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linux/fs/xfs/libxfs/xfs_alloc.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#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_btree.h"
#include "xfs_rmap.h"
#include "xfs_alloc_btree.h"
#include "xfs_alloc.h"
#include "xfs_extent_busy.h"
#include "xfs_errortag.h"
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_log.h"
#include "xfs_ag_resv.h"
#include "xfs_bmap.h"
extern kmem_zone_t *xfs_bmap_free_item_zone;
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 *);
/*
* Size of the AGFL. For CRC-enabled filesystes we steal a couple of slots in
* the beginning of the block for a proper header with the location information
* and CRC.
*/
unsigned int
xfs_agfl_size(
struct xfs_mount *mp)
{
unsigned int size = mp->m_sb.sb_sectsize;
if (xfs_sb_version_hascrc(&mp->m_sb))
size -= sizeof(struct xfs_agfl);
return size / sizeof(xfs_agblock_t);
}
unsigned int
xfs_refc_block(
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;
}
xfs_extlen_t
xfs_prealloc_blocks(
struct xfs_mount *mp)
{
if (xfs_sb_version_hasreflink(&mp->m_sb))
return xfs_refc_block(mp) + 1;
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.
*
* 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.
*/
unsigned int
xfs_alloc_set_aside(
struct xfs_mount *mp)
{
return mp->m_sb.sb_agcount * (XFS_ALLOC_AGFL_RESERVE + 4);
}
/*
* 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 */
if (xfs_sb_version_hasreflink(&mp->m_sb))
blocks++; /* refcount 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 */
{
int error;
cur->bc_rec.a.ar_startblock = bno;
cur->bc_rec.a.ar_blockcount = len;
error = xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
cur->bc_ag.abt.active = (*stat == 1);
return error;
}
/*
* 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 */
{
int error;
cur->bc_rec.a.ar_startblock = bno;
cur->bc_rec.a.ar_blockcount = len;
error = xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
cur->bc_ag.abt.active = (*stat == 1);
return error;
}
/*
* Lookup the first record less than or equal to [bno, len]
* in the btree given by cur.
*/
int /* error */
xfs_alloc_lookup_le(
struct xfs_btree_cur *cur, /* btree cursor */
xfs_agblock_t bno, /* starting block of extent */
xfs_extlen_t len, /* length of extent */
int *stat) /* success/failure */
{
int error;
cur->bc_rec.a.ar_startblock = bno;
cur->bc_rec.a.ar_blockcount = len;
error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
cur->bc_ag.abt.active = (*stat == 1);
return error;
}
static inline bool
xfs_alloc_cur_active(
struct xfs_btree_cur *cur)
{
return cur && cur->bc_ag.abt.active;
}
/*
* 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 */
{
struct xfs_mount *mp = cur->bc_mp;
xfs_agnumber_t agno = cur->bc_ag.agno;
union xfs_btree_rec *rec;
int error;
error = xfs_btree_get_rec(cur, &rec, stat);
if (error || !(*stat))
return error;
*bno = be32_to_cpu(rec->alloc.ar_startblock);
*len = be32_to_cpu(rec->alloc.ar_blockcount);
if (*len == 0)
goto out_bad_rec;
/* check for valid extent range, including overflow */
if (!xfs_verify_agbno(mp, agno, *bno))
goto out_bad_rec;
if (*bno > *bno + *len)
goto out_bad_rec;
if (!xfs_verify_agbno(mp, agno, *bno + *len - 1))
goto out_bad_rec;
return 0;
out_bad_rec:
xfs_warn(mp,
"%s Freespace BTree record corruption in AG %d detected!",
cur->bc_btnum == XFS_BTNUM_BNO ? "Block" : "Size", agno);
xfs_warn(mp,
"start block 0x%x block count 0x%x", *bno, *len);
return -EFSCORRUPTED;
}
/*
* Compute aligned version of the found extent.
* Takes alignment and min length into account.
*/
STATIC bool
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 */
unsigned *busy_gen)
{
xfs_agblock_t bno = foundbno;
xfs_extlen_t len = foundlen;
xfs_extlen_t diff;
bool busy;
/* Trim busy sections out of found extent */
busy = xfs_extent_busy_trim(args, &bno, &len, busy_gen);
/*
* 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;
}
return busy;
}
/*
* 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 */
int datatype, /* 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 */
bool userdata = datatype & XFS_ALLOC_USERDATA;
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);
ASSERT(args->pag->pagf_freeblks + args->pag->pagf_flcount >=
rlen + args->minleft);
args->len = rlen;
}
/*
* 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;
if (XFS_IS_CORRUPT(mp,
i != 1 ||
nfbno1 != fbno ||
nflen1 != flen))
return -EFSCORRUPTED;
#endif
} else {
if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i)))
return error;
if (XFS_IS_CORRUPT(mp, i != 1))
return -EFSCORRUPTED;
}
/*
* 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;
if (XFS_IS_CORRUPT(mp,
i != 1 ||
nfbno1 != fbno ||
nflen1 != flen))
return -EFSCORRUPTED;
#endif
} else {
if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i)))
return error;
if (XFS_IS_CORRUPT(mp, i != 1))
return -EFSCORRUPTED;
}
#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]);
if (XFS_IS_CORRUPT(mp,
bnoblock->bb_numrecs !=
cntblock->bb_numrecs))
return -EFSCORRUPTED;
}
#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;
if (XFS_IS_CORRUPT(mp, i != 1))
return -EFSCORRUPTED;
/*
* Add new by-size btree entry(s).
*/
if (nfbno1 != NULLAGBLOCK) {
if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &i)))
return error;
if (XFS_IS_CORRUPT(mp, i != 0))
return -EFSCORRUPTED;
if ((error = xfs_btree_insert(cnt_cur, &i)))
return error;
if (XFS_IS_CORRUPT(mp, i != 1))
return -EFSCORRUPTED;
}
if (nfbno2 != NULLAGBLOCK) {
if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
return error;
if (XFS_IS_CORRUPT(mp, i != 0))
return -EFSCORRUPTED;
if ((error = xfs_btree_insert(cnt_cur, &i)))
return error;
if (XFS_IS_CORRUPT(mp, i != 1))
return -EFSCORRUPTED;
}
/*
* 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;
if (XFS_IS_CORRUPT(mp, i != 1))
return -EFSCORRUPTED;
} 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;
if (XFS_IS_CORRUPT(mp, i != 0))
return -EFSCORRUPTED;
if ((error = xfs_btree_insert(bno_cur, &i)))
return error;
if (XFS_IS_CORRUPT(mp, i != 1))
return -EFSCORRUPTED;
}
return 0;
}
static xfs_failaddr_t
xfs_agfl_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
__be32 *agfl_bno = xfs_buf_to_agfl_bno(bp);
int i;
/*
* 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 NULL;
if (!xfs_verify_magic(bp, agfl->agfl_magicnum))
return __this_address;
if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid))
return __this_address;
/*
* 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 __this_address;
for (i = 0; i < xfs_agfl_size(mp); i++) {
if (be32_to_cpu(agfl_bno[i]) != NULLAGBLOCK &&
be32_to_cpu(agfl_bno[i]) >= mp->m_sb.sb_agblocks)
return __this_address;
}
if (!xfs_log_check_lsn(mp, be64_to_cpu(XFS_BUF_TO_AGFL(bp)->agfl_lsn)))
return __this_address;
return NULL;
}
static void
xfs_agfl_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
xfs_failaddr_t fa;
/*
* 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_verifier_error(bp, -EFSBADCRC, __this_address);
else {
fa = xfs_agfl_verify(bp);
if (fa)
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
}
}
static void
xfs_agfl_write_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
struct xfs_buf_log_item *bip = bp->b_log_item;
xfs_failaddr_t fa;
/* no verification of non-crc AGFLs */
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
fa = xfs_agfl_verify(bp);
if (fa) {
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
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",
.magic = { cpu_to_be32(XFS_AGFL_MAGIC), cpu_to_be32(XFS_AGFL_MAGIC) },
.verify_read = xfs_agfl_read_verify,
.verify_write = xfs_agfl_write_verify,
.verify_struct = xfs_agfl_verify,
};
/*
* Read in the allocation group free block array.
*/
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_buf *agbp,
long len)
{
struct xfs_agf *agf = agbp->b_addr;
agbp->b_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))) {
xfs_buf_mark_corrupt(agbp);
return -EFSCORRUPTED;
}
xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
return 0;
}
/*
* Block allocation algorithm and data structures.
*/
struct xfs_alloc_cur {
struct xfs_btree_cur *cnt; /* btree cursors */
struct xfs_btree_cur *bnolt;
struct xfs_btree_cur *bnogt;
xfs_extlen_t cur_len;/* current search length */
xfs_agblock_t rec_bno;/* extent startblock */
xfs_extlen_t rec_len;/* extent length */
xfs_agblock_t bno; /* alloc bno */
xfs_extlen_t len; /* alloc len */
xfs_extlen_t diff; /* diff from search bno */
unsigned int busy_gen;/* busy state */
bool busy;
};
/*
* Set up cursors, etc. in the extent allocation cursor. This function can be
* called multiple times to reset an initialized structure without having to
* reallocate cursors.
*/
static int
xfs_alloc_cur_setup(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur)
{
int error;
int i;
ASSERT(args->alignment == 1 || args->type != XFS_ALLOCTYPE_THIS_BNO);
acur->cur_len = args->maxlen;
acur->rec_bno = 0;
acur->rec_len = 0;
acur->bno = 0;
acur->len = 0;
acur->diff = -1;
acur->busy = false;
acur->busy_gen = 0;
/*
* Perform an initial cntbt lookup to check for availability of maxlen
* extents. If this fails, we'll return -ENOSPC to signal the caller to
* attempt a small allocation.
*/
if (!acur->cnt)
acur->cnt = xfs_allocbt_init_cursor(args->mp, args->tp,
args->agbp, args->agno, XFS_BTNUM_CNT);
error = xfs_alloc_lookup_ge(acur->cnt, 0, args->maxlen, &i);
if (error)
return error;
/*
* Allocate the bnobt left and right search cursors.
*/
if (!acur->bnolt)
acur->bnolt = xfs_allocbt_init_cursor(args->mp, args->tp,
args->agbp, args->agno, XFS_BTNUM_BNO);
if (!acur->bnogt)
acur->bnogt = xfs_allocbt_init_cursor(args->mp, args->tp,
args->agbp, args->agno, XFS_BTNUM_BNO);
return i == 1 ? 0 : -ENOSPC;
}
static void
xfs_alloc_cur_close(
struct xfs_alloc_cur *acur,
bool error)
{
int cur_error = XFS_BTREE_NOERROR;
if (error)
cur_error = XFS_BTREE_ERROR;
if (acur->cnt)
xfs_btree_del_cursor(acur->cnt, cur_error);
if (acur->bnolt)
xfs_btree_del_cursor(acur->bnolt, cur_error);
if (acur->bnogt)
xfs_btree_del_cursor(acur->bnogt, cur_error);
acur->cnt = acur->bnolt = acur->bnogt = NULL;
}
/*
* Check an extent for allocation and track the best available candidate in the
* allocation structure. The cursor is deactivated if it has entered an out of
* range state based on allocation arguments. Optionally return the extent
* extent geometry and allocation status if requested by the caller.
*/
static int
xfs_alloc_cur_check(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur,
struct xfs_btree_cur *cur,
int *new)
{
int error, i;
xfs_agblock_t bno, bnoa, bnew;
xfs_extlen_t len, lena, diff = -1;
bool busy;
unsigned busy_gen = 0;
bool deactivate = false;
bool isbnobt = cur->bc_btnum == XFS_BTNUM_BNO;
*new = 0;
error = xfs_alloc_get_rec(cur, &bno, &len, &i);
if (error)
return error;
if (XFS_IS_CORRUPT(args->mp, i != 1))
return -EFSCORRUPTED;
/*
* Check minlen and deactivate a cntbt cursor if out of acceptable size
* range (i.e., walking backwards looking for a minlen extent).
*/
if (len < args->minlen) {
deactivate = !isbnobt;
goto out;
}
busy = xfs_alloc_compute_aligned(args, bno, len, &bnoa, &lena,
&busy_gen);
acur->busy |= busy;
if (busy)
acur->busy_gen = busy_gen;
/* deactivate a bnobt cursor outside of locality range */
if (bnoa < args->min_agbno || bnoa > args->max_agbno) {
deactivate = isbnobt;
goto out;
}
if (lena < args->minlen)
goto out;
args->len = XFS_EXTLEN_MIN(lena, args->maxlen);
xfs_alloc_fix_len(args);
ASSERT(args->len >= args->minlen);
if (args->len < acur->len)
goto out;
/*
* We have an aligned record that satisfies minlen and beats or matches
* the candidate extent size. Compare locality for near allocation mode.
*/
ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
diff = xfs_alloc_compute_diff(args->agbno, args->len,
args->alignment, args->datatype,
bnoa, lena, &bnew);
if (bnew == NULLAGBLOCK)
goto out;
/*
* Deactivate a bnobt cursor with worse locality than the current best.
*/
if (diff > acur->diff) {
deactivate = isbnobt;
goto out;
}
ASSERT(args->len > acur->len ||
(args->len == acur->len && diff <= acur->diff));
acur->rec_bno = bno;
acur->rec_len = len;
acur->bno = bnew;
acur->len = args->len;
acur->diff = diff;
*new = 1;
/*
* We're done if we found a perfect allocation. This only deactivates
* the current cursor, but this is just an optimization to terminate a
* cntbt search that otherwise runs to the edge of the tree.
*/
if (acur->diff == 0 && acur->len == args->maxlen)
deactivate = true;
out:
if (deactivate)
cur->bc_ag.abt.active = false;
trace_xfs_alloc_cur_check(args->mp, cur->bc_btnum, bno, len, diff,
*new);
return 0;
}
/*
* Complete an allocation of a candidate extent. Remove the extent from both
* trees and update the args structure.
*/
STATIC int
xfs_alloc_cur_finish(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur)
{
struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
int error;
ASSERT(acur->cnt && acur->bnolt);
ASSERT(acur->bno >= acur->rec_bno);
ASSERT(acur->bno + acur->len <= acur->rec_bno + acur->rec_len);
ASSERT(acur->rec_bno + acur->rec_len <= be32_to_cpu(agf->agf_length));
error = xfs_alloc_fixup_trees(acur->cnt, acur->bnolt, acur->rec_bno,
acur->rec_len, acur->bno, acur->len, 0);
if (error)
return error;
args->agbno = acur->bno;
args->len = acur->len;
args->wasfromfl = 0;
trace_xfs_alloc_cur(args);
return 0;
}
/*
* Locality allocation lookup algorithm. This expects a cntbt cursor and uses
* bno optimized lookup to search for extents with ideal size and locality.
*/
STATIC int
xfs_alloc_cntbt_iter(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur)
{
struct xfs_btree_cur *cur = acur->cnt;
xfs_agblock_t bno;
xfs_extlen_t len, cur_len;
int error;
int i;
if (!xfs_alloc_cur_active(cur))
return 0;
/* locality optimized lookup */
cur_len = acur->cur_len;
error = xfs_alloc_lookup_ge(cur, args->agbno, cur_len, &i);
if (error)
return error;
if (i == 0)
return 0;
error = xfs_alloc_get_rec(cur, &bno, &len, &i);
if (error)
return error;
/* check the current record and update search length from it */
error = xfs_alloc_cur_check(args, acur, cur, &i);
if (error)
return error;
ASSERT(len >= acur->cur_len);
acur->cur_len = len;
/*
* We looked up the first record >= [agbno, len] above. The agbno is a
* secondary key and so the current record may lie just before or after
* agbno. If it is past agbno, check the previous record too so long as
* the length matches as it may be closer. Don't check a smaller record
* because that could deactivate our cursor.
*/
if (bno > args->agbno) {
error = xfs_btree_decrement(cur, 0, &i);
if (!error && i) {
error = xfs_alloc_get_rec(cur, &bno, &len, &i);
if (!error && i && len == acur->cur_len)
error = xfs_alloc_cur_check(args, acur, cur,
&i);
}
if (error)
return error;
}
/*
* Increment the search key until we find at least one allocation
* candidate or if the extent we found was larger. Otherwise, double the
* search key to optimize the search. Efficiency is more important here
* than absolute best locality.
*/
cur_len <<= 1;
if (!acur->len || acur->cur_len >= cur_len)
acur->cur_len++;
else
acur->cur_len = cur_len;
return error;
}
/*
* 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(
struct xfs_alloc_arg *args, /* allocation argument structure */
struct xfs_btree_cur *ccur, /* optional 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_agf *agf = args->agbp->b_addr;
int error = 0;
xfs_agblock_t fbno = NULLAGBLOCK;
xfs_extlen_t flen = 0;
int i = 0;
/*
* If a cntbt cursor is provided, try to allocate the largest record in
* the tree. Try the AGFL if the cntbt is empty, otherwise fail the
* allocation. Make sure to respect minleft even when pulling from the
* freelist.
*/
if (ccur)
error = xfs_btree_decrement(ccur, 0, &i);
if (error)
goto error;
if (i) {
error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i);
if (error)
goto error;
if (XFS_IS_CORRUPT(args->mp, i != 1)) {
error = -EFSCORRUPTED;
goto error;
}
goto out;
}
if (args->minlen != 1 || args->alignment != 1 ||
args->resv == XFS_AG_RESV_AGFL ||
be32_to_cpu(agf->agf_flcount) <= args->minleft)
goto out;
error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
if (error)
goto error;
if (fbno == NULLAGBLOCK)
goto out;
xfs_extent_busy_reuse(args->mp, args->agno, fbno, 1,
(args->datatype & XFS_ALLOC_NOBUSY));
if (args->datatype & XFS_ALLOC_USERDATA) {
struct xfs_buf *bp;
error = xfs_trans_get_buf(args->tp, args->mp->m_ddev_targp,
XFS_AGB_TO_DADDR(args->mp, args->agno, fbno),
args->mp->m_bsize, 0, &bp);
if (error)
goto error;
xfs_trans_binval(args->tp, bp);
}
*fbnop = args->agbno = fbno;
*flenp = args->len = 1;
if (XFS_IS_CORRUPT(args->mp, fbno >= be32_to_cpu(agf->agf_length))) {
error = -EFSCORRUPTED;
goto error;
}
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.
*/
error = xfs_rmap_free(args->tp, args->agbp, args->agno, fbno, 1,
&XFS_RMAP_OINFO_AG);
if (error)
goto error;
*stat = 0;
return 0;
out:
/*
* 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;
error:
trace_xfs_alloc_small_error(args);
return error;
}
/*
* 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->resv != XFS_AG_RESV_AGFL);
ASSERT(args->agbno % args->alignment == 0);
/* if not file data, insert new block into the reverse map btree */
if (!xfs_rmap_should_skip_owner_update(&args->oinfo)) {
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->agbp,
-((long)(args->len)));
if (error)
return error;
ASSERT(!xfs_extent_busy_search(args->mp, args->agno,
args->agbno, args->len));
}
xfs_ag_resv_alloc_extent(args->pag, args->resv, args);
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 */
{
struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
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 busy extent */
xfs_extlen_t tlen; /* length of busy extent */
xfs_agblock_t tend; /* end block of busy extent */
int i; /* success/failure of operation */
unsigned busy_gen;
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;
if (XFS_IS_CORRUPT(args->mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
ASSERT(fbno <= args->agbno);
/*
* Check for overlapping busy extents.
*/
tbno = fbno;
tlen = flen;
xfs_extent_busy_trim(args, &tbno, &tlen, &busy_gen);
/*
* 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);
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(agf->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 a given number of btree records in a given direction. Check each
* record against the good extent we've already found.
*/
STATIC int
xfs_alloc_walk_iter(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur,
struct xfs_btree_cur *cur,
bool increment,
bool find_one, /* quit on first candidate */
int count, /* rec count (-1 for infinite) */
int *stat)
{
int error;
int i;
*stat = 0;
/*
* Search so long as the cursor is active or we find a better extent.
* The cursor is deactivated if it extends beyond the range of the
* current allocation candidate.
*/
while (xfs_alloc_cur_active(cur) && count) {
error = xfs_alloc_cur_check(args, acur, cur, &i);
if (error)
return error;
if (i == 1) {
*stat = 1;
if (find_one)
break;
}
if (!xfs_alloc_cur_active(cur))
break;
if (increment)
error = xfs_btree_increment(cur, 0, &i);
else
error = xfs_btree_decrement(cur, 0, &i);
if (error)
return error;
if (i == 0)
cur->bc_ag.abt.active = false;
if (count > 0)
count--;
}
return 0;
}
/*
* Search the by-bno and by-size btrees in parallel in search of an extent with
* ideal locality based on the NEAR mode ->agbno locality hint.
*/
STATIC int
xfs_alloc_ag_vextent_locality(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur,
int *stat)
{
struct xfs_btree_cur *fbcur = NULL;
int error;
int i;
bool fbinc;
ASSERT(acur->len == 0);
ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
*stat = 0;
error = xfs_alloc_lookup_ge(acur->cnt, args->agbno, acur->cur_len, &i);
if (error)
return error;
error = xfs_alloc_lookup_le(acur->bnolt, args->agbno, 0, &i);
if (error)
return error;
error = xfs_alloc_lookup_ge(acur->bnogt, args->agbno, 0, &i);
if (error)
return error;
/*
* Search the bnobt and cntbt in parallel. Search the bnobt left and
* right and lookup the closest extent to the locality hint for each
* extent size key in the cntbt. The entire search terminates
* immediately on a bnobt hit because that means we've found best case
* locality. Otherwise the search continues until the cntbt cursor runs
* off the end of the tree. If no allocation candidate is found at this
* point, give up on locality, walk backwards from the end of the cntbt
* and take the first available extent.
*
* The parallel tree searches balance each other out to provide fairly
* consistent performance for various situations. The bnobt search can
* have pathological behavior in the worst case scenario of larger
* allocation requests and fragmented free space. On the other hand, the
* bnobt is able to satisfy most smaller allocation requests much more
* quickly than the cntbt. The cntbt search can sift through fragmented
* free space and sets of free extents for larger allocation requests
* more quickly than the bnobt. Since the locality hint is just a hint
* and we don't want to scan the entire bnobt for perfect locality, the
* cntbt search essentially bounds the bnobt search such that we can
* find good enough locality at reasonable performance in most cases.
*/
while (xfs_alloc_cur_active(acur->bnolt) ||
xfs_alloc_cur_active(acur->bnogt) ||
xfs_alloc_cur_active(acur->cnt)) {
trace_xfs_alloc_cur_lookup(args);
/*
* Search the bnobt left and right. In the case of a hit, finish
* the search in the opposite direction and we're done.
*/
error = xfs_alloc_walk_iter(args, acur, acur->bnolt, false,
true, 1, &i);
if (error)
return error;
if (i == 1) {
trace_xfs_alloc_cur_left(args);
fbcur = acur->bnogt;
fbinc = true;
break;
}
error = xfs_alloc_walk_iter(args, acur, acur->bnogt, true, true,
1, &i);
if (error)
return error;
if (i == 1) {
trace_xfs_alloc_cur_right(args);
fbcur = acur->bnolt;
fbinc = false;
break;
}
/*
* Check the extent with best locality based on the current
* extent size search key and keep track of the best candidate.
*/
error = xfs_alloc_cntbt_iter(args, acur);
if (error)
return error;
if (!xfs_alloc_cur_active(acur->cnt)) {
trace_xfs_alloc_cur_lookup_done(args);
break;
}
}
/*
* If we failed to find anything due to busy extents, return empty
* handed so the caller can flush and retry. If no busy extents were
* found, walk backwards from the end of the cntbt as a last resort.
*/
if (!xfs_alloc_cur_active(acur->cnt) && !acur->len && !acur->busy) {
error = xfs_btree_decrement(acur->cnt, 0, &i);
if (error)
return error;
if (i) {
acur->cnt->bc_ag.abt.active = true;
fbcur = acur->cnt;
fbinc = false;
}
}
/*
* Search in the opposite direction for a better entry in the case of
* a bnobt hit or walk backwards from the end of the cntbt.
*/
if (fbcur) {
error = xfs_alloc_walk_iter(args, acur, fbcur, fbinc, true, -1,
&i);
if (error)
return error;
}
if (acur->len)
*stat = 1;
return 0;
}
/* Check the last block of the cnt btree for allocations. */
static int
xfs_alloc_ag_vextent_lastblock(
struct xfs_alloc_arg *args,
struct xfs_alloc_cur *acur,
xfs_agblock_t *bno,
xfs_extlen_t *len,
bool *allocated)
{
int error;
int i;
#ifdef DEBUG
/* Randomly don't execute the first algorithm. */
if (prandom_u32() & 1)
return 0;
#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 (*len || args->alignment > 1) {
acur->cnt->bc_ptrs[0] = 1;
do {
error = xfs_alloc_get_rec(acur->cnt, bno, len, &i);
if (error)
return error;
if (XFS_IS_CORRUPT(args->mp, i != 1))
return -EFSCORRUPTED;
if (*len >= args->minlen)
break;
error = xfs_btree_increment(acur->cnt, 0, &i);
if (error)
return error;
} while (i);
ASSERT(*len >= args->minlen);
if (!i)
return 0;
}
error = xfs_alloc_walk_iter(args, acur, acur->cnt, true, false, -1, &i);
if (error)
return error;
/*
* It didn't work. We COULD be in a case where there's a good record
* somewhere, so try again.
*/
if (acur->len == 0)
return 0;
trace_xfs_alloc_near_first(args);
*allocated = true;
return 0;
}
/*
* 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
xfs_alloc_ag_vextent_near(
struct xfs_alloc_arg *args)
{
struct xfs_alloc_cur acur = {};
int error; /* error code */
int i; /* result code, temporary */
xfs_agblock_t bno;
xfs_extlen_t len;
/* handle uninitialized 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:
len = 0;
/*
* Set up cursors and see if there are any free extents as big as
* maxlen. If not, pick the last entry in the tree unless the tree is
* empty.
*/
error = xfs_alloc_cur_setup(args, &acur);
if (error == -ENOSPC) {
error = xfs_alloc_ag_vextent_small(args, acur.cnt, &bno,
&len, &i);
if (error)
goto out;
if (i == 0 || len == 0) {
trace_xfs_alloc_near_noentry(args);
goto out;
}
ASSERT(i == 1);
} else if (error) {
goto out;
}
/*
* 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(acur.cnt, 0)) {
bool allocated = false;
error = xfs_alloc_ag_vextent_lastblock(args, &acur, &bno, &len,
&allocated);
if (error)
goto out;
if (allocated)
goto alloc_finish;
}
/*
* Second algorithm. Combined cntbt and bnobt search to find ideal
* locality.
*/
error = xfs_alloc_ag_vextent_locality(args, &acur, &i);
if (error)
goto out;
/*
* If we couldn't get anything, give up.
*/
if (!acur.len) {
if (acur.busy) {
trace_xfs_alloc_near_busy(args);
xfs_extent_busy_flush(args->mp, args->pag,
acur.busy_gen);
goto restart;
}
trace_xfs_alloc_size_neither(args);
args->agbno = NULLAGBLOCK;
goto out;
}
alloc_finish:
/* fix up btrees on a successful allocation */
error = xfs_alloc_cur_finish(args, &acur);
out:
xfs_alloc_cur_close(&acur, 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 */
{
struct xfs_agf *agf = args->agbp->b_addr;
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 */
bool busy;
unsigned busy_gen;
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;
busy = false;
/*
* 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 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) {
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);
busy = xfs_alloc_compute_aligned(args, fbno, flen, &rbno,
&rlen, &busy_gen);
} else {
/*
* Search for a non-busy extent that is large enough.
*/
for (;;) {
error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
if (error)
goto error0;
if (XFS_IS_CORRUPT(args->mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
busy = xfs_alloc_compute_aligned(args, fbno, flen,
&rbno, &rlen, &busy_gen);
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.
*/
xfs_btree_del_cursor(cnt_cur,
XFS_BTREE_NOERROR);
trace_xfs_alloc_size_busy(args);
xfs_extent_busy_flush(args->mp,
args->pag, busy_gen);
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);
if (XFS_IS_CORRUPT(args->mp,
rlen != 0 &&
(rlen > flen ||
rbno + rlen > fbno + flen))) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(args->mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
if (flen < bestrlen)
break;
busy = xfs_alloc_compute_aligned(args, fbno, flen,
&rbno, &rlen, &busy_gen);
rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
if (XFS_IS_CORRUPT(args->mp,
rlen != 0 &&
(rlen > flen ||
rbno + rlen > fbno + flen))) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(args->mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
rlen = bestrlen;
rbno = bestrbno;
flen = bestflen;
fbno = bestfbno;
}
args->wasfromfl = 0;
/*
* Fix up the length.
*/
args->len = rlen;
if (rlen < args->minlen) {
if (busy) {
xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
trace_xfs_alloc_size_busy(args);
xfs_extent_busy_flush(args->mp, args->pag, busy_gen);
goto restart;
}
goto out_nominleft;
}
xfs_alloc_fix_len(args);
rlen = args->len;
if (XFS_IS_CORRUPT(args->mp, rlen > flen)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(args->mp,
args->agbno + args->len >
be32_to_cpu(agf->agf_length))) {
error = -EFSCORRUPTED;
goto 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;
}
/*
* Free the extent starting at agno/bno for length.
*/
STATIC int
xfs_free_ag_extent(
struct xfs_trans *tp,
struct xfs_buf *agbp,
xfs_agnumber_t agno,
xfs_agblock_t bno,
xfs_extlen_t len,
const struct xfs_owner_info *oinfo,
enum xfs_ag_resv_type type)
{
struct xfs_mount *mp;
struct xfs_btree_cur *bno_cur;
struct xfs_btree_cur *cnt_cur;
xfs_agblock_t gtbno; /* start of right neighbor */
xfs_extlen_t gtlen; /* length of right neighbor */
xfs_agblock_t ltbno; /* start of left neighbor */
xfs_extlen_t ltlen; /* length of left neighbor */
xfs_agblock_t nbno; /* new starting block of freesp */
xfs_extlen_t nlen; /* new length of freespace */
int haveleft; /* have a left neighbor */
int haveright; /* have a right neighbor */
int i;
int error;
bno_cur = cnt_cur = NULL;
mp = tp->t_mountp;
if (!xfs_rmap_should_skip_owner_update(oinfo)) {
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;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto 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.
*/
if (XFS_IS_CORRUPT(mp, ltbno + ltlen > bno)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto 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.
*/
if (XFS_IS_CORRUPT(mp, bno + len > gtbno)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
/*
* Delete the old by-size entry on the right.
*/
if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
/*
* Delete the old by-block entry for the right block.
*/
if ((error = xfs_btree_delete(bno_cur, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
/*
* Move the by-block cursor back to the left neighbor.
*/
if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp,
i != 1 ||
xxbno != ltbno ||
xxlen != ltlen)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
if ((error = xfs_btree_delete(cnt_cur, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto 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;
if (XFS_IS_CORRUPT(mp, i != 0)) {
error = -EFSCORRUPTED;
goto error0;
}
if ((error = xfs_btree_insert(cnt_cur, &i)))
goto error0;
if (XFS_IS_CORRUPT(mp, i != 1)) {
error = -EFSCORRUPTED;
goto error0;
}
xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
cnt_cur = NULL;
/*
* Update the freespace totals in the ag and superblock.
*/
error = xfs_alloc_update_counters(tp, agbp, len);
xfs_ag_resv_free_extent(agbp->b_pag, type, tp, len);
if (error)
goto error0;
XFS_STATS_INC(mp, xs_freex);
XFS_STATS_ADD(mp, xs_freeb, len);
trace_xfs_free_extent(mp, agno, bno, len, type, haveleft, haveright);
return 0;
error0:
trace_xfs_free_extent(mp, agno, bno, len, type, -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->m_alloc_mnr,
(mp->m_sb.sb_agblocks + 1) / 2);
}
/*
* Find the length of the longest extent in an AG. The 'need' parameter
* specifies how much space we're going to need for the AGFL and the
* 'reserved' parameter tells us how many blocks in this AG are reserved for
* other callers.
*/
xfs_extlen_t
xfs_alloc_longest_free_extent(
struct xfs_perag *pag,
xfs_extlen_t need,
xfs_extlen_t reserved)
{
xfs_extlen_t delta = 0;
/*
* If the AGFL needs a recharge, we'll have to subtract that from the
* longest extent.
*/
if (need > pag->pagf_flcount)
delta = need - pag->pagf_flcount;
/*
* If we cannot maintain others' reservations with space from the
* not-longest freesp extents, we'll have to subtract /that/ from
* the longest extent too.
*/
if (pag->pagf_freeblks - pag->pagf_longest < reserved)
delta += reserved - (pag->pagf_freeblks - pag->pagf_longest);
/*
* If the longest extent is long enough to satisfy all the
* reservations and AGFL rules in place, we can return this extent.
*/
if (pag->pagf_longest > delta)
return min_t(xfs_extlen_t, pag->pag_mount->m_ag_max_usable,
pag->pagf_longest - delta);
/* Otherwise, let the caller try for 1 block if there's space. */
return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
}
/*
* Compute the minimum length of the AGFL in the given AG. If @pag is NULL,
* return the largest possible minimum length.
*/
unsigned int
xfs_alloc_min_freelist(
struct xfs_mount *mp,
struct xfs_perag *pag)
{
/* AG btrees have at least 1 level. */
static const uint8_t fake_levels[XFS_BTNUM_AGF] = {1, 1, 1};
const uint8_t *levels = pag ? pag->pagf_levels : fake_levels;
unsigned int min_free;
ASSERT(mp->m_ag_maxlevels > 0);
/* space needed by-bno freespace btree */
min_free = min_t(unsigned int, levels[XFS_BTNUM_BNOi] + 1,
mp->m_ag_maxlevels);
/* space needed by-size freespace btree */
min_free += min_t(unsigned int, 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, 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 alloc_len, longest;
xfs_extlen_t reservation; /* blocks that are still reserved */
int available;
xfs_extlen_t agflcount;
if (flags & XFS_ALLOC_FLAG_FREEING)
return true;
reservation = xfs_ag_resv_needed(pag, args->resv);
/* do we have enough contiguous free space for the allocation? */
alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop;
longest = xfs_alloc_longest_free_extent(pag, min_free, reservation);
if (longest < alloc_len)
return false;
/*
* Do we have enough free space remaining for the allocation? Don't
* account extra agfl blocks because we are about to defer free them,
* making them unavailable until the current transaction commits.
*/
agflcount = min_t(xfs_extlen_t, pag->pagf_flcount, min_free);
available = (int)(pag->pagf_freeblks + agflcount -
reservation - min_free - args->minleft);
if (available < (int)max(args->total, alloc_len))
return false;
/*
* Clamp maxlen to the amount of free space available for the actual
* extent allocation.
*/
if (available < (int)args->maxlen && !(flags & XFS_ALLOC_FLAG_CHECK)) {
args->maxlen = available;
ASSERT(args->maxlen > 0);
ASSERT(args->maxlen >= args->minlen);
}
return true;
}
int
xfs_free_agfl_block(
struct xfs_trans *tp,
xfs_agnumber_t agno,
xfs_agblock_t agbno,
struct xfs_buf *agbp,
struct xfs_owner_info *oinfo)
{
int error;
struct xfs_buf *bp;
error = xfs_free_ag_extent(tp, agbp, agno, agbno, 1, oinfo,
XFS_AG_RESV_AGFL);
if (error)
return error;
error = xfs_trans_get_buf(tp, tp->t_mountp->m_ddev_targp,
XFS_AGB_TO_DADDR(tp->t_mountp, agno, agbno),
tp->t_mountp->m_bsize, 0, &bp);
if (error)
return error;
xfs_trans_binval(tp, bp);
return 0;
}
/*
* Check the agfl fields of the agf for inconsistency or corruption. The purpose
* is to detect an agfl header padding mismatch between current and early v5
* kernels. This problem manifests as a 1-slot size difference between the
* on-disk flcount and the active [first, last] range of a wrapped agfl. This
* may also catch variants of agfl count corruption unrelated to padding. Either
* way, we'll reset the agfl and warn the user.
*
* Return true if a reset is required before the agfl can be used, false
* otherwise.
*/
static bool
xfs_agfl_needs_reset(
struct xfs_mount *mp,
struct xfs_agf *agf)
{
uint32_t f = be32_to_cpu(agf->agf_flfirst);
uint32_t l = be32_to_cpu(agf->agf_fllast);
uint32_t c = be32_to_cpu(agf->agf_flcount);
int agfl_size = xfs_agfl_size(mp);
int active;
/* no agfl header on v4 supers */
if (!xfs_sb_version_hascrc(&mp->m_sb))
return false;
/*
* The agf read verifier catches severe corruption of these fields.
* Repeat some sanity checks to cover a packed -> unpacked mismatch if
* the verifier allows it.
*/
if (f >= agfl_size || l >= agfl_size)
return true;
if (c > agfl_size)
return true;
/*
* Check consistency between the on-disk count and the active range. An
* agfl padding mismatch manifests as an inconsistent flcount.
*/
if (c && l >= f)
active = l - f + 1;
else if (c)
active = agfl_size - f + l + 1;
else
active = 0;
return active != c;
}
/*
* Reset the agfl to an empty state. Ignore/drop any existing blocks since the
* agfl content cannot be trusted. Warn the user that a repair is required to
* recover leaked blocks.
*
* The purpose of this mechanism is to handle filesystems affected by the agfl
* header padding mismatch problem. A reset keeps the filesystem online with a
* relatively minor free space accounting inconsistency rather than suffer the
* inevitable crash from use of an invalid agfl block.
*/
static void
xfs_agfl_reset(
struct xfs_trans *tp,
struct xfs_buf *agbp,
struct xfs_perag *pag)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_agf *agf = agbp->b_addr;
ASSERT(pag->pagf_agflreset);
trace_xfs_agfl_reset(mp, agf, 0, _RET_IP_);
xfs_warn(mp,
"WARNING: Reset corrupted AGFL on AG %u. %d blocks leaked. "
"Please unmount and run xfs_repair.",
pag->pag_agno, pag->pagf_flcount);
agf->agf_flfirst = 0;
agf->agf_fllast = cpu_to_be32(xfs_agfl_size(mp) - 1);
agf->agf_flcount = 0;
xfs_alloc_log_agf(tp, agbp, XFS_AGF_FLFIRST | XFS_AGF_FLLAST |
XFS_AGF_FLCOUNT);
pag->pagf_flcount = 0;
pag->pagf_agflreset = false;
}
/*
* Defer an AGFL block free. This is effectively equivalent to
* xfs_bmap_add_free() with some special handling particular to AGFL blocks.
*
* Deferring AGFL frees helps prevent log reservation overruns due to too many
* allocation operations in a transaction. AGFL frees are prone to this problem
* because for one they are always freed one at a time. Further, an immediate
* AGFL block free can cause a btree join and require another block free before
* the real allocation can proceed. Deferring the free disconnects freeing up
* the AGFL slot from freeing the block.
*/
STATIC void
xfs_defer_agfl_block(
struct xfs_trans *tp,
xfs_agnumber_t agno,
xfs_fsblock_t agbno,
struct xfs_owner_info *oinfo)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_extent_free_item *new; /* new element */
ASSERT(xfs_bmap_free_item_zone != NULL);
ASSERT(oinfo != NULL);
new = kmem_cache_alloc(xfs_bmap_free_item_zone,
GFP_KERNEL | __GFP_NOFAIL);
new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno);
new->xefi_blockcount = 1;
new->xefi_oinfo = *oinfo;
new->xefi_skip_discard = false;
trace_xfs_agfl_free_defer(mp, agno, 0, agbno, 1);
xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_AGFL_FREE, &new->xefi_list);
}
/*
* 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;
/* deferred ops (AGFL block frees) require permanent transactions */
ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
if (!pag->pagf_init) {
error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
if (error) {
/* Couldn't lock the AGF so skip this AG. */
if (error == -EAGAIN)
error = 0;
goto out_no_agbp;
}
}
/*
* 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->datatype & XFS_ALLOC_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 |
XFS_ALLOC_FLAG_CHECK))
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) {
/* Couldn't lock the AGF so skip this AG. */
if (error == -EAGAIN)
error = 0;
goto out_no_agbp;
}
}
/* reset a padding mismatched agfl before final free space check */
if (pag->pagf_agflreset)
xfs_agfl_reset(tp, agbp, pag);
/* 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));
/* struct copy below */
if (flags & XFS_ALLOC_FLAG_NORMAP)
targs.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
else
targs.oinfo = XFS_RMAP_OINFO_AG;
while (!(flags & XFS_ALLOC_FLAG_NOSHRINK) && pag->pagf_flcount > need) {
error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
if (error)
goto out_agbp_relse;
/* defer agfl frees */
xfs_defer_agfl_block(tp, args->agno, bno, &targs.oinfo);
}
targs.tp = tp;
targs.mp = mp;
targs.agbp = agbp;
targs.agno = args->agno;
targs.alignment = targs.minlen = targs.prod = 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;
targs.resv = XFS_AG_RESV_AGFL;
/* 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 */
{
struct xfs_agf *agf = agbp->b_addr;
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.
*/
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(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 = agbp->b_pag;
ASSERT(!pag->pagf_agflreset);
be32_add_cpu(&agf->agf_flcount, -1);
xfs_trans_agflist_delta(tp, -1);
pag->pagf_flcount--;
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),
offsetof(xfs_agf_t, agf_refcount_blocks),
offsetof(xfs_agf_t, agf_refcount_root),
offsetof(xfs_agf_t, agf_refcount_level),
/* needed so that we don't log the whole rest of the structure: */
offsetof(xfs_agf_t, agf_spare64),
sizeof(xfs_agf_t)
};
trace_xfs_agf(tp->t_mountp, bp->b_addr, 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;
error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp);
if (!error)
xfs_trans_brelse(tp, bp);
return error;
}
/*
* 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 */
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_agf *agf = agbp->b_addr;
__be32 *blockp;/* pointer to array entry */
int error;
int logflags;
xfs_perag_t *pag; /* per allocation group data */
__be32 *agfl_bno;
int startoff;
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 = agbp->b_pag;
ASSERT(!pag->pagf_agflreset);
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_alloc_log_agf(tp, agbp, logflags);
ASSERT(be32_to_cpu(agf->agf_flcount) <= xfs_agfl_size(mp));
agfl_bno = xfs_buf_to_agfl_bno(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 xfs_failaddr_t
xfs_agf_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
struct xfs_agf *agf = bp->b_addr;
if (xfs_sb_version_hascrc(&mp->m_sb)) {
if (!uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid))
return __this_address;
if (!xfs_log_check_lsn(mp, be64_to_cpu(agf->agf_lsn)))
return __this_address;
}
if (!xfs_verify_magic(bp, agf->agf_magicnum))
return __this_address;
if (!(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 __this_address;
if (be32_to_cpu(agf->agf_length) > mp->m_sb.sb_dblocks)
return __this_address;
if (be32_to_cpu(agf->agf_freeblks) < be32_to_cpu(agf->agf_longest) ||
be32_to_cpu(agf->agf_freeblks) > be32_to_cpu(agf->agf_length))
return __this_address;
if (be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) < 1 ||
be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) < 1 ||
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 __this_address;
if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
(be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) < 1 ||
be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS))
return __this_address;
if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
be32_to_cpu(agf->agf_rmap_blocks) > be32_to_cpu(agf->agf_length))
return __this_address;
/*
* 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 __this_address;
if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
be32_to_cpu(agf->agf_btreeblks) > be32_to_cpu(agf->agf_length))
return __this_address;
if (xfs_sb_version_hasreflink(&mp->m_sb) &&
be32_to_cpu(agf->agf_refcount_blocks) >
be32_to_cpu(agf->agf_length))
return __this_address;
if (xfs_sb_version_hasreflink(&mp->m_sb) &&
(be32_to_cpu(agf->agf_refcount_level) < 1 ||
be32_to_cpu(agf->agf_refcount_level) > XFS_BTREE_MAXLEVELS))
return __this_address;
return NULL;
}
static void
xfs_agf_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
xfs_failaddr_t fa;
if (xfs_sb_version_hascrc(&mp->m_sb) &&
!xfs_buf_verify_cksum(bp, XFS_AGF_CRC_OFF))
xfs_verifier_error(bp, -EFSBADCRC, __this_address);
else {
fa = xfs_agf_verify(bp);
if (XFS_TEST_ERROR(fa, mp, XFS_ERRTAG_ALLOC_READ_AGF))
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
}
}
static void
xfs_agf_write_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
struct xfs_buf_log_item *bip = bp->b_log_item;
struct xfs_agf *agf = bp->b_addr;
xfs_failaddr_t fa;
fa = xfs_agf_verify(bp);
if (fa) {
xfs_verifier_error(bp, -EFSCORRUPTED, fa);
return;
}
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
if (bip)
agf->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",
.magic = { cpu_to_be32(XFS_AGF_MAGIC), cpu_to_be32(XFS_AGF_MAGIC) },
.verify_read = xfs_agf_read_verify,
.verify_write = xfs_agf_write_verify,
.verify_struct = xfs_agf_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;
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);
/* We don't support trylock when freeing. */
ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=
(XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));
ASSERT(agno != NULLAGNUMBER);
error = xfs_read_agf(mp, tp, agno,
(flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
bpp);
if (error)
return error;
ASSERT(!(*bpp)->b_error);
agf = (*bpp)->b_addr;
pag = (*bpp)->b_pag;
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]);
pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
pag->pagf_init = 1;
pag->pagf_agflreset = xfs_agfl_needs_reset(mp, agf);
}
#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
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(
struct xfs_alloc_arg *args) /* allocation argument structure */
{
xfs_agblock_t agsize; /* allocation group size */
int error;
int flags; /* XFS_ALLOC_FLAG_... locking flags */
struct xfs_mount *mp; /* mount structure pointer */
xfs_agnumber_t sagno; /* starting allocation group number */
xfs_alloctype_t type; /* input allocation type */
int bump_rotor = 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;
}
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);
error = xfs_alloc_fix_freelist(args, 0);
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->datatype & 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_FIRST_AG:
/*
* Rotate through the allocation groups looking for a winner.
*/
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 {
/*
* 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);
error = xfs_alloc_fix_freelist(args, flags);
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->tp->t_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 (flags == 0) {
args->agbno = NULLAGBLOCK;
trace_xfs_alloc_vextent_allfailed(args);
break;
}
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) {
if (args->agno == sagno)
mp->m_agfrotor = (mp->m_agfrotor + 1) %
(mp->m_sb.sb_agcount * rotorstep);
else
mp->m_agfrotor = (args->agno * rotorstep + 1) %
(mp->m_sb.sb_agcount * rotorstep);
}
break;
default:
ASSERT(0);
/* NOTREACHED */
}
if (args->agbno == NULLAGBLOCK)
args->fsbno = NULLFSBLOCK;
else {
args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
#ifdef DEBUG
ASSERT(args->len >= args->minlen);
ASSERT(args->len <= args->maxlen);
ASSERT(args->agbno % args->alignment == 0);
XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno),
args->len);
#endif
}
xfs_perag_put(args->pag);
return 0;
error0:
xfs_perag_put(args->pag);
return error;
}
/* 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
__xfs_free_extent(
struct xfs_trans *tp,
xfs_fsblock_t bno,
xfs_extlen_t len,
const struct xfs_owner_info *oinfo,
enum xfs_ag_resv_type type,
bool skip_discard)
{
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);
struct xfs_agf *agf;
int error;
unsigned int busy_flags = 0;
ASSERT(len != 0);
ASSERT(type != XFS_AG_RESV_AGFL);
if (XFS_TEST_ERROR(false, mp,
XFS_ERRTAG_FREE_EXTENT))
return -EIO;
error = xfs_free_extent_fix_freelist(tp, agno, &agbp);
if (error)
return error;
agf = agbp->b_addr;
if (XFS_IS_CORRUPT(mp, agbno >= mp->m_sb.sb_agblocks)) {
error = -EFSCORRUPTED;
goto err;
}
/* validate the extent size is legal now we have the agf locked */
if (XFS_IS_CORRUPT(mp, agbno + len > be32_to_cpu(agf->agf_length))) {
error = -EFSCORRUPTED;
goto err;
}
error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, type);
if (error)
goto err;
if (skip_discard)
busy_flags |= XFS_EXTENT_BUSY_SKIP_DISCARD;
xfs_extent_busy_insert(tp, agno, agbno, len, busy_flags);
return 0;
err:
xfs_trans_brelse(tp, agbp);
return error;
}
struct xfs_alloc_query_range_info {
xfs_alloc_query_range_fn fn;
void *priv;
};
/* Format btree record and pass to our callback. */
STATIC int
xfs_alloc_query_range_helper(
struct xfs_btree_cur *cur,
union xfs_btree_rec *rec,
void *priv)
{
struct xfs_alloc_query_range_info *query = priv;
struct xfs_alloc_rec_incore irec;
irec.ar_startblock = be32_to_cpu(rec->alloc.ar_startblock);
irec.ar_blockcount = be32_to_cpu(rec->alloc.ar_blockcount);
return query->fn(cur, &irec, query->priv);
}
/* Find all free space within a given range of blocks. */
int
xfs_alloc_query_range(
struct xfs_btree_cur *cur,
struct xfs_alloc_rec_incore *low_rec,
struct xfs_alloc_rec_incore *high_rec,
xfs_alloc_query_range_fn fn,
void *priv)
{
union xfs_btree_irec low_brec;
union xfs_btree_irec high_brec;
struct xfs_alloc_query_range_info query;
ASSERT(cur->bc_btnum == XFS_BTNUM_BNO);
low_brec.a = *low_rec;
high_brec.a = *high_rec;
query.priv = priv;
query.fn = fn;
return xfs_btree_query_range(cur, &low_brec, &high_brec,
xfs_alloc_query_range_helper, &query);
}
/* Find all free space records. */
int
xfs_alloc_query_all(
struct xfs_btree_cur *cur,
xfs_alloc_query_range_fn fn,
void *priv)
{
struct xfs_alloc_query_range_info query;
ASSERT(cur->bc_btnum == XFS_BTNUM_BNO);
query.priv = priv;
query.fn = fn;
return xfs_btree_query_all(cur, xfs_alloc_query_range_helper, &query);
}
/* Is there a record covering a given extent? */
int
xfs_alloc_has_record(
struct xfs_btree_cur *cur,
xfs_agblock_t bno,
xfs_extlen_t len,
bool *exists)
{
union xfs_btree_irec low;
union xfs_btree_irec high;
memset(&low, 0, sizeof(low));
low.a.ar_startblock = bno;
memset(&high, 0xFF, sizeof(high));
high.a.ar_startblock = bno + len - 1;
return xfs_btree_has_record(cur, &low, &high, exists);
}
/*
* Walk all the blocks in the AGFL. The @walk_fn can return any negative
* error code or XFS_ITER_*.
*/
int
xfs_agfl_walk(
struct xfs_mount *mp,
struct xfs_agf *agf,
struct xfs_buf *agflbp,
xfs_agfl_walk_fn walk_fn,
void *priv)
{
__be32 *agfl_bno;
unsigned int i;
int error;
agfl_bno = xfs_buf_to_agfl_bno(agflbp);
i = be32_to_cpu(agf->agf_flfirst);
/* Nothing to walk in an empty AGFL. */
if (agf->agf_flcount == cpu_to_be32(0))
return 0;
/* Otherwise, walk from first to last, wrapping as needed. */
for (;;) {
error = walk_fn(mp, be32_to_cpu(agfl_bno[i]), priv);
if (error)
return error;
if (i == be32_to_cpu(agf->agf_fllast))
break;
if (++i == xfs_agfl_size(mp))
i = 0;
}
return 0;
}
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