#ident "$Revision: 1.42 $"
/*
* Free space allocation for xFS.
*/
#include <sys/param.h>
#ifdef SIM
#define _KERNEL
#endif
#include <sys/buf.h>
#ifdef SIM
#undef _KERNEL
#endif
#include <sys/vnode.h>
#include <sys/uuid.h>
#include <sys/debug.h>
#include <stddef.h>
#ifdef SIM
#include <stdlib.h>
#include <bstring.h>
#else
#include <sys/systm.h>
#endif
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_alloc_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#ifdef SIM
#include "sim.h"
#endif
#if !defined(SIM) || !defined(XFSDEBUG)
#define kmem_check() /* dummy for memory-allocation checking */
#endif
/*
* Prototypes for internal functions.
*/
/*
* Compute best start block and diff for "near" allocations.
* freelen >= wantlen already checked by caller.
*/
STATIC xfs_agblock_t /* difference value (absolute) */
xfs_alloc_compute_diff(
xfs_agblock_t wantbno, /* target starting block */
xfs_extlen_t wantlen, /* target length */
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 */
/*
* 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 xfs_extlen_t /* new length to use instead of len */
xfs_alloc_fix_len(
xfs_extlen_t mod, /* mod value to fix length with */
xfs_extlen_t prod, /* product value to fix length with */
xfs_extlen_t len, /* input length */
xfs_extlen_t minlen, /* minimum length */
xfs_extlen_t maxlen); /* maximum length */
/*
* Read in the allocation group header (free/alloc section).
*/
STATIC buf_t * /* buffer for the ag freelist header */
xfs_alloc_read_agf(
xfs_mount_t *mp, /* mount point structure */
xfs_trans_t *tp, /* transaction pointer */
xfs_agnumber_t agno, /* allocation group number */
int flags); /* XFS_ALLOC_FLAG_... */
/*
* Prototypes for per-ag allocation routines
*/
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t bno, /* allocation-group relative block number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_alloctype_t type, /* allocation type XFS_ALLOCTYPE_... */
int wasdel, /* set if allocation was previously delayed */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl); /* set if is freelist blocks - no sb acctg */
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent_exact(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t bno, /* allocation-group relative block number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl); /* set if is freelist blocks - no sb acctg */
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent_near(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t bno, /* allocation-group relative block number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl); /* set if is freelist blocks - no sb acctg */
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent_size(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl); /* set if is freelist blocks - no sb acctg */
/*
* Free the extent starting at agno/bno for length.
*/
STATIC int /* return success/failure, will be void */
xfs_free_ag_extent(
xfs_trans_t *tp, /* transaction pointer */
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 */
/*
* Internal functions.
*/
/*
* Compute best start block and diff for "near" allocations.
* freelen >= wantlen already checked by caller.
*/
STATIC xfs_agblock_t /* difference value (absolute) */
xfs_alloc_compute_diff(
xfs_agblock_t wantbno, /* target starting block */
xfs_extlen_t wantlen, /* target length */
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 newbno; /* return block number */
xfs_agblock_t wantend; /* end of target extent */
freeend = freebno + freelen;
wantend = wantbno + wantlen;
if (freebno >= wantbno)
newbno = freebno;
else if (freeend >= wantend)
newbno = wantbno;
else
newbno = freeend - wantlen;
*newbnop = newbno;
return newbno <= wantbno ? wantbno - newbno : newbno - 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 xfs_extlen_t /* new length to use instead of len */
xfs_alloc_fix_len(
xfs_extlen_t mod, /* mod value to fix length with */
xfs_extlen_t prod, /* product value to fix length with */
xfs_extlen_t len, /* input length */
xfs_extlen_t minlen, /* minimum length */
xfs_extlen_t maxlen) /* maximum length */
{
xfs_extlen_t k;
xfs_extlen_t rlen;
ASSERT(mod < prod);
ASSERT(len >= minlen);
ASSERT(len <= maxlen);
if (prod <= 1 || len < mod || len == maxlen || (mod == 0 && len < prod))
return len;
k = len % prod;
if (k == mod)
return len;
if (k > mod) {
if ((int)(rlen = len - k - mod) < (int)minlen)
return len;
} else {
if ((int)(rlen = len - prod - (mod - k)) < (int)minlen)
return len;
}
return rlen;
}
/*
* Read in the allocation group header (free/alloc section).
*/
STATIC buf_t * /* buffer for the ag freelist header */
xfs_alloc_read_agf(
xfs_mount_t *mp, /* mount point structure */
xfs_trans_t *tp, /* transaction pointer */
xfs_agnumber_t agno, /* allocation group number */
int flags) /* XFS_ALLOC_FLAG_... */
{
buf_t *bp; /* return value */
daddr_t d; /* disk block address */
ASSERT(agno != NULLAGNUMBER);
d = XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR);
bp = xfs_trans_read_buf(tp, mp->m_dev, d, 1,
(flags & XFS_ALLOC_FLAG_TRYLOCK) ? BUF_TRYLOCK : 0U);
ASSERT(!bp || !geterror(bp));
return bp;
}
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t bno, /* allocation-group relative block number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_alloctype_t type, /* allocation type XFS_ALLOCTYPE_... */
int wasdel, /* set if allocation was previously delayed */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl) /* set if is freelist blocks - no sb acctg */
{
xfs_agf_t *agf; /* allocation group freelist header */
xfs_agblock_t r; /* return value (starting block) */
ASSERT(minlen > 0 && maxlen > 0 && minlen <= maxlen);
ASSERT(mod < prod);
/*
* Branch to correct routine based on the type.
*/
switch (type) {
case XFS_ALLOCTYPE_THIS_AG:
r = xfs_alloc_ag_vextent_size(tp, agbp, agno, minlen, maxlen,
len, mod, prod, isfl);
break;
case XFS_ALLOCTYPE_NEAR_BNO:
r = xfs_alloc_ag_vextent_near(tp, agbp, agno, bno, minlen,
maxlen, len, mod, prod, isfl);
break;
case XFS_ALLOCTYPE_THIS_BNO:
r = xfs_alloc_ag_vextent_exact(tp, agbp, agno, bno, minlen,
maxlen, len, mod, prod, isfl);
break;
default:
ASSERT(0);
/* NOTREACHED */
}
/*
* If the allocation worked, need to change the agf structure
* (and log it), and the superblock.
*/
if (r != NULLAGBLOCK) {
int slen = (int)*len;
ASSERT(*len >= minlen && *len <= maxlen);
agf = XFS_BUF_TO_AGF(agbp);
agf->agf_freeblks -= *len;
xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
if (!isfl)
xfs_trans_mod_sb(tp,
wasdel ? XFS_TRANS_SB_RES_FDBLOCKS :
XFS_TRANS_SB_FDBLOCKS, -slen);
}
return r;
}
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent_exact(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t bno, /* allocation-group relative block number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl) /* set if is freelist blocks - no sb acctg */
{
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 */
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 */
xfs_agblock_t maxend; /* end of maximal extent */
xfs_agblock_t minend; /* end of minimal extent */
xfs_mount_t *mp; /* mount point structure for filesystem */
xfs_extlen_t rlen; /* requested extent length */
/*
* Allocate/initialize a cursor for the by-number freespace btree.
*/
mp = tp->t_mountp;
bno_cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO, 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 (!xfs_alloc_lookup_le(bno_cur, bno, minlen)) {
/*
* Didn't find it, return null.
*/
xfs_btree_del_cursor(bno_cur);
return NULLAGBLOCK;
}
/*
* Grab the freespace record.
*/
xfs_alloc_get_rec(bno_cur, &fbno, &flen);
ASSERT(fbno <= bno);
minend = bno + minlen;
maxend = bno + 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);
return NULLAGBLOCK;
}
/*
* 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.
*/
rlen = xfs_alloc_fix_len(mod, prod, end - bno, minlen, maxlen);
end = bno + rlen;
/*
* We are allocating bno for rlen [bno .. end)
*/
/*
* Allocate/initialize a cursor for the by-size btree.
*/
cnt_cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT, 0);
/*
* Look up the previously found extent.
*/
{
int i;
i = xfs_alloc_lookup_eq(cnt_cur, fbno, flen);
ASSERT(i == 1);
}
/*
* Delete the extent from the by-size btree.
*/
xfs_alloc_delete(cnt_cur);
/*
* If the found freespace starts left of the allocation, add back the
* leftover freespace to the by-size btree.
*/
if (fbno < bno) {
xfs_alloc_lookup_eq(cnt_cur, fbno, bno - fbno);
xfs_alloc_insert(cnt_cur);
}
/*
* If the found freespace ends right of the allocation, add back the
* leftover freespace to the by-size btree.
*/
if (fend > end) {
xfs_alloc_lookup_eq(cnt_cur, end, fend - end);
xfs_alloc_insert(cnt_cur);
}
xfs_alloc_rcheck(cnt_cur);
xfs_alloc_kcheck(cnt_cur);
xfs_btree_del_cursor(cnt_cur);
/*
* If the found freespace matches the allocation, just delete it
* from the by-bno btree.
*/
if (fbno == bno && fend == end)
xfs_alloc_delete(bno_cur);
/*
* If the found freespace starts at the same block but is longer,
* just update the by-bno btree entry to be shorter.
*/
else if (fbno == bno)
xfs_alloc_update(bno_cur, end, fend - end);
else {
/*
* If the found freespace starts left of the allocation,
* update the length of that by-bno entry.
*/
xfs_alloc_update(bno_cur, fbno, bno - fbno);
/*
* ... and if the found freespace ends right of the
* allocation, add another btree entry with the leftover space.
*/
if (fend > end) {
xfs_alloc_lookup_eq(bno_cur, end, fend - end);
xfs_alloc_insert(bno_cur);
}
}
*len = end - bno;
xfs_alloc_rcheck(bno_cur);
xfs_alloc_kcheck(bno_cur);
xfs_btree_del_cursor(bno_cur);
return bno;
}
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent_near(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_agblock_t bno, /* allocation-group relative block number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl) /* set if is freelist blocks - no sb acctg */
{
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_extlen_t gtdiff; /* difference to right side entry */
xfs_agblock_t gtend; /* end bno of right side entry */
xfs_extlen_t gtlen; /* length of right side entry */
xfs_agblock_t gtnew; /* useful start bno of right side */
xfs_agblock_t gtnewend; /* useful end bno of right side */
int i; /* result code, temporary */
xfs_agblock_t ltbno; /* start bno of left side entry */
xfs_extlen_t ltdiff; /* difference to left side entry */
xfs_agblock_t ltend; /* end bno of left side entry */
xfs_extlen_t ltlen; /* length of left side entry */
xfs_agblock_t ltnew; /* useful start bno of left side */
xfs_agblock_t ltnewend; /* useful end bno of left side */
xfs_mount_t *mp; /* mount point structure for filesys */
xfs_extlen_t rlen; /* length of allocated extent */
mp = tp->t_mountp;
/*
* Get a cursor for the by-size btree.
*/
cnt_cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT, 0);
ltlen = 0;
/*
* See if there are any free extents as big as maxlen.
*/
if (!xfs_alloc_lookup_ge(cnt_cur, 0, maxlen)) {
/*
* Nothing as big as maxlen.
* Is there anything at all in the tree?
* If so get the biggest extent.
*/
if (xfs_alloc_decrement(cnt_cur, 0))
xfs_alloc_get_rec(cnt_cur, <bno, <len);
/*
* Nothing in the tree, try the freelist.
*/
else if (minlen == 1 && !isfl &&
(ltbno = xfs_alloc_get_freelist(tp, agbp, NULL)) !=
NULLAGBLOCK) {
xfs_btree_del_cursor(cnt_cur);
*len = 1;
return ltbno;
}
/*
* If nothing, or what we got is too small, give up.
*/
if (ltlen < minlen) {
xfs_btree_del_cursor(cnt_cur);
return NULLAGBLOCK;
}
}
/*
* 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.
*/
if (xfs_btree_islastblock(cnt_cur, 0)) {
xfs_extlen_t bdiff;
int besti;
xfs_agblock_t bnew;
/*
* 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) {
ASSERT(ltlen >= minlen && ltlen < maxlen);
cnt_cur->bc_ptrs[0] = 1;
do {
xfs_alloc_get_rec(cnt_cur, <bno, <len);
if (ltlen >= minlen)
break;
} while (xfs_alloc_increment(cnt_cur, 0));
ASSERT(ltlen >= minlen);
}
i = cnt_cur->bc_ptrs[0];
besti = 0;
bdiff = ltdiff = (xfs_extlen_t)0;
do {
/*
* For each entry, decide if it's better than
* the previous best entry.
*/
xfs_alloc_get_rec(cnt_cur, <bno, <len);
rlen = XFS_EXTLEN_MIN(ltlen, maxlen);
rlen = xfs_alloc_fix_len(mod, prod, rlen, minlen,
maxlen);
ltdiff = xfs_alloc_compute_diff(bno, rlen, ltbno, ltlen,
<new);
if (!besti || ltdiff < bdiff) {
bdiff = ltdiff;
bnew = ltnew;
besti = i;
}
i++;
} while (ltdiff > 0 && xfs_alloc_increment(cnt_cur, 0));
/*
* Point at the best entry, and retrieve it again.
*/
cnt_cur->bc_ptrs[0] = besti;
xfs_alloc_get_rec(cnt_cur, <bno, <len);
ltend = ltbno + ltlen;
rlen = XFS_EXTLEN_MIN(ltlen, maxlen);
rlen = xfs_alloc_fix_len(mod, prod, rlen, minlen, maxlen);
/*
* Delete that entry from the by-size tree.
*/
xfs_alloc_delete(cnt_cur);
/*
* We are allocating starting at bnew for rlen blocks.
*/
ltnew = bnew;
ltnewend = bnew + rlen;
*len = rlen;
/*
* Set up a cursor for the by-bno tree.
*/
bno_cur_lt = xfs_btree_init_cursor(mp, tp, agbp, agno,
XFS_BTNUM_BNO, 0);
/*
* Find the entry we used.
*/
i = xfs_alloc_lookup_eq(bno_cur_lt, ltbno, ltlen);
ASSERT(i == 1);
/*
* Freespace properly contains allocated space.
*/
if (ltbno < ltnew && ltend > ltnewend) {
/*
* Insert two leftover entries into the cnt tree.
* Update the bno entry, and add a new one for the
* new (leftover on the right) freespace.
*/
xfs_alloc_lookup_eq(cnt_cur, ltbno, ltnew - ltbno);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur_lt, ltbno, ltnew - ltbno);
xfs_alloc_lookup_eq(cnt_cur, ltnewend,
ltend - ltnewend);
xfs_alloc_insert(cnt_cur);
xfs_alloc_lookup_eq(bno_cur_lt, ltnewend,
ltend - ltnewend);
xfs_alloc_insert(bno_cur_lt);
}
/*
* Freespace contains allocated space, matches at left side.
*/
else if (ltend > ltnewend) {
/*
* Insert the leftover entry for the cnt tree.
* Update the bno entry to have just the leftover space.
*/
xfs_alloc_lookup_eq(cnt_cur, ltnewend,
ltend - ltnewend);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur_lt, ltnewend,
ltend - ltnewend);
}
/*
* Freespace contains allocated space, matches at right side.
*/
else if (ltbno < ltnew) {
/*
* Insert the leftover entry for the cnt tree.
* Update the bno entry to have just the leftover space.
*/
xfs_alloc_lookup_eq(cnt_cur, ltbno, ltnew - ltbno);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur_lt, ltbno, ltnew - ltbno);
}
/*
* Freespace same size as allocated.
*/
else {
/*
* Just delete the bno tree entry.
*/
xfs_alloc_delete(bno_cur_lt);
}
xfs_alloc_rcheck(cnt_cur);
xfs_alloc_kcheck(cnt_cur);
xfs_btree_del_cursor(cnt_cur);
xfs_alloc_rcheck(bno_cur_lt);
xfs_alloc_kcheck(bno_cur_lt);
xfs_btree_del_cursor(bno_cur_lt);
return ltnew;
}
/*
* 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.
*/
/*
* Allocate and initialize the cursor for the leftward search.
*/
bno_cur_lt = xfs_btree_init_cursor(mp, tp, agbp, agno,
XFS_BTNUM_BNO, 0);
/*
* Lookup <= bno to find the leftward search's starting point.
*/
if (!xfs_alloc_lookup_le(bno_cur_lt, bno, maxlen)) {
/*
* Didn't find anything; use this cursor for the rightward
* search.
*/
bno_cur_gt = bno_cur_lt;
bno_cur_lt = 0;
}
/*
* Found something. Duplicate the cursor for the rightward search.
*/
else
bno_cur_gt = xfs_btree_dup_cursor(bno_cur_lt);
/*
* Increment the cursor, so we will point at the entry just right
* of the leftward entry if any, or to the leftmost entry.
*/
if (!xfs_alloc_increment(bno_cur_gt, 0)) {
/*
* It failed, there are no rightward entries.
*/
xfs_btree_del_cursor(bno_cur_gt);
bno_cur_gt = 0;
}
/*
* 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) {
xfs_alloc_get_rec(bno_cur_lt, <bno, <len);
if (ltlen >= minlen)
break;
if (!xfs_alloc_decrement(bno_cur_lt, 0)) {
xfs_btree_del_cursor(bno_cur_lt);
bno_cur_lt = 0;
}
}
if (bno_cur_gt) {
xfs_alloc_get_rec(bno_cur_gt, >bno, >len);
if (gtlen >= minlen)
break;
if (!xfs_alloc_increment(bno_cur_gt, 0)) {
xfs_btree_del_cursor(bno_cur_gt);
bno_cur_gt = 0;
}
}
} while (bno_cur_lt || bno_cur_gt);
/*
* We have to find something as big as minlen, we've already checked.
*/
ASSERT(bno_cur_lt || bno_cur_gt);
/*
* Got both cursors still active, need to find better entry.
*/
if (bno_cur_lt && bno_cur_gt) {
/*
* Left side is long enough, look for a right side entry.
*/
if (ltlen >= minlen) {
/*
* Fix up the length.
*/
rlen = XFS_EXTLEN_MIN(ltlen, maxlen);
rlen = xfs_alloc_fix_len(mod, prod, rlen, minlen,
maxlen);
ltdiff = xfs_alloc_compute_diff(bno, rlen, ltbno,
ltlen, <new);
/*
* Not perfect.
*/
if (ltdiff) {
/*
* Look until we find a better one, run out of
* space, or run off the end.
*/
while (bno_cur_lt && bno_cur_gt) {
xfs_alloc_get_rec(bno_cur_gt, >bno,
>len);
/*
* The left one is clearly better.
*/
if (gtbno >= bno + ltdiff) {
xfs_btree_del_cursor(
bno_cur_gt);
bno_cur_gt = 0;
break;
}
/*
* If we reach a big enough entry,
* compare the two and pick the best.
*/
if (gtlen >= minlen) {
rlen = XFS_EXTLEN_MIN(gtlen,
maxlen);
rlen = xfs_alloc_fix_len(mod,
prod, rlen, minlen,
maxlen);
gtdiff = xfs_alloc_compute_diff(
bno, rlen, gtbno, gtlen,
>new);
/*
* Right side is better.
*/
if (gtdiff < ltdiff) {
xfs_btree_del_cursor(
bno_cur_lt);
bno_cur_lt = 0;
}
/*
* Left side is better.
*/
else {
xfs_btree_del_cursor(
bno_cur_gt);
bno_cur_gt = 0;
}
break;
}
/*
* Fell off the right end.
*/
if (!xfs_alloc_increment(bno_cur_gt,
0)) {
xfs_btree_del_cursor(
bno_cur_gt);
bno_cur_gt = 0;
break;
}
}
}
/*
* The left side is perfect, trash the right side.
*/
else {
xfs_btree_del_cursor(bno_cur_gt);
bno_cur_gt = 0;
}
}
/*
* It's the right side that was found first, look left.
*/
else {
/*
* Fix up the length.
*/
rlen = XFS_EXTLEN_MIN(gtlen, maxlen);
rlen = xfs_alloc_fix_len(mod, prod, rlen, minlen,
maxlen);
gtdiff = xfs_alloc_compute_diff(bno, rlen, gtbno, gtlen,
>new);
/*
* Right side entry isn't perfect.
*/
if (gtdiff) {
/*
* Look until we find a better one, run out of
* space, or run off the end.
*/
while (bno_cur_lt && bno_cur_gt) {
xfs_alloc_get_rec(bno_cur_lt, <bno,
<len);
/*
* The right one is clearly better.
*/
if (ltbno <= bno - gtdiff) {
xfs_btree_del_cursor(
bno_cur_lt);
bno_cur_lt = 0;
break;
}
/*
* If we reach a big enough entry,
* compare the two and pick the best.
*/
if (ltlen >= minlen) {
rlen = XFS_EXTLEN_MIN(ltlen,
maxlen);
rlen = xfs_alloc_fix_len(mod,
prod, rlen, minlen,
maxlen);
ltdiff = xfs_alloc_compute_diff(
bno, rlen, ltbno, ltlen,
<new);
/*
* Left side is better.
*/
if (ltdiff < gtdiff) {
xfs_btree_del_cursor(
bno_cur_gt);
bno_cur_gt = 0;
}
/*
* Right side is better.
*/
else {
xfs_btree_del_cursor(
bno_cur_lt);
bno_cur_lt = 0;
}
break;
}
/*
* Fell off the left end.
*/
if (!xfs_alloc_decrement(bno_cur_lt,
0)) {
xfs_btree_del_cursor(
bno_cur_lt);
bno_cur_lt = 0;
break;
}
}
}
/*
* The right side is perfect, trash the left side.
*/
else {
xfs_btree_del_cursor(bno_cur_lt);
bno_cur_lt = 0;
}
}
}
/*
* At this point we have selected a freespace entry, either to the
* left or to the right.
*/
/*
* On the left side.
*/
if (bno_cur_lt) {
/*
* Fix up the length and compute the useful address.
*/
ltend = ltbno + ltlen;
rlen = XFS_EXTLEN_MIN(ltlen, maxlen);
rlen = xfs_alloc_fix_len(mod, prod, rlen, minlen, maxlen);
ltdiff = xfs_alloc_compute_diff(bno, rlen, ltbno, ltlen,
<new);
ltnewend = ltnew + rlen;
*len = rlen;
/*
* Find the equivalent by-size btree record and delete it.
*/
i = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen);
ASSERT(i == 1);
xfs_alloc_delete(cnt_cur);
/*
* Freespace properly contains allocated space.
* Insert two leftover by-size records.
* Update the by-block tree for the left leftover,
* and insert a new by-block record for the right leftover.
*/
if (ltbno < ltnew && ltend > ltnewend) {
xfs_alloc_lookup_eq(cnt_cur, ltbno, ltnew - ltbno);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur_lt, ltbno, ltnew - ltbno);
xfs_alloc_lookup_eq(cnt_cur, ltnewend, ltend - ltnewend);
xfs_alloc_insert(cnt_cur);
xfs_alloc_lookup_eq(bno_cur_lt, ltnewend, ltend - ltnewend);
xfs_alloc_insert(bno_cur_lt);
}
/*
* Freespace contains allocated space, matches at left side.
* Insert the right-side leftover in the by-size tree.
* Update the by-block record with the new length.
*/
else if (ltend > ltnewend) {
xfs_alloc_lookup_eq(cnt_cur, ltnewend, ltend - ltnewend);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur_lt, ltnewend, ltend - ltnewend);
}
/*
* Freespace contains allocated space, matches at right side.
* Insert the left-side leftover in the by-size tree.
* Update the by-block record with the new start/length.
*/
else if (ltbno < ltnew) {
xfs_alloc_lookup_eq(cnt_cur, ltbno, ltnew - ltbno);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur_lt, ltbno, ltnew - ltbno);
}
/*
* Freespace same size as allocated.
* Just delete everything.
*/
else
xfs_alloc_delete(bno_cur_lt);
xfs_alloc_rcheck(cnt_cur);
xfs_alloc_kcheck(cnt_cur);
xfs_btree_del_cursor(cnt_cur);
xfs_alloc_rcheck(bno_cur_lt);
xfs_alloc_kcheck(bno_cur_lt);
xfs_btree_del_cursor(bno_cur_lt);
return ltnew;
}
/*
* On the right side.
*/
else {
/*
* Fix up the length and compute the useful address.
*/
gtend = gtbno + gtlen;
rlen = XFS_EXTLEN_MIN(gtlen, maxlen);
rlen = xfs_alloc_fix_len(mod, prod, rlen, minlen, maxlen);
gtdiff = xfs_alloc_compute_diff(bno, rlen, gtbno, gtlen,
>new);
gtnewend = gtnew + rlen;
*len = rlen;
/*
* Find the equivalent by-size btree record and delete it.
*/
i = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen);
ASSERT(i == 1);
xfs_alloc_delete(cnt_cur);
/*
* Other cases can't occur since gtbno > bno.
*/
/*
* Freespace contains allocated space, matches at left side.
* Insert the right-side leftover in the by-size tree.
* Update the by-block record with the new length.
*/
if (gtend > gtnewend) {
xfs_alloc_lookup_eq(cnt_cur, gtnewend,
gtend - gtnewend);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur_gt, gtnewend,
gtend - gtnewend);
}
/*
* Freespace same size as allocated.
* Just delete everything.
*/
else
xfs_alloc_delete(bno_cur_gt);
xfs_alloc_rcheck(cnt_cur);
xfs_alloc_kcheck(cnt_cur);
xfs_btree_del_cursor(cnt_cur);
xfs_alloc_rcheck(bno_cur_gt);
xfs_alloc_kcheck(bno_cur_gt);
xfs_btree_del_cursor(bno_cur_gt);
return gtnew;
}
}
/*
* 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 xfs_agblock_t /* starting block number of allocated extent */
xfs_alloc_ag_vextent_size(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agnumber_t agno, /* allocation group number */
xfs_extlen_t minlen, /* mininum size of extent */
xfs_extlen_t maxlen, /* maximum size of extent */
xfs_extlen_t *len, /* output: size of extent */
xfs_extlen_t mod, /* mod value for extent size */
xfs_extlen_t prod, /* prod value for extent size */
int isfl) /* set if is freelist blocks - no sb acctg */
{
xfs_btree_cur_t *bno_cur; /* cursor for bno btree */
xfs_btree_cur_t *cnt_cur; /* cursor for cnt btree */
xfs_agblock_t fbno; /* start of found freespace */
xfs_extlen_t flen; /* length of found freespace */
xfs_mount_t *mp; /* mount point of filesystem */
xfs_extlen_t rlen; /* length of returned extent */
mp = tp->t_mountp;
/*
* Allocate and initialize a cursor for the by-size btree.
*/
cnt_cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT, 0);
/*
* Look for an entry >= maxlen blocks.
* If none, then pick up the last entry in the tree unless the
* tree is empty.
*/
if (!xfs_alloc_lookup_ge(cnt_cur, 0, maxlen)) {
if (xfs_alloc_decrement(cnt_cur, 0))
xfs_alloc_get_rec(cnt_cur, &fbno, &flen);
/*
* Nothing in the btree, try the freelist.
*/
else if (minlen == 1 && !isfl &&
(fbno = xfs_alloc_get_freelist(tp, agbp, NULL)) !=
NULLAGBLOCK) {
xfs_btree_del_cursor(cnt_cur);
*len = 1;
return fbno;
} else
flen = 0;
/*
* Nothing as big as minlen, give up.
*/
if (flen < minlen) {
xfs_btree_del_cursor(cnt_cur);
return NULLAGBLOCK;
}
rlen = flen;
}
/*
* There's a freespace as big as maxlen, get it.
*/
else {
xfs_alloc_get_rec(cnt_cur, &fbno, &flen);
rlen = maxlen;
}
/*
* Fix up the length.
*/
rlen = xfs_alloc_fix_len(mod, prod, rlen, minlen, maxlen);
/*
* Delete the entry from the by-size btree.
*/
xfs_alloc_delete(cnt_cur);
/*
* Allocate and initialize a cursor for the by-block tree.
* Look up the found space in that tree.
*/
bno_cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO, 0);
{
int i;
i = xfs_alloc_lookup_eq(bno_cur, fbno, flen);
ASSERT(i == 1);
}
/*
* If we're not using the whole space, insert an entry for the
* leftover space in the by-size btree, and update the by-block entry.
*/
if (rlen < flen) {
xfs_alloc_lookup_eq(cnt_cur, fbno + rlen, flen - rlen);
xfs_alloc_insert(cnt_cur);
xfs_alloc_update(bno_cur, fbno + rlen, flen - rlen);
}
/*
* Otherwise, just delete the entry from the by-block tree.
*/
else
xfs_alloc_delete(bno_cur);
*len = rlen;
xfs_alloc_rcheck(bno_cur);
xfs_alloc_kcheck(bno_cur);
xfs_btree_del_cursor(bno_cur);
xfs_alloc_rcheck(cnt_cur);
xfs_alloc_kcheck(cnt_cur);
xfs_btree_del_cursor(cnt_cur);
return fbno;
}
/*
* Free the extent starting at agno/bno for length.
*/
STATIC int /* return success/failure, will be void */
xfs_free_ag_extent(
xfs_trans_t *tp, /* transaction pointer */
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 */
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 */
mp = tp->t_mountp;
/*
* Allocate and initialize a cursor for the by-block btree.
*/
bno_cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO, 0);
/*
* Look for a neighboring block on the left (lower block numbers)
* that is contiguous with this space.
*/
if (haveleft = xfs_alloc_lookup_le(bno_cur, bno, len)) {
/*
* There is a block to our left.
*/
xfs_alloc_get_rec(bno_cur, <bno, <len);
/*
* It's not contiguous, though.
*/
if (ltbno + ltlen < bno)
haveleft = 0;
/*
* If this happens the request to free this space was
* invalid, it's (partly) already free.
*/
else if (ltbno + ltlen > bno) {
xfs_btree_del_cursor(bno_cur);
return 0;
/* WILL BE ASSERT XXX */
}
}
/*
* Look for a neighboring block on the right (higher block numbers)
* that is contiguous with this space.
*/
if (haveright = xfs_alloc_increment(bno_cur, 0)) {
/*
* There is a block to our right.
*/
xfs_alloc_get_rec(bno_cur, >bno, >len);
/*
* It's not contiguous, though.
*/
if (bno + len < gtbno)
haveright = 0;
/*
* If this happens the request to free this space was
* invalid, it's (partly) already free.
*/
else if (gtbno < bno + len) {
xfs_btree_del_cursor(bno_cur);
return 0;
/* WILL BE ASSERT XXX */
}
}
/*
* Now allocate and initialize a cursor for the by-size tree.
*/
cnt_cur = xfs_btree_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT, 0);
/*
* 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.
*/
i = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen);
ASSERT(i == 1);
xfs_alloc_delete(cnt_cur);
/*
* Delete the old by-size entry on the right.
*/
i = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen);
ASSERT(i == 1);
xfs_alloc_delete(cnt_cur);
/*
* Delete the old by-block entry for the right block.
*/
xfs_alloc_delete(bno_cur);
/*
* Move the by-block cursor back to the left neighbor.
*/
xfs_alloc_decrement(bno_cur, 0);
#ifdef DEBUG
/*
* Check that this is the right record: delete didn't
* mangle the cursor.
*/
{
xfs_agblock_t xxbno;
xfs_extlen_t xxlen;
xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen);
ASSERT(xxbno == ltbno);
ASSERT(xxlen == ltlen);
}
#endif
/*
* Update remaining by-block entry to the new, joined block.
*/
nbno = ltbno;
nlen = len + ltlen + gtlen;
xfs_alloc_update(bno_cur, nbno, nlen);
}
/*
* 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.
*/
i = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen);
ASSERT(i == 1);
xfs_alloc_delete(cnt_cur);
/*
* Back up the by-block cursor to the left neighbor, and
* update its length.
*/
xfs_alloc_decrement(bno_cur, 0);
nbno = ltbno;
nlen = len + ltlen;
xfs_alloc_update(bno_cur, nbno, nlen);
}
/*
* 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.
*/
i = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen);
ASSERT(i == 1);
xfs_alloc_delete(cnt_cur);
/*
* Update the starting block and length of the right
* neighbor in the by-block tree.
*/
nbno = bno;
nlen = len + gtlen;
xfs_alloc_update(bno_cur, nbno, nlen);
}
/*
* No contiguous neighbors.
* Insert the new freespace into the by-block tree.
*/
else {
nbno = bno;
nlen = len;
xfs_alloc_insert(bno_cur);
}
xfs_alloc_rcheck(bno_cur);
xfs_alloc_kcheck(bno_cur);
xfs_btree_del_cursor(bno_cur);
/*
* In all cases we need to insert the new freespace in the by-size tree.
*/
xfs_alloc_lookup_eq(cnt_cur, nbno, nlen);
xfs_alloc_insert(cnt_cur);
xfs_alloc_rcheck(cnt_cur);
xfs_alloc_kcheck(cnt_cur);
xfs_btree_del_cursor(cnt_cur);
/*
* Update the freespace totals in the ag and superblock.
*/
{
xfs_agf_t *agf;
agf = XFS_BUF_TO_AGF(agbp);
agf->agf_freeblks += len;
xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
if (!isfl)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (int)len);
}
return 1;
}
/*
* Visible (exported) allocation/free functions.
* Some of these are used just by xfs_alloc_btree.c and this file.
*/
/*
* Return the number of free blocks left in the allocation group.
* Return 0 if flags has XFS_ALLOC_FLAG_TRYLOCK and the lock fails.
*/
xfs_extlen_t /* number of remaining free blocks */
xfs_alloc_ag_freeblks(
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_FLAG_... */
{
buf_t *agbp; /* buffer for a.g. freelist structure */
xfs_agf_t *agf; /* a.g. freelist structure */
xfs_extlen_t freeblks;/* return value */
agbp = xfs_alloc_read_agf(mp, tp, agno, flags);
if (!agbp)
return 0;
agf = XFS_BUF_TO_AGF(agbp);
freeblks = agf->agf_freeblks;
xfs_trans_brelse(tp, agbp);
return freeblks;
}
/*
* 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;
}
/*
* Allocate an extent (fixed-size).
* Return the extent's starting block, NULLFSBLOCK on failure.
*/
xfs_fsblock_t /* extent's starting block */
xfs_alloc_extent(
xfs_trans_t *tp, /* transaction pointer */
xfs_fsblock_t bno, /* requested starting block */
xfs_extlen_t len, /* requested length */
xfs_alloctype_t type, /* allocation type, see above defn */
xfs_extlen_t total, /* total blocks needed in transaction */
int wasdel) /* extent was previously del-alloced */
{
xfs_extlen_t rlen; /* returned length from xfs_alloc_vextent */
xfs_fsblock_t rval; /* return value */
rval = xfs_alloc_vextent(tp, bno, len, len, &rlen, type, total, wasdel,
0, 1);
if (rval != NULLFSBLOCK)
ASSERT(rlen == len);
return rval;
}
/*
* Decide whether to use this allocation group for this allocation.
* If so, fix up the btree freelist's size.
* This is external so mkfs can call it, too.
*/
buf_t * /* buffer for the a.g. freelist header */
xfs_alloc_fix_freelist(
xfs_trans_t *tp, /* transaction pointer */
xfs_agnumber_t agno, /* allocation group number */
xfs_extlen_t minlen, /* minimum extent length, else reject */
xfs_extlen_t total, /* total free blocks, else reject */
int flags) /* XFS_ALLOC_FLAG_... */
{
xfs_agblock_t agbno;
buf_t *agbp;
xfs_agf_t *agf;
xfs_agblock_t bno;
buf_t *bp;
xfs_mount_t *mp;
xfs_extlen_t need;
mp = tp->t_mountp;
/*
* Get the a.g. freespace buffer.
* Can fail if we're not blocking on locks, and it's held.
*/
agbp = xfs_alloc_read_agf(mp, tp, agno, flags);
if (!agbp)
return NULL;
/*
* Figure out how many blocks we should have in the freelist.
*/
agf = XFS_BUF_TO_AGF(agbp);
need = XFS_MIN_FREELIST(agf, mp);
/*
* Adjust total blocks to be allocated, if it's given.
*/
if (total && agf->agf_freecount < need)
total += need - agf->agf_freecount;
/*
* If there isn't enough total or single-extent, reject it.
*/
if (minlen > agf->agf_longest || total > agf->agf_freeblks) {
xfs_trans_brelse(tp, agbp);
return NULL;
}
/*
* Make the freelist shorter if it's too long.
*/
while (agf->agf_freecount > need) {
bno = xfs_alloc_get_freelist(tp, agbp, &bp);
xfs_free_ag_extent(tp, agbp, agno, bno, 1, 1);
}
/*
* Make the freelist longer if it's too short.
*/
while (agf->agf_freecount < need) {
xfs_extlen_t i;
i = need - agf->agf_freecount;
/*
* Allocate as many blocks as possible at once.
*/
agbno = xfs_alloc_ag_vextent(tp, agbp, agno, 0, 1, i, &i,
XFS_ALLOCTYPE_THIS_AG, 0, 0, 1, 1);
/*
* Stop if we run out. Won't happen if callers are obeying
* the restrictions correctly.
*/
if (agbno == NULLAGBLOCK)
break;
/*
* Put each allocated block on the list.
*/
for (bno = agbno + i - 1; bno >= agbno; bno--) {
bp = xfs_btree_get_bufs(mp, tp, agno, bno, 0);
xfs_alloc_put_freelist(tp, agbp, bp);
}
}
return agbp;
}
/*
* Get a block from the freelist.
* Returns with the buffer for the block gotten.
*/
xfs_agblock_t /* block address retrieved from freelist */
xfs_alloc_get_freelist(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer containing the agf structure */
buf_t **bufp) /* out: buffer pointer for the free block */
{
xfs_agf_t *agf; /* a.g. freespace structure */
xfs_alloc_block_t *block; /* block's data */
xfs_agblock_t bno; /* block number returned */
buf_t *bp; /* buffer for the block */
xfs_mount_t *mp; /* mount point for filesystem */
mp = tp->t_mountp;
agf = XFS_BUF_TO_AGF(agbp);
bno = agf->agf_freelist;
/*
* Freelist is empty, give up.
*/
if (bno == NULLAGBLOCK)
return NULLAGBLOCK;
bp = xfs_btree_read_bufs(mp, tp, agf->agf_seqno, bno, 0);
block = XFS_BUF_TO_ALLOC_BLOCK(bp);
agf->agf_freecount--;
/*
* The link to the next block is stored as the first word of the block.
*/
agf->agf_freelist = *(xfs_agblock_t *)block;
xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREELIST | XFS_AGF_FREECOUNT);
if (bufp)
*bufp = bp;
else
xfs_trans_brelse(tp, bp);
kmem_check();
return bno;
}
/*
* Log the given fields from the agf structure.
*/
void
xfs_alloc_log_agf(
xfs_trans_t *tp, /* transaction pointer */
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 int 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_freelist),
offsetof(xfs_agf_t, agf_freecount),
offsetof(xfs_agf_t, agf_freeblks),
offsetof(xfs_agf_t, agf_longest),
sizeof(xfs_agf_t)
};
xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last);
xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
kmem_check();
}
/*
* Find the next freelist block number. For printing routines.
*/
xfs_agblock_t /* a.g.-relative block number for btree list */
xfs_alloc_next_free(
xfs_mount_t *mp, /* file system mount structure */
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
xfs_agblock_t bno) /* current freelist block number */
{
xfs_agf_t *agf; /* a.g. freespace structure */
buf_t *bp; /* buffer for next freelist block */
agf = XFS_BUF_TO_AGF(agbp);
bp = xfs_btree_read_bufs(mp, tp, agf->agf_seqno, bno, 0);
bno = *(xfs_agblock_t *)bp->b_un.b_addr;
xfs_trans_brelse(tp, bp);
return bno;
}
/*
* Put the buffer on the freelist for the allocation group.
*/
void
xfs_alloc_put_freelist(
xfs_trans_t *tp, /* transaction pointer */
buf_t *agbp, /* buffer for a.g. freelist header */
buf_t *bp) /* buffer for the block being freed */
{
xfs_agf_t *agf; /* a.g. freespace structure */
xfs_alloc_block_t *block; /* data of "bp" */
xfs_agblock_t bno; /* block number of bp */
xfs_mount_t *mp; /* mount point of filesystem */
mp = tp->t_mountp;
agf = XFS_BUF_TO_AGF(agbp);
block = XFS_BUF_TO_ALLOC_BLOCK(bp);
/*
* Point the new block to the old head of the list.
*/
*(xfs_agblock_t *)block = agf->agf_freelist;
xfs_trans_log_buf(tp, bp, 0, (int)sizeof(xfs_agblock_t) - 1);
bno = XFS_DADDR_TO_AGBNO(mp, bp->b_blkno);
agf->agf_freelist = bno;
agf->agf_freecount++;
xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREELIST | XFS_AGF_FREECOUNT);
kmem_check();
}
/*
* 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.
*/
xfs_fsblock_t /* extent's starting block, or NULLFSBLOCK */
xfs_alloc_vextent(
xfs_trans_t *tp, /* transaction pointer */
xfs_fsblock_t bno, /* requested starting block */
xfs_extlen_t minlen, /* minimum requested length */
xfs_extlen_t maxlen, /* maximum requested length */
xfs_extlen_t *len, /* output: actual allocated length */
xfs_alloctype_t type, /* allocation type, see above definition */
xfs_extlen_t total, /* total blocks needed in transaction */
int wasdel, /* extent was previously delayed-allocated */
xfs_extlen_t mod, /* length should be k * prod + mod unless */
xfs_extlen_t prod) /* there's nothing as big as mod */
{
xfs_agblock_t agbno; /* start of allocated extent */
buf_t *agbp; /* a.g. freespace header buffer */
xfs_agnumber_t agno; /* allocation group number selected */
xfs_agblock_t agsize; /* allocation group size */
int flags; /* locking flags */
xfs_mount_t *mp; /* mount point for filesystem */
xfs_alloctype_t ntype; /* actual type used for allocating */
xfs_sb_t *sbp; /* superblock structure */
xfs_agnumber_t tagno; /* allocation group number being tried */
ntype = type;
mp = tp->t_mountp;
sbp = &mp->m_sb;
agsize = sbp->sb_agblocks;
/*
* These should really be asserts, left this way for now just
* for the benefit of xfs_test.
*/
if (XFS_FSB_TO_AGNO(mp, bno) >= sbp->sb_agcount ||
XFS_FSB_TO_AGBNO(mp, bno) >= sbp->sb_agblocks || minlen > maxlen ||
minlen > agsize || len == 0 || mod >= prod)
return NULLFSBLOCK;
/*
* 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).
*/
if (maxlen > agsize)
maxlen = agsize;
agbno = NULLAGBLOCK;
ntype = XFS_ALLOCTYPE_THIS_AG;
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.
*/
agno = XFS_FSB_TO_AGNO(mp, bno);
agbp = xfs_alloc_fix_freelist(tp, agno, minlen, total, 0);
if (!agbp)
break;
agbno = XFS_FSB_TO_AGBNO(mp, bno);
agbno = xfs_alloc_ag_vextent(tp, agbp, agno, agbno, minlen,
maxlen, len, type, wasdel, mod, prod, 0);
break;
case XFS_ALLOCTYPE_START_BNO:
/*
* Try near allocation first, then anywhere-in-ag after
* the first a.g. fails.
*/
agbno = XFS_FSB_TO_AGBNO(mp, bno);
ntype = 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.
*/
tagno = agno = mp->m_agrotor;
flags = XFS_ALLOC_FLAG_TRYLOCK;
} else if (type == XFS_ALLOCTYPE_FIRST_AG) {
/*
* Start with allocation group given by bno.
*/
tagno = XFS_FSB_TO_AGNO(mp, bno);
agno = 0;
flags = 0;
} else {
/*
* Start with the given allocation group.
*/
tagno = agno = XFS_FSB_TO_AGNO(mp, bno);
flags = XFS_ALLOC_FLAG_TRYLOCK;
}
/*
* Loop over allocation groups twice; first time with
* trylock set, second time without.
*/
for (;;) {
agbp = xfs_alloc_fix_freelist(tp, tagno, minlen,
total, flags);
/*
* If we get a buffer back then the allocation will fly.
*/
if (agbp) {
agbno = xfs_alloc_ag_vextent(tp, agbp, tagno,
agbno, minlen, maxlen, len, ntype,
wasdel, mod, prod, 0);
break;
}
/*
* Didn't work, figure out the next iteration.
*/
if (tagno == agno && type == XFS_ALLOCTYPE_START_BNO)
ntype = XFS_ALLOCTYPE_THIS_AG;
if (++tagno == sbp->sb_agcount)
tagno = 0;
/*
* Reached the starting a.g., must either be done
* or switch to non-trylock mode.
*/
if (tagno == agno) {
if (!flags)
break;
flags = 0;
if (type == XFS_ALLOCTYPE_START_BNO)
ntype = XFS_ALLOCTYPE_NEAR_BNO;
}
}
agno = tagno;
mp->m_agrotor = (agno + 1) % sbp->sb_agcount;
break;
default:
ASSERT(0);
/* NOTREACHED */
}
if (agbno == NULLAGBLOCK)
return NULLFSBLOCK;
else
return XFS_AGB_TO_FSB(mp, agno, agbno);
}
/*
* Free an extent.
* Just break up the extent address and hand off to xfs_free_ag_extent
* after fixing up the freelist.
*/
int /* success/failure; will become void */
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_agblock_t agbno; /* bno relative to allocation group */
buf_t *agbp; /* buffer for a.g. freespace header */
xfs_agnumber_t agno; /* allocation group number */
xfs_mount_t *mp; /* mount point for filesystem */
xfs_sb_t *sbp; /* superblock for filesystem */
mp = tp->t_mountp;
sbp = &mp->m_sb;
ASSERT(len != 0);
agno = XFS_FSB_TO_AGNO(mp, bno);
ASSERT(agno < sbp->sb_agcount);
agbno = XFS_FSB_TO_AGBNO(mp, bno);
ASSERT(agbno < sbp->sb_agblocks);
agbp = xfs_alloc_fix_freelist(tp, agno, 0, 0, 0);
ASSERT(agbp != NULL);
return xfs_free_ag_extent(tp, agbp, agno, agbno, len, 0);
}
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