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xfs_alloc.c
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/*
* 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_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#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_search_busy(xfs_trans_t *tp,
xfs_agnumber_t agno,
xfs_agblock_t bno,
xfs_extlen_t len);
#if defined(XFS_ALLOC_TRACE)
ktrace_t *xfs_alloc_trace_buf;
#define TRACE_ALLOC(s,a) \
xfs_alloc_trace_alloc(fname, s, a, __LINE__)
#define TRACE_FREE(s,a,b,x,f) \
xfs_alloc_trace_free(fname, s, mp, a, b, x, f, __LINE__)
#define TRACE_MODAGF(s,a,f) \
xfs_alloc_trace_modagf(fname, s, mp, a, f, __LINE__)
#define TRACE_BUSY(fname,s,ag,agb,l,sl,tp) \
xfs_alloc_trace_busy(fname, s, mp, ag, agb, l, sl, tp, XFS_ALLOC_KTRACE_BUSY, __LINE__)
#define TRACE_UNBUSY(fname,s,ag,sl,tp) \
xfs_alloc_trace_busy(fname, s, mp, ag, -1, -1, sl, tp, XFS_ALLOC_KTRACE_UNBUSY, __LINE__)
#define TRACE_BUSYSEARCH(fname,s,ag,agb,l,sl,tp) \
xfs_alloc_trace_busy(fname, s, mp, ag, agb, l, sl, tp, XFS_ALLOC_KTRACE_BUSYSEARCH, __LINE__)
#else
#define TRACE_ALLOC(s,a)
#define TRACE_FREE(s,a,b,x,f)
#define TRACE_MODAGF(s,a,f)
#define TRACE_BUSY(s,a,ag,agb,l,sl,tp)
#define TRACE_UNBUSY(fname,s,ag,sl,tp)
#define TRACE_BUSYSEARCH(fname,s,ag,agb,l,sl,tp)
#endif /* XFS_ALLOC_TRACE */
/*
* Prototypes for per-ag allocation routines
*/
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 *);
/*
* Internal functions.
*/
/*
* Compute aligned version of the found extent.
* Takes alignment and min length into account.
*/
STATIC int /* success (>= minlen) */
xfs_alloc_compute_aligned(
xfs_agblock_t foundbno, /* starting block in found extent */
xfs_extlen_t foundlen, /* length in found extent */
xfs_extlen_t alignment, /* alignment for allocation */
xfs_extlen_t minlen, /* minimum length for allocation */
xfs_agblock_t *resbno, /* result block number */
xfs_extlen_t *reslen) /* result length */
{
xfs_agblock_t bno;
xfs_extlen_t diff;
xfs_extlen_t len;
if (alignment > 1 && foundlen >= minlen) {
bno = roundup(foundbno, alignment);
diff = bno - foundbno;
len = diff >= foundlen ? 0 : foundlen - diff;
} else {
bno = foundbno;
len = foundlen;
}
*resbno = bno;
*reslen = len;
return len >= minlen;
}
/*
* 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)
+ be32_to_cpu(agf->agf_flcount)
- 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
{
xfs_alloc_block_t *bnoblock;
xfs_alloc_block_t *cntblock;
if (bno_cur->bc_nlevels == 1 &&
cnt_cur->bc_nlevels == 1) {
bnoblock = XFS_BUF_TO_ALLOC_BLOCK(bno_cur->bc_bufs[0]);
cntblock = XFS_BUF_TO_ALLOC_BLOCK(cnt_cur->bc_bufs[0]);
XFS_WANT_CORRUPTED_RETURN(
be16_to_cpu(bnoblock->bb_numrecs) ==
be16_to_cpu(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_alloc_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_alloc_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_alloc_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_alloc_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_alloc_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(bp);
ASSERT(!XFS_BUF_GETERROR(bp));
XFS_BUF_SET_VTYPE_REF(bp, B_FS_AGFL, XFS_AGFL_REF);
*bpp = bp;
return 0;
}
#if defined(XFS_ALLOC_TRACE)
/*
* Add an allocation trace entry for an alloc call.
*/
STATIC void
xfs_alloc_trace_alloc(
char *name, /* function tag string */
char *str, /* additional string */
xfs_alloc_arg_t *args, /* allocation argument structure */
int line) /* source line number */
{
ktrace_enter(xfs_alloc_trace_buf,
(void *)(__psint_t)(XFS_ALLOC_KTRACE_ALLOC | (line << 16)),
(void *)name,
(void *)str,
(void *)args->mp,
(void *)(__psunsigned_t)args->agno,
(void *)(__psunsigned_t)args->agbno,
(void *)(__psunsigned_t)args->minlen,
(void *)(__psunsigned_t)args->maxlen,
(void *)(__psunsigned_t)args->mod,
(void *)(__psunsigned_t)args->prod,
(void *)(__psunsigned_t)args->minleft,
(void *)(__psunsigned_t)args->total,
(void *)(__psunsigned_t)args->alignment,
(void *)(__psunsigned_t)args->len,
(void *)((((__psint_t)args->type) << 16) |
(__psint_t)args->otype),
(void *)(__psint_t)((args->wasdel << 3) |
(args->wasfromfl << 2) |
(args->isfl << 1) |
(args->userdata << 0)));
}
/*
* Add an allocation trace entry for a free call.
*/
STATIC void
xfs_alloc_trace_free(
char *name, /* function tag string */
char *str, /* additional string */
xfs_mount_t *mp, /* file system mount point */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t agbno, /* a.g. relative block number */
xfs_extlen_t len, /* length of extent */
int isfl, /* set if is freelist allocation/free */
int line) /* source line number */
{
ktrace_enter(xfs_alloc_trace_buf,
(void *)(__psint_t)(XFS_ALLOC_KTRACE_FREE | (line << 16)),
(void *)name,
(void *)str,
(void *)mp,
(void *)(__psunsigned_t)agno,
(void *)(__psunsigned_t)agbno,
(void *)(__psunsigned_t)len,
(void *)(__psint_t)isfl,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
}
/*
* Add an allocation trace entry for modifying an agf.
*/
STATIC void
xfs_alloc_trace_modagf(
char *name, /* function tag string */
char *str, /* additional string */
xfs_mount_t *mp, /* file system mount point */
xfs_agf_t *agf, /* new agf value */
int flags, /* logging flags for agf */
int line) /* source line number */
{
ktrace_enter(xfs_alloc_trace_buf,
(void *)(__psint_t)(XFS_ALLOC_KTRACE_MODAGF | (line << 16)),
(void *)name,
(void *)str,
(void *)mp,
(void *)(__psint_t)flags,
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_seqno),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_length),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_roots[XFS_BTNUM_BNO]),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_roots[XFS_BTNUM_CNT]),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_flfirst),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_fllast),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_flcount),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_freeblks),
(void *)(__psunsigned_t)be32_to_cpu(agf->agf_longest));
}
STATIC void
xfs_alloc_trace_busy(
char *name, /* function tag string */
char *str, /* additional string */
xfs_mount_t *mp, /* file system mount point */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t agbno, /* a.g. relative block number */
xfs_extlen_t len, /* length of extent */
int slot, /* perag Busy slot */
xfs_trans_t *tp,
int trtype, /* type: add, delete, search */
int line) /* source line number */
{
ktrace_enter(xfs_alloc_trace_buf,
(void *)(__psint_t)(trtype | (line << 16)),
(void *)name,
(void *)str,
(void *)mp,
(void *)(__psunsigned_t)agno,
(void *)(__psunsigned_t)agbno,
(void *)(__psunsigned_t)len,
(void *)(__psint_t)slot,
(void *)tp,
NULL, NULL, NULL, NULL, NULL, NULL, NULL);
}
#endif /* XFS_ALLOC_TRACE */
/*
* 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;
#ifdef XFS_ALLOC_TRACE
static char fname[] = "xfs_alloc_ag_vextent";
#endif
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)
return error;
/*
* If the allocation worked, need to change the agf structure
* (and log it), and the superblock.
*/
if (args->agbno != NULLAGBLOCK) {
xfs_agf_t *agf; /* allocation group freelist header */
#ifdef XFS_ALLOC_TRACE
xfs_mount_t *mp = args->mp;
#endif
long slen = (long)args->len;
ASSERT(args->len >= args->minlen && args->len <= args->maxlen);
ASSERT(!(args->wasfromfl) || !args->isfl);
ASSERT(args->agbno % args->alignment == 0);
if (!(args->wasfromfl)) {
agf = XFS_BUF_TO_AGF(args->agbp);
be32_add(&agf->agf_freeblks, -(args->len));
xfs_trans_agblocks_delta(args->tp,
-((long)(args->len)));
args->pag->pagf_freeblks -= args->len;
ASSERT(be32_to_cpu(agf->agf_freeblks) <=
be32_to_cpu(agf->agf_length));
TRACE_MODAGF(NULL, agf, XFS_AGF_FREEBLKS);
xfs_alloc_log_agf(args->tp, args->agbp,
XFS_AGF_FREEBLKS);
/* search the busylist for these blocks */
xfs_alloc_search_busy(args->tp, 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, -slen);
XFS_STATS_INC(xs_allocx);
XFS_STATS_ADD(xs_allocb, args->len);
}
return 0;
}
/*
* 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 */
xfs_agblock_t end; /* end of allocated extent */
int error;
xfs_agblock_t fbno; /* start block of found extent */
xfs_agblock_t fend; /* end block of found extent */
xfs_extlen_t flen; /* length of found extent */
#ifdef XFS_ALLOC_TRACE
static char fname[] = "xfs_alloc_ag_vextent_exact";
#endif
int i; /* success/failure of operation */
xfs_agblock_t maxend; /* end of maximal extent */
xfs_agblock_t minend; /* end of minimal extent */
xfs_extlen_t rlen; /* length of returned extent */
ASSERT(args->alignment == 1);
/*
* Allocate/initialize a cursor for the by-number freespace btree.
*/
bno_cur = xfs_btree_init_cursor(args->mp, args->tp, args->agbp,
args->agno, XFS_BTNUM_BNO, NULL, 0);
/*
* 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.
*/
if ((error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i)))
goto error0;
if (!i) {
/*
* Didn't find it, return null.
*/
xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
args->agbno = NULLAGBLOCK;
return 0;
}
/*
* Grab the freespace record.
*/
if ((error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
ASSERT(fbno <= args->agbno);
minend = args->agbno + args->minlen;
maxend = args->agbno + args->maxlen;
fend = fbno + flen;
/*
* Give up if the freespace isn't long enough for the minimum request.
*/
if (fend < minend) {
xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
args->agbno = NULLAGBLOCK;
return 0;
}
/*
* End of extent will be smaller of the freespace end and the
* maximal requested end.
*/
end = XFS_AGBLOCK_MIN(fend, maxend);
/*
* Fix the length according to mod and prod if given.
*/
args->len = end - args->agbno;
xfs_alloc_fix_len(args);
if (!xfs_alloc_fix_minleft(args)) {
xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
return 0;
}
rlen = args->len;
ASSERT(args->agbno + rlen <= fend);
end = args->agbno + rlen;
/*
* We are allocating agbno for rlen [agbno .. end]
* Allocate/initialize a cursor for the by-size btree.
*/
cnt_cur = xfs_btree_init_cursor(args->mp, args->tp, args->agbp,
args->agno, XFS_BTNUM_CNT, NULL, 0);
ASSERT(args->agbno + args->len <=
be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
args->agbno, args->len, XFSA_FIXUP_BNO_OK))) {
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);
TRACE_ALLOC("normal", args);
args->wasfromfl = 0;
return 0;
error0:
xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
TRACE_ALLOC("error", args);
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 */
#ifdef XFS_ALLOC_TRACE
static char fname[] = "xfs_alloc_ag_vextent_near";
#endif
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 */
/*REFERENCED*/
xfs_agblock_t ltend; /* end bno of 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 */
#if defined(DEBUG) && defined(__KERNEL__)
/*
* Randomly don't execute the first algorithm.
*/
int dofirst; /* set to do first algorithm */
dofirst = random32() & 1;
#endif
/*
* Get a cursor for the by-size btree.
*/
cnt_cur = xfs_btree_init_cursor(args->mp, args->tp, args->agbp,
args->agno, XFS_BTNUM_CNT, NULL, 0);
ltlen = 0;
bno_cur_lt = bno_cur_gt = NULL;
/*
* 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);
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_alloc_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_alloc_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);
if (!xfs_alloc_compute_aligned(ltbno, ltlen,
args->alignment, args->minlen,
<bnoa, <lena))
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, ltbno, ltlen, <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);
ltend = ltbno + ltlen;
ASSERT(ltend <= 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_ALLOC("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 <= ltend);
/*
* Set up a cursor for the by-bno tree.
*/
bno_cur_lt = xfs_btree_init_cursor(args->mp, args->tp,
args->agbp, args->agno, XFS_BTNUM_BNO, NULL, 0);
/*
* 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_ALLOC("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_btree_init_cursor(args->mp, args->tp, args->agbp,
args->agno, XFS_BTNUM_BNO, NULL, 0);
/*
* 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_alloc_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);
if (xfs_alloc_compute_aligned(ltbno, ltlen,
args->alignment, args->minlen,
<bnoa, <lena))
break;
if ((error = xfs_alloc_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);
if (xfs_alloc_compute_aligned(gtbno, gtlen,
args->alignment, args->minlen,
>bnoa, >lena))
break;
if ((error = xfs_alloc_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.