NULLAGBLOCK; + } else if (freeend >= wantend && alignment > 1) { + newbno1 = roundup(wantbno, alignment); + newbno2 = newbno1 - alignment; + if (newbno1 >= freeend) + newbno1 = NULLAGBLOCK; + else + newlen1 = XFS_EXTLEN_MIN(wantlen, freeend - newbno1); + if (newbno2 < freebno) + newbno2 = NULLAGBLOCK; + else + newlen2 = XFS_EXTLEN_MIN(wantlen, freeend - newbno2); + if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) { + if (newlen1 < newlen2 || + (newlen1 == newlen2 && + XFS_ABSDIFF(newbno1, wantbno) > + XFS_ABSDIFF(newbno2, wantbno))) + newbno1 = newbno2; + } else if (newbno2 != NULLAGBLOCK) + newbno1 = newbno2; + } else if (freeend >= wantend) { + newbno1 = wantbno; + } else if (alignment > 1) { + newbno1 = roundup(freeend - wantlen, alignment); + if (newbno1 > freeend - wantlen && + newbno1 - alignment >= freebno) + newbno1 -= alignment; + else if (newbno1 >= freeend) + newbno1 = NULLAGBLOCK; + } else + newbno1 = freeend - wantlen; + *newbnop = newbno1; + return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno); +} + +/* + * Fix up the length, based on mod and prod. + * len should be k * prod + mod for some k. + * If len is too small it is returned unchanged. + * If len hits maxlen it is left alone. + */ +STATIC void +xfs_alloc_fix_len( + xfs_alloc_arg_t *args) /* allocation argument structure */ +{ + xfs_extlen_t k; + xfs_extlen_t rlen; + + ASSERT(args->mod < args->prod); + rlen = args->len; + ASSERT(rlen >= args->minlen); + ASSERT(rlen <= args->maxlen); + if (args->prod <= 1 || rlen < args->mod || rlen == args->maxlen || + (args->mod == 0 && rlen < args->prod)) + return; + k = rlen % args->prod; + if (k == args->mod) + return; + if (k > args->mod) { + if ((int)(rlen = rlen - k - args->mod) < (int)args->minlen) + return; + } else { + if ((int)(rlen = rlen - args->prod - (args->mod - k)) < + (int)args->minlen) + return; + } + ASSERT(rlen >= args->minlen); + ASSERT(rlen <= args->maxlen); + args->len = rlen; +} + +/* + * Fix up length if there is too little space left in the a.g. + * Return 1 if ok, 0 if too little, should give up. + */ +STATIC int +xfs_alloc_fix_minleft( + xfs_alloc_arg_t *args) /* allocation argument structure */ +{ + xfs_agf_t *agf; /* a.g. freelist header */ + int diff; /* free space difference */ + + if (args->minleft == 0) + return 1; + agf = XFS_BUF_TO_AGF(args->agbp); + diff = be32_to_cpu(agf->agf_freeblks) + - args->len - args->minleft; + if (diff >= 0) + return 1; + args->len += diff; /* shrink the allocated space */ + if (args->len >= args->minlen) + return 1; + args->agbno = NULLAGBLOCK; + return 0; +} + +/* + * Update the two btrees, logically removing from freespace the extent + * starting at rbno, rlen blocks. The extent is contained within the + * actual (current) free extent fbno for flen blocks. + * Flags are passed in indicating whether the cursors are set to the + * relevant records. + */ +STATIC int /* error code */ +xfs_alloc_fixup_trees( + xfs_btree_cur_t *cnt_cur, /* cursor for by-size btree */ + xfs_btree_cur_t *bno_cur, /* cursor for by-block btree */ + xfs_agblock_t fbno, /* starting block of free extent */ + xfs_extlen_t flen, /* length of free extent */ + xfs_agblock_t rbno, /* starting block of returned extent */ + xfs_extlen_t rlen, /* length of returned extent */ + int flags) /* flags, XFSA_FIXUP_... */ +{ + int error; /* error code */ + int i; /* operation results */ + xfs_agblock_t nfbno1; /* first new free startblock */ + xfs_agblock_t nfbno2; /* second new free startblock */ + xfs_extlen_t nflen1=0; /* first new free length */ + xfs_extlen_t nflen2=0; /* second new free length */ + + /* + * Look up the record in the by-size tree if necessary. + */ + if (flags & XFSA_FIXUP_CNT_OK) { +#ifdef DEBUG + if ((error = xfs_alloc_get_rec(cnt_cur, &nfbno1, &nflen1, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN( + i == 1 && nfbno1 == fbno && nflen1 == flen); +#endif + } else { + if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 1); + } + /* + * Look up the record in the by-block tree if necessary. + */ + if (flags & XFSA_FIXUP_BNO_OK) { +#ifdef DEBUG + if ((error = xfs_alloc_get_rec(bno_cur, &nfbno1, &nflen1, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN( + i == 1 && nfbno1 == fbno && nflen1 == flen); +#endif + } else { + if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 1); + } + +#ifdef DEBUG + if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) { + struct xfs_btree_block *bnoblock; + struct xfs_btree_block *cntblock; + + bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_bufs[0]); + cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_bufs[0]); + + XFS_WANT_CORRUPTED_RETURN( + bnoblock->bb_numrecs == cntblock->bb_numrecs); + } +#endif + + /* + * Deal with all four cases: the allocated record is contained + * within the freespace record, so we can have new freespace + * at either (or both) end, or no freespace remaining. + */ + if (rbno == fbno && rlen == flen) + nfbno1 = nfbno2 = NULLAGBLOCK; + else if (rbno == fbno) { + nfbno1 = rbno + rlen; + nflen1 = flen - rlen; + nfbno2 = NULLAGBLOCK; + } else if (rbno + rlen == fbno + flen) { + nfbno1 = fbno; + nflen1 = flen - rlen; + nfbno2 = NULLAGBLOCK; + } else { + nfbno1 = fbno; + nflen1 = rbno - fbno; + nfbno2 = rbno + rlen; + nflen2 = (fbno + flen) - nfbno2; + } + /* + * Delete the entry from the by-size btree. + */ + if ((error = xfs_btree_delete(cnt_cur, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 1); + /* + * Add new by-size btree entry(s). + */ + if (nfbno1 != NULLAGBLOCK) { + if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 0); + if ((error = xfs_btree_insert(cnt_cur, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 1); + } + if (nfbno2 != NULLAGBLOCK) { + if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 0); + if ((error = xfs_btree_insert(cnt_cur, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 1); + } + /* + * Fix up the by-block btree entry(s). + */ + if (nfbno1 == NULLAGBLOCK) { + /* + * No remaining freespace, just delete the by-block tree entry. + */ + if ((error = xfs_btree_delete(bno_cur, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 1); + } else { + /* + * Update the by-block entry to start later|be shorter. + */ + if ((error = xfs_alloc_update(bno_cur, nfbno1, nflen1))) + return error; + } + if (nfbno2 != NULLAGBLOCK) { + /* + * 2 resulting free entries, need to add one. + */ + if ((error = xfs_alloc_lookup_eq(bno_cur, nfbno2, nflen2, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 0); + if ((error = xfs_btree_insert(bno_cur, &i))) + return error; + XFS_WANT_CORRUPTED_RETURN(i == 1); + } + return 0; +} + +/* + * Read in the allocation group free block array. + */ +STATIC int /* error */ +xfs_alloc_read_agfl( + xfs_mount_t *mp, /* mount point structure */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_agnumber_t agno, /* allocation group number */ + xfs_buf_t **bpp) /* buffer for the ag free block array */ +{ + xfs_buf_t *bp; /* return value */ + int error; + + ASSERT(agno != NULLAGNUMBER); + error = xfs_trans_read_buf( + mp, tp, mp->m_ddev_targp, + XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)), + XFS_FSS_TO_BB(mp, 1), 0, &bp); + if (error) + return error; + ASSERT(!xfs_buf_geterror(bp)); + xfs_buf_set_ref(bp, XFS_AGFL_REF); + *bpp = bp; + return 0; +} + +STATIC int +xfs_alloc_update_counters( + struct xfs_trans *tp, + struct xfs_perag *pag, + struct xfs_buf *agbp, + long len) +{ + struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp); + + pag->pagf_freeblks += len; + be32_add_cpu(&agf->agf_freeblks, len); + + xfs_trans_agblocks_delta(tp, len); + if (unlikely(be32_to_cpu(agf->agf_freeblks) > + be32_to_cpu(agf->agf_length))) + return EFSCORRUPTED; + + xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS); + return 0; +} + +/* + * Allocation group level functions. + */ + +/* + * Allocate a variable extent in the allocation group agno. + * Type and bno are used to determine where in the allocation group the + * extent will start. + * Extent's length (returned in *len) will be between minlen and maxlen, + * and of the form k * prod + mod unless there's nothing that large. + * Return the starting a.g. block, or NULLAGBLOCK if we can't do it. + */ +STATIC int /* error */ +xfs_alloc_ag_vextent( + xfs_alloc_arg_t *args) /* argument structure for allocation */ +{ + int error=0; + + ASSERT(args->minlen > 0); + ASSERT(args->maxlen > 0); + ASSERT(args->minlen <= args->maxlen); + ASSERT(args->mod < args->prod); + ASSERT(args->alignment > 0); + /* + * Branch to correct routine based on the type. + */ + args->wasfromfl = 0; + switch (args->type) { + case XFS_ALLOCTYPE_THIS_AG: + error = xfs_alloc_ag_vextent_size(args); + break; + case XFS_ALLOCTYPE_NEAR_BNO: + error = xfs_alloc_ag_vextent_near(args); + break; + case XFS_ALLOCTYPE_THIS_BNO: + error = xfs_alloc_ag_vextent_exact(args); + break; + default: + ASSERT(0); + /* NOTREACHED */ + } + + if (error || args->agbno == NULLAGBLOCK) + return error; + + ASSERT(args->len >= args->minlen); + ASSERT(args->len <= args->maxlen); + ASSERT(!args->wasfromfl || !args->isfl); + ASSERT(args->agbno % args->alignment == 0); + + if (!args->wasfromfl) { + error = xfs_alloc_update_counters(args->tp, args->pag, + args->agbp, + -((long)(args->len))); + if (error) + return error; + + ASSERT(!xfs_alloc_busy_search(args->mp, args->agno, + args->agbno, args->len)); + } + + if (!args->isfl) { + xfs_trans_mod_sb(args->tp, args->wasdel ? + XFS_TRANS_SB_RES_FDBLOCKS : + XFS_TRANS_SB_FDBLOCKS, + -((long)(args->len))); + } + + XFS_STATS_INC(xs_allocx); + XFS_STATS_ADD(xs_allocb, args->len); + return error; +} + +/* + * Allocate a variable extent at exactly agno/bno. + * Extent's length (returned in *len) will be between minlen and maxlen, + * and of the form k * prod + mod unless there's nothing that large. + * Return the starting a.g. block (bno), or NULLAGBLOCK if we can't do it. + */ +STATIC int /* error */ +xfs_alloc_ag_vextent_exact( + xfs_alloc_arg_t *args) /* allocation argument structure */ +{ + xfs_btree_cur_t *bno_cur;/* by block-number btree cursor */ + xfs_btree_cur_t *cnt_cur;/* by count btree cursor */ + int error; + xfs_agblock_t fbno; /* start block of found extent */ + xfs_extlen_t flen; /* length of found extent */ + xfs_agblock_t tbno; /* start block of trimmed extent */ + xfs_extlen_t tlen; /* length of trimmed extent */ + xfs_agblock_t tend; /* end block of trimmed extent */ + int i; /* success/failure of operation */ + + ASSERT(args->alignment == 1); + + /* + * Allocate/initialize a cursor for the by-number freespace btree. + */ + bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp, + args->agno, XFS_BTNUM_BNO); + + /* + * Lookup bno and minlen in the btree (minlen is irrelevant, really). + * Look for the closest free block <= bno, it must contain bno + * if any free block does. + */ + error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i); + if (error) + goto error0; + if (!i) + goto not_found; + + /* + * Grab the freespace record. + */ + error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i); + if (error) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + ASSERT(fbno <= args->agbno); + + /* + * Check for overlapping busy extents. + */ + xfs_alloc_busy_trim(args, fbno, flen, &tbno, &tlen); + + /* + * Give up if the start of the extent is busy, or the freespace isn't + * long enough for the minimum request. + */ + if (tbno > args->agbno) + goto not_found; + if (tlen < args->minlen) + goto not_found; + tend = tbno + tlen; + if (tend < args->agbno + args->minlen) + goto not_found; + + /* + * End of extent will be smaller of the freespace end and the + * maximal requested end. + * + * Fix the length according to mod and prod if given. + */ + args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen) + - args->agbno; + xfs_alloc_fix_len(args); + if (!xfs_alloc_fix_minleft(args)) + goto not_found; + + ASSERT(args->agbno + args->len <= tend); + + /* + * We are allocating agbno for args->len + * Allocate/initialize a cursor for the by-size btree. + */ + cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp, + args->agno, XFS_BTNUM_CNT); + ASSERT(args->agbno + args->len <= + be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length)); + error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno, + args->len, XFSA_FIXUP_BNO_OK); + if (error) { + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR); + goto error0; + } + + xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR); + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + + args->wasfromfl = 0; + trace_xfs_alloc_exact_done(args); + return 0; + +not_found: + /* Didn't find it, return null. */ + xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR); + args->agbno = NULLAGBLOCK; + trace_xfs_alloc_exact_notfound(args); + return 0; + +error0: + xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR); + trace_xfs_alloc_exact_error(args); + return error; +} + +/* + * Search the btree in a given direction via the search cursor and compare + * the records found against the good extent we've already found. + */ +STATIC int +xfs_alloc_find_best_extent( + struct xfs_alloc_arg *args, /* allocation argument structure */ + struct xfs_btree_cur **gcur, /* good cursor */ + struct xfs_btree_cur **scur, /* searching cursor */ + xfs_agblock_t gdiff, /* difference for search comparison */ + xfs_agblock_t *sbno, /* extent found by search */ + xfs_extlen_t *slen, /* extent length */ + xfs_agblock_t *sbnoa, /* aligned extent found by search */ + xfs_extlen_t *slena, /* aligned extent length */ + int dir) /* 0 = search right, 1 = search left */ +{ + xfs_agblock_t new; + xfs_agblock_t sdiff; + int error; + int i; + + /* The good extent is perfect, no need to search. */ + if (!gdiff) + goto out_use_good; + + /* + * Look until we find a better one, run out of space or run off the end. + */ + do { + error = xfs_alloc_get_rec(*scur, sbno, slen, &i); + if (error) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + xfs_alloc_compute_aligned(args, *sbno, *slen, sbnoa, slena); + + /* + * The good extent is closer than this one. + */ + if (!dir) { + if (*sbnoa >= args->agbno + gdiff) + goto out_use_good; + } else { + if (*sbnoa <= args->agbno - gdiff) + goto out_use_good; + } + + /* + * Same distance, compare length and pick the best. + */ + if (*slena >= args->minlen) { + args->len = XFS_EXTLEN_MIN(*slena, args->maxlen); + xfs_alloc_fix_len(args); + + sdiff = xfs_alloc_compute_diff(args->agbno, args->len, + args->alignment, *sbnoa, + *slena, &new); + + /* + * Choose closer size and invalidate other cursor. + */ + if (sdiff < gdiff) + goto out_use_search; + goto out_use_good; + } + + if (!dir) + error = xfs_btree_increment(*scur, 0, &i); + else + error = xfs_btree_decrement(*scur, 0, &i); + if (error) + goto error0; + } while (i); + +out_use_good: + xfs_btree_del_cursor(*scur, XFS_BTREE_NOERROR); + *scur = NULL; + return 0; + +out_use_search: + xfs_btree_del_cursor(*gcur, XFS_BTREE_NOERROR); + *gcur = NULL; + return 0; + +error0: + /* caller invalidates cursors */ + return error; +} + +/* + * Allocate a variable extent near bno in the allocation group agno. + * Extent's length (returned in len) will be between minlen and maxlen, + * and of the form k * prod + mod unless there's nothing that large. + * Return the starting a.g. block, or NULLAGBLOCK if we can't do it. + */ +STATIC int /* error */ +xfs_alloc_ag_vextent_near( + xfs_alloc_arg_t *args) /* allocation argument structure */ +{ + xfs_btree_cur_t *bno_cur_gt; /* cursor for bno btree, right side */ + xfs_btree_cur_t *bno_cur_lt; /* cursor for bno btree, left side */ + xfs_btree_cur_t *cnt_cur; /* cursor for count btree */ + xfs_agblock_t gtbno; /* start bno of right side entry */ + xfs_agblock_t gtbnoa; /* aligned ... */ + xfs_extlen_t gtdiff; /* difference to right side entry */ + xfs_extlen_t gtlen; /* length of right side entry */ + xfs_extlen_t gtlena; /* aligned ... */ + xfs_agblock_t gtnew; /* useful start bno of right side */ + int error; /* error code */ + int i; /* result code, temporary */ + int j; /* result code, temporary */ + xfs_agblock_t ltbno; /* start bno of left side entry */ + xfs_agblock_t ltbnoa; /* aligned ... */ + xfs_extlen_t ltdiff; /* difference to left side entry */ + xfs_extlen_t ltlen; /* length of left side entry */ + xfs_extlen_t ltlena; /* aligned ... */ + xfs_agblock_t ltnew; /* useful start bno of left side */ + xfs_extlen_t rlen; /* length of returned extent */ + int forced = 0; +#if defined(DEBUG) && defined(__KERNEL__) + /* + * Randomly don't execute the first algorithm. + */ + int dofirst; /* set to do first algorithm */ + + dofirst = random32() & 1; +#endif + +restart: + bno_cur_lt = NULL; + bno_cur_gt = NULL; + ltlen = 0; + gtlena = 0; + ltlena = 0; + + /* + * Get a cursor for the by-size btree. + */ + cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp, + args->agno, XFS_BTNUM_CNT); + + /* + * See if there are any free extents as big as maxlen. + */ + if ((error = xfs_alloc_lookup_ge(cnt_cur, 0, args->maxlen, &i))) + goto error0; + /* + * If none, then pick up the last entry in the tree unless the + * tree is empty. + */ + if (!i) { + if ((error = xfs_alloc_ag_vextent_small(args, cnt_cur, <bno, + <len, &i))) + goto error0; + if (i == 0 || ltlen == 0) { + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + trace_xfs_alloc_near_noentry(args); + return 0; + } + ASSERT(i == 1); + } + args->wasfromfl = 0; + + /* + * First algorithm. + * If the requested extent is large wrt the freespaces available + * in this a.g., then the cursor will be pointing to a btree entry + * near the right edge of the tree. If it's in the last btree leaf + * block, then we just examine all the entries in that block + * that are big enough, and pick the best one. + * This is written as a while loop so we can break out of it, + * but we never loop back to the top. + */ + while (xfs_btree_islastblock(cnt_cur, 0)) { + xfs_extlen_t bdiff; + int besti=0; + xfs_extlen_t blen=0; + xfs_agblock_t bnew=0; + +#if defined(DEBUG) && defined(__KERNEL__) + if (!dofirst) + break; +#endif + /* + * Start from the entry that lookup found, sequence through + * all larger free blocks. If we're actually pointing at a + * record smaller than maxlen, go to the start of this block, + * and skip all those smaller than minlen. + */ + if (ltlen || args->alignment > 1) { + cnt_cur->bc_ptrs[0] = 1; + do { + if ((error = xfs_alloc_get_rec(cnt_cur, <bno, + <len, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + if (ltlen >= args->minlen) + break; + if ((error = xfs_btree_increment(cnt_cur, 0, &i))) + goto error0; + } while (i); + ASSERT(ltlen >= args->minlen); + if (!i) + break; + } + i = cnt_cur->bc_ptrs[0]; + for (j = 1, blen = 0, bdiff = 0; + !error && j && (blen < args->maxlen || bdiff > 0); + error = xfs_btree_increment(cnt_cur, 0, &j)) { + /* + * For each entry, decide if it's better than + * the previous best entry. + */ + if ((error = xfs_alloc_get_rec(cnt_cur, <bno, <len, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + xfs_alloc_compute_aligned(args, ltbno, ltlen, + <bnoa, <lena); + if (ltlena < args->minlen) + continue; + args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen); + xfs_alloc_fix_len(args); + ASSERT(args->len >= args->minlen); + if (args->len < blen) + continue; + ltdiff = xfs_alloc_compute_diff(args->agbno, args->len, + args->alignment, ltbnoa, ltlena, <new); + if (ltnew != NULLAGBLOCK && + (args->len > blen || ltdiff < bdiff)) { + bdiff = ltdiff; + bnew = ltnew; + blen = args->len; + besti = cnt_cur->bc_ptrs[0]; + } + } + /* + * It didn't work. We COULD be in a case where + * there's a good record somewhere, so try again. + */ + if (blen == 0) + break; + /* + * Point at the best entry, and retrieve it again. + */ + cnt_cur->bc_ptrs[0] = besti; + if ((error = xfs_alloc_get_rec(cnt_cur, <bno, <len, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + ASSERT(ltbno + ltlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length)); + args->len = blen; + if (!xfs_alloc_fix_minleft(args)) { + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + trace_xfs_alloc_near_nominleft(args); + return 0; + } + blen = args->len; + /* + * We are allocating starting at bnew for blen blocks. + */ + args->agbno = bnew; + ASSERT(bnew >= ltbno); + ASSERT(bnew + blen <= ltbno + ltlen); + /* + * Set up a cursor for the by-bno tree. + */ + bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp, + args->agbp, args->agno, XFS_BTNUM_BNO); + /* + * Fix up the btree entries. + */ + if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, + ltlen, bnew, blen, XFSA_FIXUP_CNT_OK))) + goto error0; + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR); + + trace_xfs_alloc_near_first(args); + return 0; + } + /* + * Second algorithm. + * Search in the by-bno tree to the left and to the right + * simultaneously, until in each case we find a space big enough, + * or run into the edge of the tree. When we run into the edge, + * we deallocate that cursor. + * If both searches succeed, we compare the two spaces and pick + * the better one. + * With alignment, it's possible for both to fail; the upper + * level algorithm that picks allocation groups for allocations + * is not supposed to do this. + */ + /* + * Allocate and initialize the cursor for the leftward search. + */ + bno_cur_lt = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp, + args->agno, XFS_BTNUM_BNO); + /* + * Lookup <= bno to find the leftward search's starting point. + */ + if ((error = xfs_alloc_lookup_le(bno_cur_lt, args->agbno, args->maxlen, &i))) + goto error0; + if (!i) { + /* + * Didn't find anything; use this cursor for the rightward + * search. + */ + bno_cur_gt = bno_cur_lt; + bno_cur_lt = NULL; + } + /* + * Found something. Duplicate the cursor for the rightward search. + */ + else if ((error = xfs_btree_dup_cursor(bno_cur_lt, &bno_cur_gt))) + goto error0; + /* + * Increment the cursor, so we will point at the entry just right + * of the leftward entry if any, or to the leftmost entry. + */ + if ((error = xfs_btree_increment(bno_cur_gt, 0, &i))) + goto error0; + if (!i) { + /* + * It failed, there are no rightward entries. + */ + xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_NOERROR); + bno_cur_gt = NULL; + } + /* + * Loop going left with the leftward cursor, right with the + * rightward cursor, until either both directions give up or + * we find an entry at least as big as minlen. + */ + do { + if (bno_cur_lt) { + if ((error = xfs_alloc_get_rec(bno_cur_lt, <bno, <len, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + xfs_alloc_compute_aligned(args, ltbno, ltlen, + <bnoa, <lena); + if (ltlena >= args->minlen) + break; + if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i))) + goto error0; + if (!i) { + xfs_btree_del_cursor(bno_cur_lt, + XFS_BTREE_NOERROR); + bno_cur_lt = NULL; + } + } + if (bno_cur_gt) { + if ((error = xfs_alloc_get_rec(bno_cur_gt, >bno, >len, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + xfs_alloc_compute_aligned(args, gtbno, gtlen, + >bnoa, >lena); + if (gtlena >= args->minlen) + break; + if ((error = xfs_btree_increment(bno_cur_gt, 0, &i))) + goto error0; + if (!i) { + xfs_btree_del_cursor(bno_cur_gt, + XFS_BTREE_NOERROR); + bno_cur_gt = NULL; + } + } + } while (bno_cur_lt || bno_cur_gt); + + /* + * Got both cursors still active, need to find better entry. + */ + if (bno_cur_lt && bno_cur_gt) { + if (ltlena >= args->minlen) { + /* + * Left side is good, look for a right side entry. + */ + args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen); + xfs_alloc_fix_len(args); + ltdiff = xfs_alloc_compute_diff(args->agbno, args->len, + args->alignment, ltbnoa, ltlena, <new); + + error = xfs_alloc_find_best_extent(args, + &bno_cur_lt, &bno_cur_gt, + ltdiff, >bno, >len, + >bnoa, >lena, + 0 /* search right */); + } else { + ASSERT(gtlena >= args->minlen); + + /* + * Right side is good, look for a left side entry. + */ + args->len = XFS_EXTLEN_MIN(gtlena, args->maxlen); + xfs_alloc_fix_len(args); + gtdiff = xfs_alloc_compute_diff(args->agbno, args->len, + args->alignment, gtbnoa, gtlena, >new); + + error = xfs_alloc_find_best_extent(args, + &bno_cur_gt, &bno_cur_lt, + gtdiff, <bno, <len, + <bnoa, <lena, + 1 /* search left */); + } + + if (error) + goto error0; + } + + /* + * If we couldn't get anything, give up. + */ + if (bno_cur_lt == NULL && bno_cur_gt == NULL) { + if (!forced++) { + trace_xfs_alloc_near_busy(args); + xfs_log_force(args->mp, XFS_LOG_SYNC); + goto restart; + } + + trace_xfs_alloc_size_neither(args); + args->agbno = NULLAGBLOCK; + return 0; + } + + /* + * At this point we have selected a freespace entry, either to the + * left or to the right. If it's on the right, copy all the + * useful variables to the "left" set so we only have one + * copy of this code. + */ + if (bno_cur_gt) { + bno_cur_lt = bno_cur_gt; + bno_cur_gt = NULL; + ltbno = gtbno; + ltbnoa = gtbnoa; + ltlen = gtlen; + ltlena = gtlena; + j = 1; + } else + j = 0; + + /* + * Fix up the length and compute the useful address. + */ + args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen); + xfs_alloc_fix_len(args); + if (!xfs_alloc_fix_minleft(args)) { + trace_xfs_alloc_near_nominleft(args); + xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR); + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + return 0; + } + rlen = args->len; + (void)xfs_alloc_compute_diff(args->agbno, rlen, args->alignment, + ltbnoa, ltlena, <new); + ASSERT(ltnew >= ltbno); + ASSERT(ltnew + rlen <= ltbnoa + ltlena); + ASSERT(ltnew + rlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length)); + args->agbno = ltnew; + + if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, ltlen, + ltnew, rlen, XFSA_FIXUP_BNO_OK))) + goto error0; + + if (j) + trace_xfs_alloc_near_greater(args); + else + trace_xfs_alloc_near_lesser(args); + + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR); + return 0; + + error0: + trace_xfs_alloc_near_error(args); + if (cnt_cur != NULL) + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR); + if (bno_cur_lt != NULL) + xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_ERROR); + if (bno_cur_gt != NULL) + xfs_btree_del_cursor(bno_cur_gt, XFS_BTREE_ERROR); + return error; +} + +/* + * Allocate a variable extent anywhere in the allocation group agno. + * Extent's length (returned in len) will be between minlen and maxlen, + * and of the form k * prod + mod unless there's nothing that large. + * Return the starting a.g. block, or NULLAGBLOCK if we can't do it. + */ +STATIC int /* error */ +xfs_alloc_ag_vextent_size( + xfs_alloc_arg_t *args) /* allocation argument structure */ +{ + xfs_btree_cur_t *bno_cur; /* cursor for bno btree */ + xfs_btree_cur_t *cnt_cur; /* cursor for cnt btree */ + int error; /* error result */ + xfs_agblock_t fbno; /* start of found freespace */ + xfs_extlen_t flen; /* length of found freespace */ + int i; /* temp status variable */ + xfs_agblock_t rbno; /* returned block number */ + xfs_extlen_t rlen; /* length of returned extent */ + int forced = 0; + +restart: + /* + * Allocate and initialize a cursor for the by-size btree. + */ + cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp, + args->agno, XFS_BTNUM_CNT); + bno_cur = NULL; + + /* + * Look for an entry >= maxlen+alignment-1 blocks. + */ + if ((error = xfs_alloc_lookup_ge(cnt_cur, 0, + args->maxlen + args->alignment - 1, &i))) + goto error0; + + /* + * If none or we have busy extents that we cannot allocate from, then + * we have to settle for a smaller extent. In the case that there are + * no large extents, this will return the last entry in the tree unless + * the tree is empty. In the case that there are only busy large + * extents, this will return the largest small extent unless there + * are no smaller extents available. + */ + if (!i || forced > 1) { + error = xfs_alloc_ag_vextent_small(args, cnt_cur, + &fbno, &flen, &i); + if (error) + goto error0; + if (i == 0 || flen == 0) { + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + trace_xfs_alloc_size_noentry(args); + return 0; + } + ASSERT(i == 1); + xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen); + } else { + /* + * Search for a non-busy extent that is large enough. + * If we are at low space, don't check, or if we fall of + * the end of the btree, turn off the busy check and + * restart. + */ + for (;;) { + error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i); + if (error) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + + xfs_alloc_compute_aligned(args, fbno, flen, + &rbno, &rlen); + + if (rlen >= args->maxlen) + break; + + error = xfs_btree_increment(cnt_cur, 0, &i); + if (error) + goto error0; + if (i == 0) { + /* + * Our only valid extents must have been busy. + * Make it unbusy by forcing the log out and + * retrying. If we've been here before, forcing + * the log isn't making the extents available, + * which means they have probably been freed in + * this transaction. In that case, we have to + * give up on them and we'll attempt a minlen + * allocation the next time around. + */ + xfs_btree_del_cursor(cnt_cur, + XFS_BTREE_NOERROR); + trace_xfs_alloc_size_busy(args); + if (!forced++) + xfs_log_force(args->mp, XFS_LOG_SYNC); + goto restart; + } + } + } + + /* + * In the first case above, we got the last entry in the + * by-size btree. Now we check to see if the space hits maxlen + * once aligned; if not, we search left for something better. + * This can't happen in the second case above. + */ + rlen = XFS_EXTLEN_MIN(args->maxlen, rlen); + XFS_WANT_CORRUPTED_GOTO(rlen == 0 || + (rlen <= flen && rbno + rlen <= fbno + flen), error0); + if (rlen < args->maxlen) { + xfs_agblock_t bestfbno; + xfs_extlen_t bestflen; + xfs_agblock_t bestrbno; + xfs_extlen_t bestrlen; + + bestrlen = rlen; + bestrbno = rbno; + bestflen = flen; + bestfbno = fbno; + for (;;) { + if ((error = xfs_btree_decrement(cnt_cur, 0, &i))) + goto error0; + if (i == 0) + break; + if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, + &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + if (flen < bestrlen) + break; + xfs_alloc_compute_aligned(args, fbno, flen, + &rbno, &rlen); + rlen = XFS_EXTLEN_MIN(args->maxlen, rlen); + XFS_WANT_CORRUPTED_GOTO(rlen == 0 || + (rlen <= flen && rbno + rlen <= fbno + flen), + error0); + if (rlen > bestrlen) { + bestrlen = rlen; + bestrbno = rbno; + bestflen = flen; + bestfbno = fbno; + if (rlen == args->maxlen) + break; + } + } + if ((error = xfs_alloc_lookup_eq(cnt_cur, bestfbno, bestflen, + &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + rlen = bestrlen; + rbno = bestrbno; + flen = bestflen; + fbno = bestfbno; + } + args->wasfromfl = 0; + /* + * Fix up the length. + */ + args->len = rlen; + if (rlen < args->minlen) { + if (!forced++) { + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + trace_xfs_alloc_size_busy(args); + xfs_log_force(args->mp, XFS_LOG_SYNC); + goto restart; + } + goto out_nominleft; + } + xfs_alloc_fix_len(args); + + if (!xfs_alloc_fix_minleft(args)) + goto out_nominleft; + rlen = args->len; + XFS_WANT_CORRUPTED_GOTO(rlen <= flen, error0); + /* + * Allocate and initialize a cursor for the by-block tree. + */ + bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp, + args->agno, XFS_BTNUM_BNO); + if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, + rbno, rlen, XFSA_FIXUP_CNT_OK))) + goto error0; + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR); + cnt_cur = bno_cur = NULL; + args->len = rlen; + args->agbno = rbno; + XFS_WANT_CORRUPTED_GOTO( + args->agbno + args->len <= + be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length), + error0); + trace_xfs_alloc_size_done(args); + return 0; + +error0: + trace_xfs_alloc_size_error(args); + if (cnt_cur) + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR); + if (bno_cur) + xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR); + return error; + +out_nominleft: + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + trace_xfs_alloc_size_nominleft(args); + args->agbno = NULLAGBLOCK; + return 0; +} + +/* + * Deal with the case where only small freespaces remain. + * Either return the contents of the last freespace record, + * or allocate space from the freelist if there is nothing in the tree. + */ +STATIC int /* error */ +xfs_alloc_ag_vextent_small( + xfs_alloc_arg_t *args, /* allocation argument structure */ + xfs_btree_cur_t *ccur, /* by-size cursor */ + xfs_agblock_t *fbnop, /* result block number */ + xfs_extlen_t *flenp, /* result length */ + int *stat) /* status: 0-freelist, 1-normal/none */ +{ + int error; + xfs_agblock_t fbno; + xfs_extlen_t flen; + int i; + + if ((error = xfs_btree_decrement(ccur, 0, &i))) + goto error0; + if (i) { + if ((error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + } + /* + * Nothing in the btree, try the freelist. Make sure + * to respect minleft even when pulling from the + * freelist. + */ + else if (args->minlen == 1 && args->alignment == 1 && !args->isfl && + (be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_flcount) + > args->minleft)) { + error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0); + if (error) + goto error0; + if (fbno != NULLAGBLOCK) { + xfs_alloc_busy_reuse(args->mp, args->agno, fbno, 1, + args->userdata); + + if (args->userdata) { + xfs_buf_t *bp; + + bp = xfs_btree_get_bufs(args->mp, args->tp, + args->agno, fbno, 0); + xfs_trans_binval(args->tp, bp); + } + args->len = 1; + args->agbno = fbno; + XFS_WANT_CORRUPTED_GOTO( + args->agbno + args->len <= + be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length), + error0); + args->wasfromfl = 1; + trace_xfs_alloc_small_freelist(args); + *stat = 0; + return 0; + } + /* + * Nothing in the freelist. + */ + else + flen = 0; + } + /* + * Can't allocate from the freelist for some reason. + */ + else { + fbno = NULLAGBLOCK; + flen = 0; + } + /* + * Can't do the allocation, give up. + */ + if (flen < args->minlen) { + args->agbno = NULLAGBLOCK; + trace_xfs_alloc_small_notenough(args); + flen = 0; + } + *fbnop = fbno; + *flenp = flen; + *stat = 1; + trace_xfs_alloc_small_done(args); + return 0; + +error0: + trace_xfs_alloc_small_error(args); + return error; +} + +/* + * Free the extent starting at agno/bno for length. + */ +STATIC int /* error */ +xfs_free_ag_extent( + xfs_trans_t *tp, /* transaction pointer */ + xfs_buf_t *agbp, /* buffer for a.g. freelist header */ + xfs_agnumber_t agno, /* allocation group number */ + xfs_agblock_t bno, /* starting block number */ + xfs_extlen_t len, /* length of extent */ + int isfl) /* set if is freelist blocks - no sb acctg */ +{ + xfs_btree_cur_t *bno_cur; /* cursor for by-block btree */ + xfs_btree_cur_t *cnt_cur; /* cursor for by-size btree */ + int error; /* error return value */ + xfs_agblock_t gtbno; /* start of right neighbor block */ + xfs_extlen_t gtlen; /* length of right neighbor block */ + int haveleft; /* have a left neighbor block */ + int haveright; /* have a right neighbor block */ + int i; /* temp, result code */ + xfs_agblock_t ltbno; /* start of left neighbor block */ + xfs_extlen_t ltlen; /* length of left neighbor block */ + xfs_mount_t *mp; /* mount point struct for filesystem */ + xfs_agblock_t nbno; /* new starting block of freespace */ + xfs_extlen_t nlen; /* new length of freespace */ + xfs_perag_t *pag; /* per allocation group data */ + + mp = tp->t_mountp; + /* + * Allocate and initialize a cursor for the by-block btree. + */ + bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO); + cnt_cur = NULL; + /* + * Look for a neighboring block on the left (lower block numbers) + * that is contiguous with this space. + */ + if ((error = xfs_alloc_lookup_le(bno_cur, bno, len, &haveleft))) + goto error0; + if (haveleft) { + /* + * There is a block to our left. + */ + if ((error = xfs_alloc_get_rec(bno_cur, <bno, <len, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + /* + * It's not contiguous, though. + */ + if (ltbno + ltlen < bno) + haveleft = 0; + else { + /* + * If this failure happens the request to free this + * space was invalid, it's (partly) already free. + * Very bad. + */ + XFS_WANT_CORRUPTED_GOTO(ltbno + ltlen <= bno, error0); + } + } + /* + * Look for a neighboring block on the right (higher block numbers) + * that is contiguous with this space. + */ + if ((error = xfs_btree_increment(bno_cur, 0, &haveright))) + goto error0; + if (haveright) { + /* + * There is a block to our right. + */ + if ((error = xfs_alloc_get_rec(bno_cur, >bno, >len, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + /* + * It's not contiguous, though. + */ + if (bno + len < gtbno) + haveright = 0; + else { + /* + * If this failure happens the request to free this + * space was invalid, it's (partly) already free. + * Very bad. + */ + XFS_WANT_CORRUPTED_GOTO(gtbno >= bno + len, error0); + } + } + /* + * Now allocate and initialize a cursor for the by-size tree. + */ + cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT); + /* + * Have both left and right contiguous neighbors. + * Merge all three into a single free block. + */ + if (haveleft && haveright) { + /* + * Delete the old by-size entry on the left. + */ + if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + if ((error = xfs_btree_delete(cnt_cur, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + /* + * Delete the old by-size entry on the right. + */ + if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + if ((error = xfs_btree_delete(cnt_cur, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + /* + * Delete the old by-block entry for the right block. + */ + if ((error = xfs_btree_delete(bno_cur, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + /* + * Move the by-block cursor back to the left neighbor. + */ + if ((error = xfs_btree_decrement(bno_cur, 0, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); +#ifdef DEBUG + /* + * Check that this is the right record: delete didn't + * mangle the cursor. + */ + { + xfs_agblock_t xxbno; + xfs_extlen_t xxlen; + + if ((error = xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen, + &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO( + i == 1 && xxbno == ltbno && xxlen == ltlen, + error0); + } +#endif + /* + * Update remaining by-block entry to the new, joined block. + */ + nbno = ltbno; + nlen = len + ltlen + gtlen; + if ((error = xfs_alloc_update(bno_cur, nbno, nlen))) + goto error0; + } + /* + * Have only a left contiguous neighbor. + * Merge it together with the new freespace. + */ + else if (haveleft) { + /* + * Delete the old by-size entry on the left. + */ + if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + if ((error = xfs_btree_delete(cnt_cur, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + /* + * Back up the by-block cursor to the left neighbor, and + * update its length. + */ + if ((error = xfs_btree_decrement(bno_cur, 0, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + nbno = ltbno; + nlen = len + ltlen; + if ((error = xfs_alloc_update(bno_cur, nbno, nlen))) + goto error0; + } + /* + * Have only a right contiguous neighbor. + * Merge it together with the new freespace. + */ + else if (haveright) { + /* + * Delete the old by-size entry on the right. + */ + if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + if ((error = xfs_btree_delete(cnt_cur, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + /* + * Update the starting block and length of the right + * neighbor in the by-block tree. + */ + nbno = bno; + nlen = len + gtlen; + if ((error = xfs_alloc_update(bno_cur, nbno, nlen))) + goto error0; + } + /* + * No contiguous neighbors. + * Insert the new freespace into the by-block tree. + */ + else { + nbno = bno; + nlen = len; + if ((error = xfs_btree_insert(bno_cur, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + } + xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR); + bno_cur = NULL; + /* + * In all cases we need to insert the new freespace in the by-size tree. + */ + if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 0, error0); + if ((error = xfs_btree_insert(cnt_cur, &i))) + goto error0; + XFS_WANT_CORRUPTED_GOTO(i == 1, error0); + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR); + cnt_cur = NULL; + + /* + * Update the freespace totals in the ag and superblock. + */ + pag = xfs_perag_get(mp, agno); + error = xfs_alloc_update_counters(tp, pag, agbp, len); + xfs_perag_put(pag); + if (error) + goto error0; + + if (!isfl) + xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (long)len); + XFS_STATS_INC(xs_freex); + XFS_STATS_ADD(xs_freeb, len); + + trace_xfs_free_extent(mp, agno, bno, len, isfl, haveleft, haveright); + + return 0; + + error0: + trace_xfs_free_extent(mp, agno, bno, len, isfl, -1, -1); + if (bno_cur) + xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR); + if (cnt_cur) + xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR); + return error; +} + +/* + * Visible (exported) allocation/free functions. + * Some of these are used just by xfs_alloc_btree.c and this file. + */ + +/* + * Compute and fill in value of m_ag_maxlevels. + */ +void +xfs_alloc_compute_maxlevels( + xfs_mount_t *mp) /* file system mount structure */ +{ + int level; + uint maxblocks; + uint maxleafents; + int minleafrecs; + int minnoderecs; + + maxleafents = (mp->m_sb.sb_agblocks + 1) / 2; + minleafrecs = mp->m_alloc_mnr[0]; + minnoderecs = mp->m_alloc_mnr[1]; + maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs; + for (level = 1; maxblocks > 1; level++) + maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs; + mp->m_ag_maxlevels = level; +} + +/* + * Find the length of the longest extent in an AG. + */ +xfs_extlen_t +xfs_alloc_longest_free_extent( + struct xfs_mount *mp, + struct xfs_perag *pag) +{ + xfs_extlen_t need, delta = 0; + + need = XFS_MIN_FREELIST_PAG(pag, mp); + if (need > pag->pagf_flcount) + delta = need - pag->pagf_flcount; + + if (pag->pagf_longest > delta) + return pag->pagf_longest - delta; + return pag->pagf_flcount > 0 || pag->pagf_longest > 0; +} + +/* + * Decide whether to use this allocation group for this allocation. + * If so, fix up the btree freelist's size. + */ +STATIC int /* error */ +xfs_alloc_fix_freelist( + xfs_alloc_arg_t *args, /* allocation argument structure */ + int flags) /* XFS_ALLOC_FLAG_... */ +{ + xfs_buf_t *agbp; /* agf buffer pointer */ + xfs_agf_t *agf; /* a.g. freespace structure pointer */ + xfs_buf_t *agflbp;/* agfl buffer pointer */ + xfs_agblock_t bno; /* freelist block */ + xfs_extlen_t delta; /* new blocks needed in freelist */ + int error; /* error result code */ + xfs_extlen_t longest;/* longest extent in allocation group */ + xfs_mount_t *mp; /* file system mount point structure */ + xfs_extlen_t need; /* total blocks needed in freelist */ + xfs_perag_t *pag; /* per-ag information structure */ + xfs_alloc_arg_t targs; /* local allocation arguments */ + xfs_trans_t *tp; /* transaction pointer */ + + mp = args->mp; + + pag = args->pag; + tp = args->tp; + if (!pag->pagf_init) { + if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags, + &agbp))) + return error; + if (!pag->pagf_init) { + ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK); + ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING)); + args->agbp = NULL; + return 0; + } + } else + agbp = NULL; + + /* + * If this is a metadata preferred pag and we are user data + * then try somewhere else if we are not being asked to + * try harder at this point + */ + if (pag->pagf_metadata && args->userdata && + (flags & XFS_ALLOC_FLAG_TRYLOCK)) { + ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING)); + args->agbp = NULL; + return 0; + } + + if (!(flags & XFS_ALLOC_FLAG_FREEING)) { + /* + * If it looks like there isn't a long enough extent, or enough + * total blocks, reject it. + */ + need = XFS_MIN_FREELIST_PAG(pag, mp); + longest = xfs_alloc_longest_free_extent(mp, pag); + if ((args->minlen + args->alignment + args->minalignslop - 1) > + longest || + ((int)(pag->pagf_freeblks + pag->pagf_flcount - + need - args->total) < (int)args->minleft)) { + if (agbp) + xfs_trans_brelse(tp, agbp); + args->agbp = NULL; + return 0; + } + } + + /* + * Get the a.g. freespace buffer. + * Can fail if we're not blocking on locks, and it's held. + */ + if (agbp == NULL) { + if ((error = xfs_alloc_read_agf(mp, tp, args->agno, flags, + &agbp))) + return error; + if (agbp == NULL) { + ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK); + ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING)); + args->agbp = NULL; + return 0; + } + } + /* + * Figure out how many blocks we should have in the freelist. + */ + agf = XFS_BUF_TO_AGF(agbp); + need = XFS_MIN_FREELIST(agf, mp); + /* + * If there isn't enough total or single-extent, reject it. + */ + if (!(flags & XFS_ALLOC_FLAG_FREEING)) { + delta = need > be32_to_cpu(agf->agf_flcount) ? + (need - be32_to_cpu(agf->agf_flcount)) : 0; + longest = be32_to_cpu(agf->agf_longest); + longest = (longest > delta) ? (longest - delta) : + (be32_to_cpu(agf->agf_flcount) > 0 || longest > 0); + if ((args->minlen + args->alignment + args->minalignslop - 1) > + longest || + ((int)(be32_to_cpu(agf->agf_freeblks) + + be32_to_cpu(agf->agf_flcount) - need - args->total) < + (int)args->minleft)) { + xfs_trans_brelse(tp, agbp); + args->agbp = NULL; + return 0; + } + } + /* + * Make the freelist shorter if it's too long. + */ + while (be32_to_cpu(agf->agf_flcount) > need) { + xfs_buf_t *bp; + + error = xfs_alloc_get_freelist(tp, agbp, &bno, 0); + if (error) + return error; + if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1))) + return error; + bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0); + xfs_trans_binval(tp, bp); + } + /* + * Initialize the args structure. + */ + targs.tp = tp; + targs.mp = mp; + targs.agbp = agbp; + targs.agno = args->agno; + targs.mod = targs.minleft = targs.wasdel = targs.userdata = + targs.minalignslop = 0; + targs.alignment = targs.minlen = targs.prod = targs.isfl = 1; + targs.type = XFS_ALLOCTYPE_THIS_AG; + targs.pag = pag; + if ((error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp))) + return error; + /* + * Make the freelist longer if it's too short. + */ + while (be32_to_cpu(agf->agf_flcount) < need) { + targs.agbno = 0; + targs.maxlen = need - be32_to_cpu(agf->agf_flcount); + /* + * Allocate as many blocks as possible at once. + */ + if ((error = xfs_alloc_ag_vextent(&targs))) { + xfs_trans_brelse(tp, agflbp); + return error; + } + /* + * Stop if we run out. Won't happen if callers are obeying + * the restrictions correctly. Can happen for free calls + * on a completely full ag. + */ + if (targs.agbno == NULLAGBLOCK) { + if (flags & XFS_ALLOC_FLAG_FREEING) + break; + xfs_trans_brelse(tp, agflbp); + args->agbp = NULL; + return 0; + } + /* + * Put each allocated block on the list. + */ + for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) { + error = xfs_alloc_put_freelist(tp, agbp, + agflbp, bno, 0); + if (error) + return error; + } + } + xfs_trans_brelse(tp, agflbp); + args->agbp = agbp; + return 0; +} + +/* + * Get a block from the freelist. + * Returns with the buffer for the block gotten. + */ +int /* error */ +xfs_alloc_get_freelist( + xfs_trans_t *tp, /* transaction pointer */ + xfs_buf_t *agbp, /* buffer containing the agf structure */ + xfs_agblock_t *bnop, /* block address retrieved from freelist */ + int btreeblk) /* destination is a AGF btree */ +{ + xfs_agf_t *agf; /* a.g. freespace structure */ + xfs_agfl_t *agfl; /* a.g. freelist structure */ + xfs_buf_t *agflbp;/* buffer for a.g. freelist structure */ + xfs_agblock_t bno; /* block number returned */ + int error; + int logflags; + xfs_mount_t *mp; /* mount structure */ + xfs_perag_t *pag; /* per allocation group data */ + + agf = XFS_BUF_TO_AGF(agbp); + /* + * Freelist is empty, give up. + */ + if (!agf->agf_flcount) { + *bnop = NULLAGBLOCK; + return 0; + } + /* + * Read the array of free blocks. + */ + mp = tp->t_mountp; + if ((error = xfs_alloc_read_agfl(mp, tp, + be32_to_cpu(agf->agf_seqno), &agflbp))) + return error; + agfl = XFS_BUF_TO_AGFL(agflbp); + /* + * Get the block number and update the data structures. + */ + bno = be32_to_cpu(agfl->agfl_bno[be32_to_cpu(agf->agf_flfirst)]); + be32_add_cpu(&agf->agf_flfirst, 1); + xfs_trans_brelse(tp, agflbp); + if (be32_to_cpu(agf->agf_flfirst) == XFS_AGFL_SIZE(mp)) + agf->agf_flfirst = 0; + + pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno)); + be32_add_cpu(&agf->agf_flcount, -1); + xfs_trans_agflist_delta(tp, -1); + pag->pagf_flcount--; + xfs_perag_put(pag); + + logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT; + if (btreeblk) { + be32_add_cpu(&agf->agf_btreeblks, 1); + pag->pagf_btreeblks++; + logflags |= XFS_AGF_BTREEBLKS; + } + + xfs_alloc_log_agf(tp, agbp, logflags); + *bnop = bno; + + return 0; +} + +/* + * Log the given fields from the agf structure. + */ +void +xfs_alloc_log_agf( + xfs_trans_t *tp, /* transaction pointer */ + xfs_buf_t *bp, /* buffer for a.g. freelist header */ + int fields) /* mask of fields to be logged (XFS_AGF_...) */ +{ + int first; /* first byte offset */ + int last; /* last byte offset */ + static const short offsets[] = { + offsetof(xfs_agf_t, agf_magicnum), + offsetof(xfs_agf_t, agf_versionnum), + offsetof(xfs_agf_t, agf_seqno), + offsetof(xfs_agf_t, agf_length), + offsetof(xfs_agf_t, agf_roots[0]), + offsetof(xfs_agf_t, agf_levels[0]), + offsetof(xfs_agf_t, agf_flfirst), + offsetof(xfs_agf_t, agf_fllast), + offsetof(xfs_agf_t, agf_flcount), + offsetof(xfs_agf_t, agf_freeblks), + offsetof(xfs_agf_t, agf_longest), + offsetof(xfs_agf_t, agf_btreeblks), + sizeof(xfs_agf_t) + }; + + trace_xfs_agf(tp->t_mountp, XFS_BUF_TO_AGF(bp), fields, _RET_IP_); + + xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last); + xfs_trans_log_buf(tp, bp, (uint)first, (uint)last); +} + +/* + * Interface for inode allocation to force the pag data to be initialized. + */ +int /* error */ +xfs_alloc_pagf_init( + xfs_mount_t *mp, /* file system mount structure */ + xfs_trans_t *tp, /* transaction pointer */ + xfs_agnumber_t agno, /* allocation group number */ + int flags) /* XFS_ALLOC_FLAGS_... */ +{ + xfs_buf_t *bp; + int error; + + if ((error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp))) + return error; + if (bp) + xfs_trans_brelse(tp, bp); + return 0; +} + +/* + * Put the block on the freelist for the allocation group. + */ +int /* error */ +xfs_alloc_put_freelist( + xfs_trans_t *tp, /* transaction pointer */ + xfs_buf_t *agbp, /* buffer for a.g. freelist header */ + xfs_buf_t *agflbp,/* buffer for a.g. free block array */ + xfs_agblock_t bno, /* block being freed */ + int btreeblk) /* block came from a AGF btree */ +{ + xfs_agf_t *agf; /* a.g. freespace structure */ + xfs_agfl_t *agfl; /* a.g. free block array */ + __be32 *blockp;/* pointer to array entry */ + int error; + int logflags; + xfs_mount_t *mp; /* mount structure */ + xfs_perag_t *pag; /* per allocation group data */ + + agf = XFS_BUF_TO_AGF(agbp); + mp = tp->t_mountp; + + if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp, + be32_to_cpu(agf->agf_seqno), &agflbp))) + return error; + agfl = XFS_BUF_TO_AGFL(agflbp); + be32_add_cpu(&agf->agf_fllast, 1); + if (be32_to_cpu(agf->agf_fllast) == XFS_AGFL_SIZE(mp)) + agf->agf_fllast = 0; + + pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno)); + be32_add_cpu(&agf->agf_flcount, 1); + xfs_trans_agflist_delta(tp, 1); + pag->pagf_flcount++; + + logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT; + if (btreeblk) { + be32_add_cpu(&agf->agf_btreeblks, -1); + pag->pagf_btreeblks--; + logflags |= XFS_AGF_BTREEBLKS; + } + xfs_perag_put(pag); + + xfs_alloc_log_agf(tp, agbp, logflags); + + ASSERT(be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp)); + blockp = &agfl->agfl_bno[be32_to_cpu(agf->agf_fllast)]; + *blockp = cpu_to_be32(bno); + xfs_alloc_log_agf(tp, agbp, logflags); + xfs_trans_log_buf(tp, agflbp, + (int)((xfs_caddr_t)blockp - (xfs_caddr_t)agfl), + (int)((xfs_caddr_t)blockp - (xfs_caddr_t)agfl + + sizeof(xfs_agblock_t) - 1)); + return 0; +} + +/* + * Read in the allocation group header (free/alloc section). + */ +int /* error */ +xfs_read_agf( + struct xfs_mount *mp, /* mount point structure */ + struct xfs_trans *tp, /* transaction pointer */ + xfs_agnumber_t agno, /* allocation group number */ + int flags, /* XFS_BUF_ */ + struct xfs_buf **bpp) /* buffer for the ag freelist header */ +{ + struct xfs_agf *agf; /* ag freelist header */ + int agf_ok; /* set if agf is consistent */ + int error; + + ASSERT(agno != NULLAGNUMBER); + error = xfs_trans_read_buf( + mp, tp, mp->m_ddev_targp, + XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)), + XFS_FSS_TO_BB(mp, 1), flags, bpp); + if (error) + return error; + if (!*bpp) + return 0; + + ASSERT(!(*bpp)->b_error); + agf = XFS_BUF_TO_AGF(*bpp); + + /* + * Validate the magic number of the agf block. + */ + agf_ok = + agf->agf_magicnum == cpu_to_be32(XFS_AGF_MAGIC) && + XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) && + be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) && + be32_to_cpu(agf->agf_flfirst) < XFS_AGFL_SIZE(mp) && + be32_to_cpu(agf->agf_fllast) < XFS_AGFL_SIZE(mp) && + be32_to_cpu(agf->agf_flcount) <= XFS_AGFL_SIZE(mp) && + be32_to_cpu(agf->agf_seqno) == agno; + if (xfs_sb_version_haslazysbcount(&mp->m_sb)) + agf_ok = agf_ok && be32_to_cpu(agf->agf_btreeblks) <= + be32_to_cpu(agf->agf_length); + if (unlikely(XFS_TEST_ERROR(!agf_ok, mp, XFS_ERRTAG_ALLOC_READ_AGF, + XFS_RANDOM_ALLOC_READ_AGF))) { + XFS_CORRUPTION_ERROR("xfs_alloc_read_agf", + XFS_ERRLEVEL_LOW, mp, agf); + xfs_trans_brelse(tp, *bpp); + return XFS_ERROR(EFSCORRUPTED); + } + xfs_buf_set_ref(*bpp, XFS_AGF_REF); + return 0; +} + +/* + * Read in the allocation group header (free/alloc section). + */ +int /* error */ +xfs_alloc_read_agf( + struct xfs_mount *mp, /* mount point structure */ + struct xfs_trans *tp, /* transaction pointer */ + xfs_agnumber_t agno, /* allocation group number */ + int flags, /* XFS_ALLOC_FLAG_... */ + struct xfs_buf **bpp) /* buffer for the ag freelist header */ +{ + struct xfs_agf *agf; /* ag freelist header */ + struct xfs_perag *pag; /* per allocation group data */ + int error; + + ASSERT(agno != NULLAGNUMBER); + + error = xfs_read_agf(mp, tp, agno, + (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0, + bpp); + if (error) + return error; + if (!*bpp) + return 0; + ASSERT(!(*bpp)->b_error); + + agf = XFS_BUF_TO_AGF(*bpp); + pag = xfs_perag_get(mp, agno); + if (!pag->pagf_init) { + pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks); + pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks); + pag->pagf_flcount = be32_to_cpu(agf->agf_flcount); + pag->pagf_longest = be32_to_cpu(agf->agf_longest); + pag->pagf_levels[XFS_BTNUM_BNOi] = + be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]); + pag->pagf_levels[XFS_BTNUM_CNTi] = + be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]); + spin_lock_init(&pag->pagb_lock); + pag->pagb_count = 0; + pag->pagb_tree = RB_ROOT; + pag->pagf_init = 1; + } +#ifdef DEBUG + else if (!XFS_FORCED_SHUTDOWN(mp)) { + ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks)); + ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks)); + ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount)); + ASSERT(pag->pagf_longest == be32_to_cpu(agf->agf_longest)); + ASSERT(pag->pagf_levels[XFS_BTNUM_BNOi] == + be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi])); + ASSERT(pag->pagf_levels[XFS_BTNUM_CNTi] == + be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi])); + } +#endif + xfs_perag_put(pag); + return 0; +} + +/* + * Allocate an extent (variable-size). + * Depending on the allocation type, we either look in a single allocation + * group or loop over the allocation groups to find the result. + */ +int /* error */ +__xfs_alloc_vextent( + xfs_alloc_arg_t *args) /* allocation argument structure */ +{ + xfs_agblock_t agsize; /* allocation group size */ + int error; + int flags; /* XFS_ALLOC_FLAG_... locking flags */ + xfs_extlen_t minleft;/* minimum left value, temp copy */ + xfs_mount_t *mp; /* mount structure pointer */ + xfs_agnumber_t sagno; /* starting allocation group number */ + xfs_alloctype_t type; /* input allocation type */ + int bump_rotor = 0; + int no_min = 0; + xfs_agnumber_t rotorstep = xfs_rotorstep; /* inode32 agf stepper */ + + mp = args->mp; + type = args->otype = args->type; + args->agbno = NULLAGBLOCK; + /* + * Just fix this up, for the case where the last a.g. is shorter + * (or there's only one a.g.) and the caller couldn't easily figure + * that out (xfs_bmap_alloc). + */ + agsize = mp->m_sb.sb_agblocks; + if (args->maxlen > agsize) + args->maxlen = agsize; + if (args->alignment == 0) + args->alignment = 1; + ASSERT(XFS_FSB_TO_AGNO(mp, args->fsbno) < mp->m_sb.sb_agcount); + ASSERT(XFS_FSB_TO_AGBNO(mp, args->fsbno) < agsize); + ASSERT(args->minlen <= args->maxlen); + ASSERT(args->minlen <= agsize); + ASSERT(args->mod < args->prod); + if (XFS_FSB_TO_AGNO(mp, args->fsbno) >= mp->m_sb.sb_agcount || + XFS_FSB_TO_AGBNO(mp, args->fsbno) >= agsize || + args->minlen > args->maxlen || args->minlen > agsize || + args->mod >= args->prod) { + args->fsbno = NULLFSBLOCK; + trace_xfs_alloc_vextent_badargs(args); + return 0; + } + minleft = args->minleft; + + switch (type) { + case XFS_ALLOCTYPE_THIS_AG: + case XFS_ALLOCTYPE_NEAR_BNO: + case XFS_ALLOCTYPE_THIS_BNO: + /* + * These three force us into a single a.g. + */ + args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno); + args->pag = xfs_perag_get(mp, args->agno); + args->minleft = 0; + error = xfs_alloc_fix_freelist(args, 0); + args->minleft = minleft; + if (error) { + trace_xfs_alloc_vextent_nofix(args); + goto error0; + } + if (!args->agbp) { + trace_xfs_alloc_vextent_noagbp(args); + break; + } + args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno); + if ((error = xfs_alloc_ag_vextent(args))) + goto error0; + break; + case XFS_ALLOCTYPE_START_BNO: + /* + * Try near allocation first, then anywhere-in-ag after + * the first a.g. fails. + */ + if ((args->userdata == XFS_ALLOC_INITIAL_USER_DATA) && + (mp->m_flags & XFS_MOUNT_32BITINODES)) { + args->fsbno = XFS_AGB_TO_FSB(mp, + ((mp->m_agfrotor / rotorstep) % + mp->m_sb.sb_agcount), 0); + bump_rotor = 1; + } + args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno); + args->type = XFS_ALLOCTYPE_NEAR_BNO; + /* FALLTHROUGH */ + case XFS_ALLOCTYPE_ANY_AG: + case XFS_ALLOCTYPE_START_AG: + case XFS_ALLOCTYPE_FIRST_AG: + /* + * Rotate through the allocation groups looking for a winner. + */ + if (type == XFS_ALLOCTYPE_ANY_AG) { + /* + * Start with the last place we left off. + */ + args->agno = sagno = (mp->m_agfrotor / rotorstep) % + mp->m_sb.sb_agcount; + args->type = XFS_ALLOCTYPE_THIS_AG; + flags = XFS_ALLOC_FLAG_TRYLOCK; + } else if (type == XFS_ALLOCTYPE_FIRST_AG) { + /* + * Start with allocation group given by bno. + */ + args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno); + args->type = XFS_ALLOCTYPE_THIS_AG; + sagno = 0; + flags = 0; + } else { + if (type == XFS_ALLOCTYPE_START_AG) + args->type = XFS_ALLOCTYPE_THIS_AG; + /* + * Start with the given allocation group. + */ + args->agno = sagno = XFS_FSB_TO_AGNO(mp, args->fsbno); + flags = XFS_ALLOC_FLAG_TRYLOCK; + } + /* + * Loop over allocation groups twice; first time with + * trylock set, second time without. + */ + for (;;) { + args->pag = xfs_perag_get(mp, args->agno); + if (no_min) args->minleft = 0; + error = xfs_alloc_fix_freelist(args, flags); + args->minleft = minleft; + if (error) { + trace_xfs_alloc_vextent_nofix(args); + goto error0; + } + /* + * If we get a buffer back then the allocation will fly. + */ + if (args->agbp) { + if ((error = xfs_alloc_ag_vextent(args))) + goto error0; + break; + } + + trace_xfs_alloc_vextent_loopfailed(args); + + /* + * Didn't work, figure out the next iteration. + */ + if (args->agno == sagno && + type == XFS_ALLOCTYPE_START_BNO) + args->type = XFS_ALLOCTYPE_THIS_AG; + /* + * For the first allocation, we can try any AG to get + * space. However, if we already have allocated a + * block, we don't want to try AGs whose number is below + * sagno. Otherwise, we may end up with out-of-order + * locking of AGF, which might cause deadlock. + */ + if (++(args->agno) == mp->m_sb.sb_agcount) { + if (args->firstblock != NULLFSBLOCK) + args->agno = sagno; + else + args->agno = 0; + } + /* + * Reached the starting a.g., must either be done + * or switch to non-trylock mode. + */ + if (args->agno == sagno) { + if (no_min == 1) { + args->agbno = NULLAGBLOCK; + trace_xfs_alloc_vextent_allfailed(args); + break; + } + if (flags == 0) { + no_min = 1; + } else { + flags = 0; + if (type == XFS_ALLOCTYPE_START_BNO) { + args->agbno = XFS_FSB_TO_AGBNO(mp, + args->fsbno); + args->type = XFS_ALLOCTYPE_NEAR_BNO; + } + } + } + xfs_perag_put(args->pag); + } + if (bump_rotor || (type == XFS_ALLOCTYPE_ANY_AG)) { + if (args->agno == sagno) + mp->m_agfrotor = (mp->m_agfrotor + 1) % + (mp->m_sb.sb_agcount * rotorstep); + else + mp->m_agfrotor = (args->agno * rotorstep + 1) % + (mp->m_sb.sb_agcount * rotorstep); + } + break; + default: + ASSERT(0); + /* NOTREACHED */ + } + if (args->agbno == NULLAGBLOCK) + args->fsbno = NULLFSBLOCK; + else { + args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno); +#ifdef DEBUG + ASSERT(args->len >= args->minlen); + ASSERT(args->len <= args->maxlen); + ASSERT(args->agbno % args->alignment == 0); + XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno), + args->len); +#endif + } + xfs_perag_put(args->pag); + return 0; +error0: + xfs_perag_put(args->pag); + return error; +} + +static void +xfs_alloc_vextent_worker( + struct work_struct *work) +{ + struct xfs_alloc_arg *args = container_of(work, + struct xfs_alloc_arg, work); + unsigned long pflags; + + /* we are in a transaction context here */ + current_set_flags_nested(&pflags, PF_FSTRANS); + + args->result = __xfs_alloc_vextent(args); + complete(args->done); + + current_restore_flags_nested(&pflags, PF_FSTRANS); +} + + +int /* error */ +xfs_alloc_vextent( + xfs_alloc_arg_t *args) /* allocation argument structure */ +{ + DECLARE_COMPLETION_ONSTACK(done); + + args->done = &done; + INIT_WORK(&args->work, xfs_alloc_vextent_worker); + queue_work(xfs_alloc_wq, &args->work); + wait_for_completion(&done); + return args->result; +} + +/* + * Free an extent. + * Just break up the extent address and hand off to xfs_free_ag_extent + * after fixing up the freelist. + */ +int /* error */ +xfs_free_extent( + xfs_trans_t *tp, /* transaction pointer */ + xfs_fsblock_t bno, /* starting block number of extent */ + xfs_extlen_t len) /* length of extent */ +{ + xfs_alloc_arg_t args; + int error; + + ASSERT(len != 0); + memset(&args, 0, sizeof(xfs_alloc_arg_t)); + args.tp = tp; + args.mp = tp->t_mountp; + + /* + * validate that the block number is legal - the enables us to detect + * and handle a silent filesystem corruption rather than crashing. + */ + args.agno = XFS_FSB_TO_AGNO(args.mp, bno); + if (args.agno >= args.mp->m_sb.sb_agcount) + return EFSCORRUPTED; + + args.agbno = XFS_FSB_TO_AGBNO(args.mp, bno); + if (args.agbno >= args.mp->m_sb.sb_agblocks) + return EFSCORRUPTED; + + args.pag = xfs_perag_get(args.mp, args.agno); + ASSERT(args.pag); + + error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING); + if (error) + goto error0; + + /* validate the extent size is legal now we have the agf locked */ + if (args.agbno + len > + be32_to_cpu(XFS_BUF_TO_AGF(args.agbp)->agf_length)) { + error = EFSCORRUPTED; + goto error0; + } + + error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0); + if (!error) + xfs_alloc_busy_insert(tp, args.agno, args.agbno, len, 0); +error0: + xfs_perag_put(args.pag); + return error; +} + +void +xfs_alloc_busy_insert( + struct xfs_trans *tp, + xfs_agnumber_t agno, + xfs_agblock_t bno, + xfs_extlen_t len, + unsigned int flags) +{ + struct xfs_busy_extent *new; + struct xfs_busy_extent *busyp; + struct xfs_perag *pag; + struct rb_node **rbp; + struct rb_node *parent = NULL; + + new = kmem_zalloc(sizeof(struct xfs_busy_extent), KM_MAYFAIL); + if (!new) { + /* + * No Memory! Since it is now not possible to track the free + * block, make this a synchronous transaction to insure that + * the block is not reused before this transaction commits. + */ + trace_xfs_alloc_busy_enomem(tp->t_mountp, agno, bno, len); + xfs_trans_set_sync(tp); + return; + } + + new->agno = agno; + new->bno = bno; + new->length = len; + INIT_LIST_HEAD(&new->list); + new->flags = flags; + + /* trace before insert to be able to see failed inserts */ + trace_xfs_alloc_busy(tp->t_mountp, agno, bno, len); + + pag = xfs_perag_get(tp->t_mountp, new->agno); + spin_lock(&pag->pagb_lock); + rbp = &pag->pagb_tree.rb_node; + while (*rbp) { + parent = *rbp; + busyp = rb_entry(parent, struct xfs_busy_extent, rb_node); + + if (new->bno < busyp->bno) { + rbp = &(*rbp)->rb_left; + ASSERT(new->bno + new->length <= busyp->bno); + } else if (new->bno > busyp->bno) { + rbp = &(*rbp)->rb_right; + ASSERT(bno >= busyp->bno + busyp->length); + } else { + ASSERT(0); + } + } + + rb_link_node(&new->rb_node, parent, rbp); + rb_insert_color(&new->rb_node, &pag->pagb_tree); + + list_add(&new->list, &tp->t_busy); + spin_unlock(&pag->pagb_lock); + xfs_perag_put(pag); +} + +/* + * Search for a busy extent within the range of the extent we are about to + * allocate. You need to be holding the busy extent tree lock when calling + * xfs_alloc_busy_search(). This function returns 0 for no overlapping busy + * extent, -1 for an overlapping but not exact busy extent, and 1 for an exact + * match. This is done so that a non-zero return indicates an overlap that + * will require a synchronous transaction, but it can still be + * used to distinguish between a partial or exact match. + */ +int +xfs_alloc_busy_search( + struct xfs_mount *mp, + xfs_agnumber_t agno, + xfs_agblock_t bno, + xfs_extlen_t len) +{ + struct xfs_perag *pag; + struct rb_node *rbp; + struct xfs_busy_extent *busyp; + int match = 0; + + pag = xfs_perag_get(mp, agno); + spin_lock(&pag->pagb_lock); + + rbp = pag->pagb_tree.rb_node; + + /* find closest start bno overlap */ + while (rbp) { + busyp = rb_entry(rbp, struct xfs_busy_extent, rb_node); + if (bno < busyp->bno) { + /* may overlap, but exact start block is lower */ + if (bno + len > busyp->bno) + match = -1; + rbp = rbp->rb_left; + } else if (bno > busyp->bno) { + /* may overlap, but exact start block is higher */ + if (bno < busyp->bno + busyp->length) + match = -1; + rbp = rbp->rb_right; + } else { + /* bno matches busyp, length determines exact match */ + match = (busyp->length == len) ? 1 : -1; + break; + } + } + spin_unlock(&pag->pagb_lock); + xfs_perag_put(pag); + return match; +} + +/* + * The found free extent [fbno, fend] overlaps part or all of the given busy + * extent. If the overlap covers the beginning, the end, or all of the busy + * extent, the overlapping portion can be made unbusy and used for the + * allocation. We can't split a busy extent because we can't modify a + * transaction/CIL context busy list, but we can update an entries block + * number or length. + * + * Returns true if the extent can safely be reused, or false if the search + * needs to be restarted. + */ +STATIC bool +xfs_alloc_busy_update_extent( + struct xfs_mount *mp, + struct xfs_perag *pag, + struct xfs_busy_extent *busyp, + xfs_agblock_t fbno, + xfs_extlen_t flen, + bool userdata) +{ + xfs_agblock_t fend = fbno + flen; + xfs_agblock_t bbno = busyp->bno; + xfs_agblock_t bend = bbno + busyp->length; + + /* + * This extent is currently being discarded. Give the thread + * performing the discard a chance to mark the extent unbusy + * and retry. + */ + if (busyp->flags & XFS_ALLOC_BUSY_DISCARDED) { + spin_unlock(&pag->pagb_lock); + delay(1); + spin_lock(&pag->pagb_lock); + return false; + } + + /* + * If there is a busy extent overlapping a user allocation, we have + * no choice but to force the log and retry the search. + * + * Fortunately this does not happen during normal operation, but + * only if the filesystem is very low on space and has to dip into + * the AGFL for normal allocations. + */ + if (userdata) + goto out_force_log; + + if (bbno < fbno && bend > fend) { + /* + * Case 1: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +---------+ + * fbno fend + */ + + /* + * We would have to split the busy extent to be able to track + * it correct, which we cannot do because we would have to + * modify the list of busy extents attached to the transaction + * or CIL context, which is immutable. + * + * Force out the log to clear the busy extent and retry the + * search. + */ + goto out_force_log; + } else if (bbno >= fbno && bend <= fend) { + /* + * Case 2: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +-----------------+ + * fbno fend + * + * Case 3: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +--------------------------+ + * fbno fend + * + * Case 4: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +--------------------------+ + * fbno fend + * + * Case 5: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +-----------------------------------+ + * fbno fend + * + */ + + /* + * The busy extent is fully covered by the extent we are + * allocating, and can simply be removed from the rbtree. + * However we cannot remove it from the immutable list + * tracking busy extents in the transaction or CIL context, + * so set the length to zero to mark it invalid. + * + * We also need to restart the busy extent search from the + * tree root, because erasing the node can rearrange the + * tree topology. + */ + rb_erase(&busyp->rb_node, &pag->pagb_tree); + busyp->length = 0; + return false; + } else if (fend < bend) { + /* + * Case 6: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +---------+ + * fbno fend + * + * Case 7: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +------------------+ + * fbno fend + * + */ + busyp->bno = fend; + } else if (bbno < fbno) { + /* + * Case 8: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +-------------+ + * fbno fend + * + * Case 9: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +----------------------+ + * fbno fend + */ + busyp->length = fbno - busyp->bno; + } else { + ASSERT(0); + } + + trace_xfs_alloc_busy_reuse(mp, pag->pag_agno, fbno, flen); + return true; + +out_force_log: + spin_unlock(&pag->pagb_lock); + xfs_log_force(mp, XFS_LOG_SYNC); + trace_xfs_alloc_busy_force(mp, pag->pag_agno, fbno, flen); + spin_lock(&pag->pagb_lock); + return false; +} + + +/* + * For a given extent [fbno, flen], make sure we can reuse it safely. + */ +void +xfs_alloc_busy_reuse( + struct xfs_mount *mp, + xfs_agnumber_t agno, + xfs_agblock_t fbno, + xfs_extlen_t flen, + bool userdata) +{ + struct xfs_perag *pag; + struct rb_node *rbp; + + ASSERT(flen > 0); + + pag = xfs_perag_get(mp, agno); + spin_lock(&pag->pagb_lock); +restart: + rbp = pag->pagb_tree.rb_node; + while (rbp) { + struct xfs_busy_extent *busyp = + rb_entry(rbp, struct xfs_busy_extent, rb_node); + xfs_agblock_t bbno = busyp->bno; + xfs_agblock_t bend = bbno + busyp->length; + + if (fbno + flen <= bbno) { + rbp = rbp->rb_left; + continue; + } else if (fbno >= bend) { + rbp = rbp->rb_right; + continue; + } + + if (!xfs_alloc_busy_update_extent(mp, pag, busyp, fbno, flen, + userdata)) + goto restart; + } + spin_unlock(&pag->pagb_lock); + xfs_perag_put(pag); +} + +/* + * For a given extent [fbno, flen], search the busy extent list to find a + * subset of the extent that is not busy. If *rlen is smaller than + * args->minlen no suitable extent could be found, and the higher level + * code needs to force out the log and retry the allocation. + */ +STATIC void +xfs_alloc_busy_trim( + struct xfs_alloc_arg *args, + xfs_agblock_t bno, + xfs_extlen_t len, + xfs_agblock_t *rbno, + xfs_extlen_t *rlen) +{ + xfs_agblock_t fbno; + xfs_extlen_t flen; + struct rb_node *rbp; + + ASSERT(len > 0); + + spin_lock(&args->pag->pagb_lock); +restart: + fbno = bno; + flen = len; + rbp = args->pag->pagb_tree.rb_node; + while (rbp && flen >= args->minlen) { + struct xfs_busy_extent *busyp = + rb_entry(rbp, struct xfs_busy_extent, rb_node); + xfs_agblock_t fend = fbno + flen; + xfs_agblock_t bbno = busyp->bno; + xfs_agblock_t bend = bbno + busyp->length; + + if (fend <= bbno) { + rbp = rbp->rb_left; + continue; + } else if (fbno >= bend) { + rbp = rbp->rb_right; + continue; + } + + /* + * If this is a metadata allocation, try to reuse the busy + * extent instead of trimming the allocation. + */ + if (!args->userdata && + !(busyp->flags & XFS_ALLOC_BUSY_DISCARDED)) { + if (!xfs_alloc_busy_update_extent(args->mp, args->pag, + busyp, fbno, flen, + false)) + goto restart; + continue; + } + + if (bbno <= fbno) { + /* start overlap */ + + /* + * Case 1: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +---------+ + * fbno fend + * + * Case 2: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +-------------+ + * fbno fend + * + * Case 3: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +-------------+ + * fbno fend + * + * Case 4: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +-----------------+ + * fbno fend + * + * No unbusy region in extent, return failure. + */ + if (fend <= bend) + goto fail; + + /* + * Case 5: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +----------------------+ + * fbno fend + * + * Case 6: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +--------------------------+ + * fbno fend + * + * Needs to be trimmed to: + * +-------+ + * fbno fend + */ + fbno = bend; + } else if (bend >= fend) { + /* end overlap */ + + /* + * Case 7: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +------------------+ + * fbno fend + * + * Case 8: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +--------------------------+ + * fbno fend + * + * Needs to be trimmed to: + * +-------+ + * fbno fend + */ + fend = bbno; + } else { + /* middle overlap */ + + /* + * Case 9: + * bbno bend + * +BBBBBBBBBBBBBBBBB+ + * +-----------------------------------+ + * fbno fend + * + * Can be trimmed to: + * +-------+ OR +-------+ + * fbno fend fbno fend + * + * Backward allocation leads to significant + * fragmentation of directories, which degrades + * directory performance, therefore we always want to + * choose the option that produces forward allocation + * patterns. + * Preferring the lower bno extent will make the next + * request use "fend" as the start of the next + * allocation; if the segment is no longer busy at + * that point, we'll get a contiguous allocation, but + * even if it is still busy, we will get a forward + * allocation. + * We try to avoid choosing the segment at "bend", + * because that can lead to the next allocation + * taking the segment at "fbno", which would be a + * backward allocation. We only use the segment at + * "fbno" if it is much larger than the current + * requested size, because in that case there's a + * good chance subsequent allocations will be + * contiguous. + */ + if (bbno - fbno >= args->maxlen) { + /* left candidate fits perfect */ + fend = bbno; + } else if (fend - bend >= args->maxlen * 4) { + /* right candidate has enough free space */ + fbno = bend; + } else if (bbno - fbno >= args->minlen) { + /* left candidate fits minimum requirement */ + fend = bbno; + } else { + goto fail; + } + } + + flen = fend - fbno; + } + spin_unlock(&args->pag->pagb_lock); + + if (fbno != bno || flen != len) { + trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len, + fbno, flen); + } + *rbno = fbno; + *rlen = flen; + return; +fail: + /* + * Return a zero extent length as failure indications. All callers + * re-check if the trimmed extent satisfies the minlen requirement. + */ + spin_unlock(&args->pag->pagb_lock); + trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len, fbno, 0); + *rbno = fbno; + *rlen = 0; +} + +static void +xfs_alloc_busy_clear_one( + struct xfs_mount *mp, + struct xfs_perag *pag, + struct xfs_busy_extent *busyp) +{ + if (busyp->length) { + trace_xfs_alloc_busy_clear(mp, busyp->agno, busyp->bno, + busyp->length); + rb_erase(&busyp->rb_node, &pag->pagb_tree); + } + + list_del_init(&busyp->list); + kmem_free(busyp); +} + +/* + * Remove all extents on the passed in list from the busy extents tree. + * If do_discard is set skip extents that need to be discarded, and mark + * these as undergoing a discard operation instead. + */ +void +xfs_alloc_busy_clear( + struct xfs_mount *mp, + struct list_head *list, + bool do_discard) +{ + struct xfs_busy_extent *busyp, *n; + struct xfs_perag *pag = NULL; + xfs_agnumber_t agno = NULLAGNUMBER; + + list_for_each_entry_safe(busyp, n, list, list) { + if (busyp->agno != agno) { + if (pag) { + spin_unlock(&pag->pagb_lock); + xfs_perag_put(pag); + } + pag = xfs_perag_get(mp, busyp->agno); + spin_lock(&pag->pagb_lock); + agno = busyp->agno; + } + + if (do_discard && busyp->length && + !(busyp->flags & XFS_ALLOC_BUSY_SKIP_DISCARD)) + busyp->flags = XFS_ALLOC_BUSY_DISCARDED; + else + xfs_alloc_busy_clear_one(mp, pag, busyp); + } + + if (pag) { + spin_unlock(&pag->pagb_lock); + xfs_perag_put(pag); + } +} + +/* + * Callback for list_sort to sort busy extents by the AG they reside in. + */ +int +xfs_busy_extent_ag_cmp( + void *priv, + struct list_head *a, + struct list_head *b) +{ + return container_of(a, struct xfs_busy_extent, list)->agno - + container_of(b, struct xfs_busy_extent, list)->agno; +} |