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linux/fs/xfs/libxfs/xfs_alloc.c
Brian Foster dc8e69bd72 xfs: optimize near mode bnobt scans with concurrent cntbt lookups 
The near mode fallback algorithm consists of a left/right scan of
the bnobt. This algorithm has very poor breakdown characteristics
under worst case free space fragmentation conditions. If a suitable
extent is far enough from the locality hint, each allocation may
scan most or all of the bnobt before it completes. This causes
pathological behavior and extremely high allocation latencies.

While locality is important to near mode allocations, it is not so
important as to incur pathological allocation latency to provide the
asolute best available locality for every allocation. If the
allocation is large enough or far enough away, there is a point of
diminishing returns. As such, we can bound the overall operation by
including an iterative cntbt lookup in the broader search. The cntbt
lookup is optimized to immediately find the extent with best
locality for the given size on each iteration. Since the cntbt is
indexed by extent size, the lookup repeats with a variably
aggressive increasing search key size until it runs off the edge of
the tree.

This approach provides a natural balance between the two algorithms
for various situations. For example, the bnobt scan is able to
satisfy smaller allocations such as for inode chunks or btree blocks
more quickly where the cntbt search may have to search through a
large set of extent sizes when the search key starts off small
relative to the largest extent in the tree. On the other hand, the
cntbt search more deterministically covers the set of suitable
extents for larger data extent allocation requests that the bnobt
scan may have to search the entire tree to locate.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-10-21 09:04:58 -07:00

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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_private.a.priv.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_private.a.priv.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_private.a.priv.abt.active = (*stat == 1);
return error;
}
static inline bool
xfs_alloc_cur_active(
struct xfs_btree_cur *cur)
{
return cur && cur->bc_private.a.priv.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_private.a.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 = xfs_alloc_is_userdata(datatype);
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;
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 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);
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->agfl_bno[i]) != NULLAGBLOCK &&
be32_to_cpu(agfl->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_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;
}
/*
* 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;
XFS_WANT_CORRUPTED_RETURN(args->mp, i == 1);
/*
* 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_private.a.priv.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)
{
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(XFS_BUF_TO_AGF(args->agbp)->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 */
{
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;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error);
goto out;
}
if (args->minlen != 1 || args->alignment != 1 ||
args->resv == XFS_AG_RESV_AGFL ||
(be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->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,
xfs_alloc_allow_busy_reuse(args->datatype));
if (xfs_alloc_is_userdata(args->datatype)) {
struct xfs_buf *bp;
bp = xfs_btree_get_bufs(args->mp, args->tp, args->agno, fbno);
if (!bp) {
error = -EFSCORRUPTED;
goto error;
}
xfs_trans_binval(args->tp, bp);
}
*fbnop = args->agbno = fbno;
*flenp = args->len = 1;
XFS_WANT_CORRUPTED_GOTO(args->mp,
fbno < be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length),
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->pag,
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 */
{
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;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, 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(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 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_private.a.priv.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_private.a.priv.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;
}
/*
* 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;
#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:
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.
* 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(acur.cnt, 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 (len || args->alignment > 1) {
acur.cnt->bc_ptrs[0] = 1;
do {
error = xfs_alloc_get_rec(acur.cnt, &bno, &len,
&i);
if (error)
goto out;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, out);
if (len >= args->minlen)
break;
error = xfs_btree_increment(acur.cnt, 0, &i);
if (error)
goto out;
} while (i);
ASSERT(len >= args->minlen);
if (!i)
break;
}
error = xfs_alloc_walk_iter(args, &acur, acur.cnt, true, false,
-1, &i);
if (error)
goto out;
/*
* It didn't work. We COULD be in a case where
* there's a good record somewhere, so try again.
*/
if (acur.len == 0)
break;
trace_xfs_alloc_near_first(args);
goto alloc;
}
/*
* 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:
/* 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 */
{
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;
XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, 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);
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;
busy = xfs_alloc_compute_aligned(args, fbno, flen,
&rbno, &rlen, &busy_gen);
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 (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;
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;
}
/*
* 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_perag *pag;
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;
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_ag_resv_free_extent(pag, type, tp, len);
xfs_perag_put(pag);
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 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;
}
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 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;
bp = xfs_btree_get_bufs(tp->t_mountp, tp, agno, agbno);
if (!bp)
return -EFSCORRUPTED;
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 = XFS_BUF_TO_AGF(agbp);
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_zone_alloc(xfs_bmap_free_item_zone, 0);
new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno);
new->xefi_blockcount = 1;
new->xefi_oinfo = *oinfo;
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)
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 && xfs_alloc_is_userdata(args->datatype) &&
(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)
goto out_no_agbp;
if (!agbp) {
ASSERT(flags & XFS_ALLOC_FLAG_TRYLOCK);
ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
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 */
{
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));
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_perag_put(pag);
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, 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));
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_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 xfs_failaddr_t
xfs_agf_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_mount;
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 __this_address;
if (!xfs_log_check_lsn(mp,
be64_to_cpu(XFS_BUF_TO_AGF(bp)->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_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;
/*
* 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_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;
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)
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",
.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;
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]);
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
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(
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
/* Zero the extent if we were asked to do so */
if (args->datatype & 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
__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);
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;
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, 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(mp, 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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