Google Git
Sign in
gem5 / arm / linux / e8f0f8aa4eb356bd729f15be8827db2558ea1ae6 / . / fs / xfs / libxfs / xfs_alloc.c
blob: 3dd8f1d5449877ed45aa0fb391c1e9048c5c1893 [file] [log] [blame]
/*
* 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_format.h"
#include "xfs_log_format.h"
#include "xfs_shared.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_rmap.h"
#include "xfs_alloc_btree.h"
#include "xfs_alloc.h"
#include "xfs_extent_busy.h"
#include "xfs_error.h"
#include "xfs_cksum.h"
#include "xfs_trace.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_log.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 *);
xfs_extlen_t
xfs_prealloc_blocks(
struct xfs_mount *mp)
{
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
return XFS_RMAP_BLOCK(mp) + 1;
if (xfs_sb_version_hasfinobt(&mp->m_sb))
return XFS_FIBT_BLOCK(mp) + 1;
return XFS_IBT_BLOCK(mp) + 1;
}
/*
* In order to avoid ENOSPC-related deadlock caused by out-of-order locking of
* AGF buffer (PV 947395), we place constraints on the relationship among
* actual allocations for data blocks, freelist blocks, and potential file data
* bmap btree blocks. However, these restrictions may result in no actual space
* allocated for a delayed extent, for example, a data block in a certain AG is
* allocated but there is no additional block for the additional bmap btree
* block due to a split of the bmap btree of the file. The result of this may
* lead to an infinite loop when the file gets flushed to disk and all delayed
* extents need to be actually allocated. To get around this, we explicitly set
* aside a few blocks which will not be reserved in delayed allocation.
*
* When rmap is disabled, we need to reserve 4 fsbs _per AG_ for the freelist
* and 4 more to handle a potential split of the file's bmap btree.
*
* When rmap is enabled, we must also be able to handle two rmap btree inserts
* to record both the file data extent and a new bmbt block. The bmbt block
* might not be in the same AG as the file data extent. In the worst case
* the bmap btree splits multiple levels and all the new blocks come from
* different AGs, so set aside enough to handle rmap btree splits in all AGs.
*/
unsigned int
xfs_alloc_set_aside(
struct xfs_mount *mp)
{
unsigned int blocks;
blocks = 4 + (mp->m_sb.sb_agcount * XFS_ALLOC_AGFL_RESERVE);
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
blocks += mp->m_sb.sb_agcount * mp->m_rmap_maxlevels;
return blocks;
}
/*
* When deciding how much space to allocate out of an AG, we limit the
* allocation maximum size to the size the AG. However, we cannot use all the
* blocks in the AG - some are permanently used by metadata. These
* blocks are generally:
* - the AG superblock, AGF, AGI and AGFL
* - the AGF (bno and cnt) and AGI btree root blocks, and optionally
* the AGI free inode and rmap btree root blocks.
* - blocks on the AGFL according to xfs_alloc_set_aside() limits
* - the rmapbt root block
*
* The AG headers are sector sized, so the amount of space they take up is
* dependent on filesystem geometry. The others are all single blocks.
*/
unsigned int
xfs_alloc_ag_max_usable(
struct xfs_mount *mp)
{
unsigned int blocks;
blocks = XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)); /* ag headers */
blocks += XFS_ALLOC_AGFL_RESERVE;
blocks += 3; /* AGF, AGI btree root blocks */
if (xfs_sb_version_hasfinobt(&mp->m_sb))
blocks++; /* finobt root block */
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
blocks++; /* rmap root block */
return mp->m_sb.sb_agblocks - blocks;
}
/*
* 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.
*/
static 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;
xfs_extlen_t diff;
/* Trim busy sections out of found extent */
xfs_extent_busy_trim(args, foundbno, foundlen, &bno, &len);
/*
* If we have a largish extent that happens to start before min_agbno,
* see if we can shift it into range...
*/
if (bno < args->min_agbno && bno + len > args->min_agbno) {
diff = args->min_agbno - bno;
if (len > diff) {
bno += diff;
len -= diff;
}
}
if (args->alignment > 1 && len >= args->minlen) {
xfs_agblock_t aligned_bno = roundup(bno, args->alignment);
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 */
char userdata, /* are we allocating data? */
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;
/*
* We want to allocate from the start of a free extent if it is past
* the desired block or if we are allocating user data and the free
* extent is before desired block. The second case is there to allow
* for contiguous allocation from the remaining free space if the file
* grows in the short term.
*/
if (freebno >= wantbno || (userdata && freeend < wantend)) {
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)
rlen = rlen - (k - args->mod);
else
rlen = rlen - args->prod + (args->mod - k);
/* casts to (int) catch length underflows */
if ((int)rlen < (int)args->minlen)
return;
ASSERT(rlen >= args->minlen && rlen <= args->maxlen);
ASSERT(rlen % args->prod == args->mod);
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 */
/* casts to (int) catch length underflows */
if ((int)args->len >= (int)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 */
struct xfs_mount *mp;
mp = cnt_cur->bc_mp;
/*
* 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(mp,
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(mp, 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(mp,
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(mp, 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(mp,
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(mp, 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(mp, i == 0);
if ((error = xfs_btree_insert(cnt_cur, &i)))
return error;
XFS_WANT_CORRUPTED_RETURN(mp, i == 1);
}
if (nfbno2 != NULLAGBLOCK) {
if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
return error;
XFS_WANT_CORRUPTED_RETURN(mp, i == 0);
if ((error = xfs_btree_insert(cnt_cur, &i)))
return error;
XFS_WANT_CORRUPTED_RETURN(mp, 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(mp, 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(mp, i == 0);
if ((error = xfs_btree_insert(bno_cur, &i)))
return error;
XFS_WANT_CORRUPTED_RETURN(mp, i == 1);
}
return 0;
}
static bool
xfs_agfl_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
int i;
if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid))
return false;
if (be32_to_cpu(agfl->agfl_magicnum) != XFS_AGFL_MAGIC)
return false;
/*
* during growfs operations, the perag is not fully initialised,
* so we can't use it for any useful checking. growfs ensures we can't
* use it by using uncached buffers that don't have the perag attached
* so we can detect and avoid this problem.
*/
if (bp->b_pag && be32_to_cpu(agfl->agfl_seqno) != bp->b_pag->pag_agno)
return false;
for (i = 0; i < XFS_AGFL_SIZE(mp); i++) {
if (be32_to_cpu(agfl->agfl_bno[i]) != NULLAGBLOCK &&
be32_to_cpu(agfl->agfl_bno[i]) >= mp->m_sb.sb_agblocks)
return false;
}
return xfs_log_check_lsn(mp,
be64_to_cpu(XFS_BUF_TO_AGFL(bp)->agfl_lsn));
}
static void
xfs_agfl_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
/*
* There is no verification of non-crc AGFLs because mkfs does not
* initialise the AGFL to zero or NULL. Hence the only valid part of the
* AGFL is what the AGF says is active. We can't get to the AGF, so we
* can't verify just those entries are valid.
*/
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
if (!xfs_buf_verify_cksum(bp, XFS_AGFL_CRC_OFF))
xfs_buf_ioerror(bp, -EFSBADCRC);
else if (!xfs_agfl_verify(bp))
xfs_buf_ioerror(bp, -EFSCORRUPTED);
if (bp->b_error)
xfs_verifier_error(bp);
}
static void
xfs_agfl_write_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_buf_log_item *bip = bp->b_fspriv;
/* no verification of non-crc AGFLs */
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
if (!xfs_agfl_verify(bp)) {
xfs_buf_ioerror(bp, -EFSCORRUPTED);
xfs_verifier_error(bp);
return;
}
if (bip)
XFS_BUF_TO_AGFL(bp)->agfl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
xfs_buf_update_cksum(bp, XFS_AGFL_CRC_OFF);
}
const struct xfs_buf_ops xfs_agfl_buf_ops = {
.name = "xfs_agfl",
.verify_read = xfs_agfl_read_verify,
.verify_write = xfs_agfl_write_verify,
};
/*
* 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, &xfs_agfl_buf_ops);
if (error)
return error;
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 not file data, insert new block into the reverse map btree */
if (args->oinfo.oi_owner != XFS_RMAP_OWN_UNKNOWN) {
error = xfs_rmap_alloc(args->tp, args->agbp, args->agno,
args->agbno, args->len, &args->oinfo);
if (error)
return error;
}
if (!args->wasfromfl) {
error = xfs_alloc_update_counters(args->tp, args->pag,
args->agbp,
-((long)(args->len)));
if (error)
return error;
ASSERT(!xfs_extent_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(args->mp, xs_allocx);
XFS_STATS_ADD(args->mp, 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(args->mp, i == 1, error0);
ASSERT(fbno <= args->agbno);
/*
* Check for overlapping busy extents.
*/
xfs_extent_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(args->mp, 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->max_agbno)
goto out_use_good;
if (*sbnoa >= args->agbno + gdiff)
goto out_use_good;
} else {
if (*sbnoa < args->min_agbno)
goto out_use_good;
if (*sbnoa <= args->agbno - gdiff)
goto out_use_good;
}
/*
* 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,
args->userdata, *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;
#ifdef DEBUG
/*
* Randomly don't execute the first algorithm.
*/
int dofirst; /* set to do first algorithm */
dofirst = prandom_u32() & 1;
#endif
/* handle unitialized agbno range so caller doesn't have to */
if (!args->min_agbno && !args->max_agbno)
args->max_agbno = args->mp->m_sb.sb_agblocks - 1;
ASSERT(args->min_agbno <= args->max_agbno);
/* clamp agbno to the range if it's outside */
if (args->agbno < args->min_agbno)
args->agbno = args->min_agbno;
if (args->agbno > args->max_agbno)
args->agbno = args->max_agbno;
restart:
bno_cur_lt = NULL;
bno_cur_gt = NULL;
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, &ltbno,
&ltlen, &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;
#ifdef DEBUG
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, &ltbno,
&ltlen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(args->mp, 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, &ltbno, &ltlen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
xfs_alloc_compute_aligned(args, ltbno, ltlen,
&ltbnoa, &ltlena);
if (ltlena < args->minlen)
continue;
if (ltbnoa < args->min_agbno || ltbnoa > args->max_agbno)
continue;
args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
xfs_alloc_fix_len(args);
ASSERT(args->len >= args->minlen);
if (args->len < blen)
continue;
ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
args->alignment, args->userdata, ltbnoa,
ltlena, &ltnew);
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, &ltbno, &ltlen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(args->mp, 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, &ltbno, &ltlen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
xfs_alloc_compute_aligned(args, ltbno, ltlen,
&ltbnoa, &ltlena);
if (ltlena >= args->minlen && ltbnoa >= args->min_agbno)
break;
if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i)))
goto error0;
if (!i || ltbnoa < args->min_agbno) {
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, &gtbno, &gtlen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
xfs_alloc_compute_aligned(args, gtbno, gtlen,
&gtbnoa, &gtlena);
if (gtlena >= args->minlen && gtbnoa <= args->max_agbno)
break;
if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
goto error0;
if (!i || gtbnoa > args->max_agbno) {
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, args->userdata, ltbnoa,
ltlena, &ltnew);
error = xfs_alloc_find_best_extent(args,
&bno_cur_lt, &bno_cur_gt,
ltdiff, &gtbno, &gtlen,
&gtbnoa, &gtlena,
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, args->userdata, gtbnoa,
gtlena, &gtnew);
error = xfs_alloc_find_best_extent(args,
&bno_cur_gt, &bno_cur_lt,
gtdiff, &ltbno, &ltlen,
&ltbnoa, &ltlena,
1 /* search left */);
}
if (error)
goto error0;
}
/*
* If we couldn't get anything, give up.
*/
if (bno_cur_lt == NULL && bno_cur_gt == NULL) {
xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
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,
args->userdata, ltbnoa, ltlena, &ltnew);
ASSERT(ltnew >= ltbno);
ASSERT(ltnew + rlen <= ltbnoa + ltlena);
ASSERT(ltnew + rlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
ASSERT(ltnew >= args->min_agbno && ltnew <= args->max_agbno);
args->agbno = ltnew;
if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, ltlen,
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(args->mp, 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(args->mp, 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(args->mp, 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(args->mp, 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(args->mp, 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(args->mp, 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->mp,
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 */
{
struct xfs_owner_info oinfo;
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(args->mp, 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_extent_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->mp,
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);
/*
* If we're feeding an AGFL block to something that
* doesn't live in the free space, we need to clear
* out the OWN_AG rmap.
*/
xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_AG);
error = xfs_rmap_free(args->tp, args->agbp, args->agno,
fbno, 1, &oinfo);
if (error)
goto error0;
*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
xfs_free_ag_extent(
xfs_trans_t *tp,
xfs_buf_t *agbp,
xfs_agnumber_t agno,
xfs_agblock_t bno,
xfs_extlen_t len,
struct xfs_owner_info *oinfo,
int isfl)
{
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 */
bno_cur = cnt_cur = NULL;
mp = tp->t_mountp;
if (oinfo->oi_owner != XFS_RMAP_OWN_UNKNOWN) {
error = xfs_rmap_free(tp, agbp, agno, bno, len, oinfo);
if (error)
goto error0;
}
/*
* Allocate and initialize a cursor for the by-block btree.
*/
bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO);
/*
* 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, &ltbno, &ltlen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(mp, 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(mp,
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, &gtbno, &gtlen, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(mp, 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(mp, 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(mp, i == 1, error0);
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(mp, 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(mp, i == 1, error0);
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(mp, 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(mp, 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(mp, 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(mp,
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(mp, i == 1, error0);
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(mp, 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(mp, 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(mp, i == 1, error0);
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(mp, 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(mp, 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(mp, i == 0, error0);
if ((error = xfs_btree_insert(cnt_cur, &i)))
goto error0;
XFS_WANT_CORRUPTED_GOTO(mp, 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(mp, xs_freex);
XFS_STATS_ADD(mp, 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 */
{
mp->m_ag_maxlevels = xfs_btree_compute_maxlevels(mp, mp->m_alloc_mnr,
(mp->m_sb.sb_agblocks + 1) / 2);
}
/*
* 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)
{
xfs_extlen_t delta = 0;
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;
}
unsigned int
xfs_alloc_min_freelist(
struct xfs_mount *mp,
struct xfs_perag *pag)
{
unsigned int min_free;
/* space needed by-bno freespace btree */
min_free = min_t(unsigned int, pag->pagf_levels[XFS_BTNUM_BNOi] + 1,
mp->m_ag_maxlevels);
/* space needed by-size freespace btree */
min_free += min_t(unsigned int, pag->pagf_levels[XFS_BTNUM_CNTi] + 1,
mp->m_ag_maxlevels);
/* space needed reverse mapping used space btree */
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
min_free += min_t(unsigned int,
pag->pagf_levels[XFS_BTNUM_RMAPi] + 1,
mp->m_rmap_maxlevels);
return min_free;
}
/*
* Check if the operation we are fixing up the freelist for should go ahead or
* not. If we are freeing blocks, we always allow it, otherwise the allocation
* is dependent on whether the size and shape of free space available will
* permit the requested allocation to take place.
*/
static bool
xfs_alloc_space_available(
struct xfs_alloc_arg *args,
xfs_extlen_t min_free,
int flags)
{
struct xfs_perag *pag = args->pag;
xfs_extlen_t longest;
int available;
if (flags & XFS_ALLOC_FLAG_FREEING)
return true;
/* do we have enough contiguous free space for the allocation? */
longest = xfs_alloc_longest_free_extent(args->mp, pag, min_free);
if ((args->minlen + args->alignment + args->minalignslop - 1) > longest)
return false;
/* do have enough free space remaining for the allocation? */
available = (int)(pag->pagf_freeblks + pag->pagf_flcount -
min_free - args->total);
if (available < (int)args->minleft)
return false;
return true;
}
/*
* Decide whether to use this allocation group for this allocation.
* If so, fix up the btree freelist's size.
*/
int /* error */
xfs_alloc_fix_freelist(
struct xfs_alloc_arg *args, /* allocation argument structure */
int flags) /* XFS_ALLOC_FLAG_... */
{
struct xfs_mount *mp = args->mp;
struct xfs_perag *pag = args->pag;
struct xfs_trans *tp = args->tp;
struct xfs_buf *agbp = NULL;
struct xfs_buf *agflbp = NULL;
struct xfs_alloc_arg targs; /* local allocation arguments */
xfs_agblock_t bno; /* freelist block */
xfs_extlen_t need; /* total blocks needed in freelist */
int error = 0;
if (!pag->pagf_init) {
error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
if (error)
goto out_no_agbp;
if (!pag->pagf_init) {
ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
goto out_agbp_relse;
}
}
/*
* 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));
goto out_agbp_relse;
}
need = xfs_alloc_min_freelist(mp, pag);
if (!xfs_alloc_space_available(args, need, flags))
goto out_agbp_relse;
/*
* Get the a.g. freespace buffer.
* Can fail if we're not blocking on locks, and it's held.
*/
if (!agbp) {
error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
if (error)
goto out_no_agbp;
if (!agbp) {
ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
goto out_no_agbp;
}
}
/* If there isn't enough total space or single-extent, reject it. */
need = xfs_alloc_min_freelist(mp, pag);
if (!xfs_alloc_space_available(args, need, flags))
goto out_agbp_relse;
/*
* Make the freelist shorter if it's too long.
*
* Note that from this point onwards, we will always release the agf and
* agfl buffers on error. This handles the case where we error out and
* the buffers are clean or may not have been joined to the transaction
* and hence need to be released manually. If they have been joined to
* the transaction, then xfs_trans_brelse() will handle them
* appropriately based on the recursion count and dirty state of the
* buffer.
*
* XXX (dgc): When we have lots of free space, does this buy us
* anything other than extra overhead when we need to put more blocks
* back on the free list? Maybe we should only do this when space is
* getting low or the AGFL is more than half full?
*
* The NOSHRINK flag prevents the AGFL from being shrunk if it's too
* big; the NORMAP flag prevents AGFL expand/shrink operations from
* updating the rmapbt. Both flags are used in xfs_repair while we're
* rebuilding the rmapbt, and neither are used by the kernel. They're
* both required to ensure that rmaps are correctly recorded for the
* regenerated AGFL, bnobt, and cntbt. See repair/phase5.c and
* repair/rmap.c in xfsprogs for details.
*/
memset(&targs, 0, sizeof(targs));
if (flags & XFS_ALLOC_FLAG_NORMAP)
xfs_rmap_skip_owner_update(&targs.oinfo);
else
xfs_rmap_ag_owner(&targs.oinfo, XFS_RMAP_OWN_AG);
while (!(flags & XFS_ALLOC_FLAG_NOSHRINK) && pag->pagf_flcount > need) {
struct xfs_buf *bp;
error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
if (error)
goto out_agbp_relse;
error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1,
&targs.oinfo, 1);
if (error)
goto out_agbp_relse;
bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
xfs_trans_binval(tp, bp);
}
targs.tp = tp;
targs.mp = mp;
targs.agbp = agbp;
targs.agno = args->agno;
targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;
targs.type = XFS_ALLOCTYPE_THIS_AG;
targs.pag = pag;
error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);
if (error)
goto out_agbp_relse;
/* Make the freelist longer if it's too short. */
while (pag->pagf_flcount < need) {
targs.agbno = 0;
targs.maxlen = need - pag->pagf_flcount;
/* Allocate as many blocks as possible at once. */
error = xfs_alloc_ag_vextent(&targs);
if (error)
goto out_agflbp_relse;
/*
* 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;
goto out_agflbp_relse;
}
/*
* 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)
goto out_agflbp_relse;
}
}
xfs_trans_brelse(tp, agflbp);
args->agbp = agbp;
return 0;
out_agflbp_relse:
xfs_trans_brelse(tp, agflbp);
out_agbp_relse:
if (agbp)
xfs_trans_brelse(tp, agbp);
out_no_agbp:
args->agbp = NULL;
return error;
}
/*
* 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_buf_t *agflbp;/* buffer for a.g. freelist structure */
xfs_agblock_t bno; /* block number returned */
__be32 *agfl_bno;
int error;
int logflags;
xfs_mount_t *mp = tp->t_mountp;
xfs_perag_t *pag; /* per allocation group data */
/*
* Freelist is empty, give up.
*/
agf = XFS_BUF_TO_AGF(agbp);
if (!agf->agf_flcount) {
*bnop = NULLAGBLOCK;
return 0;
}
/*
* Read the array of free blocks.
*/
error = xfs_alloc_read_agfl(mp, tp, be32_to_cpu(agf->agf_seqno),
&agflbp);
if (error)
return error;
/*
* Get the block number and update the data structures.
*/
agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
bno = be32_to_cpu(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),
offsetof(xfs_agf_t, agf_uuid),
offsetof(xfs_agf_t, agf_rmap_blocks),
sizeof(xfs_agf_t)
};
trace_xfs_agf(tp->t_mountp, XFS_BUF_TO_AGF(bp), fields, _RET_IP_);
xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGF_BUF);
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 */
__be32 *blockp;/* pointer to array entry */
int error;
int logflags;
xfs_mount_t *mp; /* mount structure */
xfs_perag_t *pag; /* per allocation group data */
__be32 *agfl_bno;
int startoff;
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;
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));
agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
*blockp = cpu_to_be32(bno);
startoff = (char *)blockp - (char *)agflbp->b_addr;
xfs_alloc_log_agf(tp, agbp, logflags);
xfs_trans_buf_set_type(tp, agflbp, XFS_BLFT_AGFL_BUF);
xfs_trans_log_buf(tp, agflbp, startoff,
startoff + sizeof(xfs_agblock_t) - 1);
return 0;
}
static bool
xfs_agf_verify(
struct xfs_mount *mp,
struct xfs_buf *bp)
{
struct xfs_agf *agf = XFS_BUF_TO_AGF(bp);
if (xfs_sb_version_hascrc(&mp->m_sb)) {
if (!uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid))
return false;
if (!xfs_log_check_lsn(mp,
be64_to_cpu(XFS_BUF_TO_AGF(bp)->agf_lsn)))
return false;
}
if (!(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)))
return false;
if (be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) > XFS_BTREE_MAXLEVELS ||
be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) > XFS_BTREE_MAXLEVELS)
return false;
if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS)
return false;
/*
* during growfs operations, the perag is not fully initialised,
* so we can't use it for any useful checking. growfs ensures we can't
* use it by using uncached buffers that don't have the perag attached
* so we can detect and avoid this problem.
*/
if (bp->b_pag && be32_to_cpu(agf->agf_seqno) != bp->b_pag->pag_agno)
return false;
if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
be32_to_cpu(agf->agf_btreeblks) > be32_to_cpu(agf->agf_length))
return false;
return true;;
}
static void
xfs_agf_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
if (xfs_sb_version_hascrc(&mp->m_sb) &&
!xfs_buf_verify_cksum(bp, XFS_AGF_CRC_OFF))
xfs_buf_ioerror(bp, -EFSBADCRC);
else if (XFS_TEST_ERROR(!xfs_agf_verify(mp, bp), mp,
XFS_ERRTAG_ALLOC_READ_AGF,
XFS_RANDOM_ALLOC_READ_AGF))
xfs_buf_ioerror(bp, -EFSCORRUPTED);
if (bp->b_error)
xfs_verifier_error(bp);
}
static void
xfs_agf_write_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_buf_log_item *bip = bp->b_fspriv;
if (!xfs_agf_verify(mp, bp)) {
xfs_buf_ioerror(bp, -EFSCORRUPTED);
xfs_verifier_error(bp);
return;
}
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
if (bip)
XFS_BUF_TO_AGF(bp)->agf_lsn = cpu_to_be64(bip->bli_item.li_lsn);
xfs_buf_update_cksum(bp, XFS_AGF_CRC_OFF);
}
const struct xfs_buf_ops xfs_agf_buf_ops = {
.name = "xfs_agf",
.verify_read = xfs_agf_read_verify,
.verify_write = xfs_agf_write_verify,
};
/*
* 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 */
{
int error;
trace_xfs_read_agf(mp, agno);
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, &xfs_agf_buf_ops);
if (error)
return error;
if (!*bpp)
return 0;
ASSERT(!(*bpp)->b_error);
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;
trace_xfs_alloc_read_agf(mp, agno);
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]);
pag->pagf_levels[XFS_BTNUM_RMAPi] =
be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
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
/* Zero the extent if we were asked to do so */
if (args->userdata & XFS_ALLOC_USERDATA_ZERO) {
error = xfs_zero_extent(args->ip, args->fsbno, args->len);
if (error)
goto error0;
}
}
xfs_perag_put(args->pag);
return 0;
error0:
xfs_perag_put(args->pag);
return error;
}
/* Ensure that the freelist is at full capacity. */
int
xfs_free_extent_fix_freelist(
struct xfs_trans *tp,
xfs_agnumber_t agno,
struct xfs_buf **agbp)
{
struct xfs_alloc_arg args;
int error;
memset(&args, 0, sizeof(struct xfs_alloc_arg));
args.tp = tp;
args.mp = tp->t_mountp;
args.agno = agno;
/*
* validate that the block number is legal - the enables us to detect
* and handle a silent filesystem corruption rather than crashing.
*/
if (args.agno >= args.mp->m_sb.sb_agcount)
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 out;
*agbp = args.agbp;
out:
xfs_perag_put(args.pag);
return error;
}
/*
* 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(
struct xfs_trans *tp, /* transaction pointer */
xfs_fsblock_t bno, /* starting block number of extent */
xfs_extlen_t len, /* length of extent */
struct xfs_owner_info *oinfo) /* extent owner */
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_buf *agbp;
xfs_agnumber_t agno = XFS_FSB_TO_AGNO(mp, bno);
xfs_agblock_t agbno = XFS_FSB_TO_AGBNO(mp, bno);
int error;
ASSERT(len != 0);
if (XFS_TEST_ERROR(false, mp,
XFS_ERRTAG_FREE_EXTENT,
XFS_RANDOM_FREE_EXTENT))
return -EIO;
error = xfs_free_extent_fix_freelist(tp, agno, &agbp);
if (error)
return error;
XFS_WANT_CORRUPTED_GOTO(mp, agbno < mp->m_sb.sb_agblocks, err);
/* validate the extent size is legal now we have the agf locked */
XFS_WANT_CORRUPTED_GOTO(mp,
agbno + len <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_length),
err);
error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, 0);
if (error)
goto err;
xfs_extent_busy_insert(tp, agno, agbno, len, 0);
return 0;
err:
xfs_trans_brelse(tp, agbp);
return error;
}