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Diffstat (limited to '')
| -rw-r--r-- | fs/xfs/libxfs/xfs_alloc.c | 3568 |
1 files changed, 3568 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c new file mode 100644 index 000000000..de79f5d07 --- /dev/null +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -0,0 +1,3568 @@ +// 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_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.h" +#include "xfs_ag_resv.h" +#include "xfs_bmap.h" + +struct kmem_cache *xfs_extfree_item_cache; + +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_has_crc(mp)) + size -= sizeof(struct xfs_agfl); + + return size / sizeof(xfs_agblock_t); +} + +unsigned int +xfs_refc_block( + struct xfs_mount *mp) +{ + if (xfs_has_rmapbt(mp)) + return XFS_RMAP_BLOCK(mp) + 1; + if (xfs_has_finobt(mp)) + return XFS_FIBT_BLOCK(mp) + 1; + return XFS_IBT_BLOCK(mp) + 1; +} + +xfs_extlen_t +xfs_prealloc_blocks( + struct xfs_mount *mp) +{ + if (xfs_has_reflink(mp)) + return xfs_refc_block(mp) + 1; + if (xfs_has_rmapbt(mp)) + return XFS_RMAP_BLOCK(mp) + 1; + if (xfs_has_finobt(mp)) + return XFS_FIBT_BLOCK(mp) + 1; + return XFS_IBT_BLOCK(mp) + 1; +} + +/* + * The number of blocks per AG that we withhold from xfs_mod_fdblocks to + * guarantee that we can refill the AGFL prior to allocating space in a nearly + * full AG. Although the space described by the free space btrees, the + * blocks used by the freesp btrees themselves, and the blocks owned by the + * AGFL are counted in the ondisk fdblocks, it's a mistake to let the ondisk + * free space in the AG drop so low that the free space btrees cannot refill an + * empty AGFL up to the minimum level. Rather than grind through empty AGs + * until the fs goes down, we subtract this many AG blocks from the incore + * fdblocks to ensure user allocation does not overcommit the space the + * filesystem needs for the AGFLs. The rmap btree uses a per-AG reservation to + * withhold space from xfs_mod_fdblocks, so we do not account for that here. + */ +#define XFS_ALLOCBT_AGFL_RESERVE 4 + +/* + * Compute the number of blocks that we set aside to guarantee the ability to + * refill the AGFL and handle a full bmap btree split. + * + * 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. + * + * For each AG, we need to reserve enough blocks to replenish a totally empty + * AGFL 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_ALLOCBT_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_ALLOCBT_AGFL_RESERVE; + blocks += 3; /* AGF, AGI btree root blocks */ + if (xfs_has_finobt(mp)) + blocks++; /* finobt root block */ + if (xfs_has_rmapbt(mp)) + blocks++; /* rmap root block */ + if (xfs_has_reflink(mp)) + 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; + struct xfs_perag *pag = cur->bc_ag.pag; + 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_agbext(pag, *bno, *len)) + 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", + pag->pag_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( + struct xfs_btree_cur *cnt_cur, /* cursor for by-size btree */ + struct xfs_btree_cur *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_levels[0].bp); + cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_levels[0].bp); + + 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_has_crc(mp)) + 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_has_crc(mp)) + 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_has_crc(mp)) + 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 +xfs_alloc_read_agfl( + struct xfs_perag *pag, + struct xfs_trans *tp, + struct xfs_buf **bpp) +{ + struct xfs_mount *mp = pag->pag_mount; + struct xfs_buf *bp; + int error; + + error = xfs_trans_read_buf( + mp, tp, mp->m_ddev_targp, + XFS_AG_DADDR(mp, pag->pag_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); + + 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->pag, 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->pag, XFS_BTNUM_BNO); + if (!acur->bnogt) + acur->bnogt = xfs_allocbt_init_cursor(args->mp, args->tp, + args->agbp, args->pag, 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->pag, args->tp, args->agbp, + &fbno, 0); + if (error) + goto error; + if (fbno == NULLAGBLOCK) + goto out; + + xfs_extent_busy_reuse(args->mp, args->pag, 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->pag, 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->pag, + 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->pag, + 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; + struct xfs_btree_cur *bno_cur;/* by block-number btree cursor */ + struct xfs_btree_cur *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->pag, 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->pag, 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_max(2)) + 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_levels[0].ptr = 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; + struct xfs_btree_cur *bno_cur; /* cursor for bno btree */ + struct xfs_btree_cur *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->pag, XFS_BTNUM_CNT); + bno_cur = NULL; + + /* + * Look for an entry >= maxlen+alignment-1 blocks. + */ + if ((error = xfs_alloc_lookup_ge(cnt_cur, 0, + args->maxlen + args->alignment - 1, &i))) + goto error0; + + /* + * If none 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->pag, 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; + struct xfs_perag *pag = agbp->b_pag; + + bno_cur = cnt_cur = NULL; + mp = tp->t_mountp; + + if (!xfs_rmap_should_skip_owner_update(oinfo)) { + error = xfs_rmap_free(tp, agbp, pag, 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, pag, 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, <bno, <len, &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, >bno, >len, &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, pag, 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_alloc_maxlevels. + */ +void +xfs_alloc_compute_maxlevels( + xfs_mount_t *mp) /* file system mount structure */ +{ + mp->m_alloc_maxlevels = xfs_btree_compute_maxlevels(mp->m_alloc_mnr, + (mp->m_sb.sb_agblocks + 1) / 2); + ASSERT(mp->m_alloc_maxlevels <= xfs_allocbt_maxlevels_ondisk()); +} + +/* + * 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_alloc_maxlevels > 0); + + /* space needed by-bno freespace btree */ + min_free = min_t(unsigned int, levels[XFS_BTNUM_BNOi] + 1, + mp->m_alloc_maxlevels); + /* space needed by-size freespace btree */ + min_free += min_t(unsigned int, levels[XFS_BTNUM_CNTi] + 1, + mp->m_alloc_maxlevels); + /* space needed reverse mapping used space btree */ + if (xfs_has_rmapbt(mp)) + 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_has_crc(mp)) + 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_free_extent_later() 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_extfree_item_cache != NULL); + ASSERT(oinfo != NULL); + + new = kmem_cache_zalloc(xfs_extfree_item_cache, + GFP_KERNEL | __GFP_NOFAIL); + new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno); + new->xefi_blockcount = 1; + new->xefi_owner = oinfo->oi_owner; + + trace_xfs_agfl_free_defer(mp, agno, 0, agbno, 1); + + xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_AGFL_FREE, &new->xefi_list); +} + +/* + * Add the extent to the list of extents to be free at transaction end. + * The list is maintained sorted (by block number). + */ +void +__xfs_free_extent_later( + struct xfs_trans *tp, + xfs_fsblock_t bno, + xfs_filblks_t len, + const struct xfs_owner_info *oinfo, + bool skip_discard) +{ + struct xfs_extent_free_item *new; /* new element */ +#ifdef DEBUG + struct xfs_mount *mp = tp->t_mountp; + xfs_agnumber_t agno; + xfs_agblock_t agbno; + + ASSERT(bno != NULLFSBLOCK); + ASSERT(len > 0); + ASSERT(len <= XFS_MAX_BMBT_EXTLEN); + ASSERT(!isnullstartblock(bno)); + agno = XFS_FSB_TO_AGNO(mp, bno); + agbno = XFS_FSB_TO_AGBNO(mp, bno); + ASSERT(agno < mp->m_sb.sb_agcount); + ASSERT(agbno < mp->m_sb.sb_agblocks); + ASSERT(len < mp->m_sb.sb_agblocks); + ASSERT(agbno + len <= mp->m_sb.sb_agblocks); +#endif + ASSERT(xfs_extfree_item_cache != NULL); + + new = kmem_cache_zalloc(xfs_extfree_item_cache, + GFP_KERNEL | __GFP_NOFAIL); + new->xefi_startblock = bno; + new->xefi_blockcount = (xfs_extlen_t)len; + if (skip_discard) + new->xefi_flags |= XFS_EFI_SKIP_DISCARD; + if (oinfo) { + ASSERT(oinfo->oi_offset == 0); + + if (oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK) + new->xefi_flags |= XFS_EFI_ATTR_FORK; + if (oinfo->oi_flags & XFS_OWNER_INFO_BMBT_BLOCK) + new->xefi_flags |= XFS_EFI_BMBT_BLOCK; + new->xefi_owner = oinfo->oi_owner; + } else { + new->xefi_owner = XFS_RMAP_OWN_NULL; + } + trace_xfs_bmap_free_defer(tp->t_mountp, + XFS_FSB_TO_AGNO(tp->t_mountp, bno), 0, + XFS_FSB_TO_AGBNO(tp->t_mountp, bno), len); + xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_FREE, &new->xefi_list); +} + +#ifdef DEBUG +/* + * Check if an AGF has a free extent record whose length is equal to + * args->minlen. + */ +STATIC int +xfs_exact_minlen_extent_available( + struct xfs_alloc_arg *args, + struct xfs_buf *agbp, + int *stat) +{ + struct xfs_btree_cur *cnt_cur; + xfs_agblock_t fbno; + xfs_extlen_t flen; + int error = 0; + + cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, agbp, + args->pag, XFS_BTNUM_CNT); + error = xfs_alloc_lookup_ge(cnt_cur, 0, args->minlen, stat); + if (error) + goto out; + + if (*stat == 0) { + error = -EFSCORRUPTED; + goto out; + } + + error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, stat); + if (error) + goto out; + + if (*stat == 1 && flen != args->minlen) + *stat = 0; + +out: + xfs_btree_del_cursor(cnt_cur, error); + + return error; +} +#endif + +/* + * 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(pag, tp, 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(pag, tp, 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; + +#ifdef DEBUG + if (args->alloc_minlen_only) { + int stat; + + error = xfs_exact_minlen_extent_available(args, agbp, &stat); + if (error || !stat) + goto out_agbp_relse; + } +#endif + /* + * 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(pag, 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(pag, tp, &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(pag, 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 +xfs_alloc_get_freelist( + struct xfs_perag *pag, + struct xfs_trans *tp, + struct xfs_buf *agbp, + xfs_agblock_t *bnop, + int btreeblk) +{ + struct xfs_agf *agf = agbp->b_addr; + struct xfs_buf *agflbp; + xfs_agblock_t bno; + __be32 *agfl_bno; + int error; + uint32_t logflags; + struct xfs_mount *mp = tp->t_mountp; + + /* + * Freelist is empty, give up. + */ + if (!agf->agf_flcount) { + *bnop = NULLAGBLOCK; + return 0; + } + /* + * Read the array of free blocks. + */ + error = xfs_alloc_read_agfl(pag, tp, &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; + + ASSERT(!pag->pagf_agflreset); + be32_add_cpu(&agf->agf_flcount, -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( + struct xfs_trans *tp, + struct xfs_buf *bp, + uint32_t fields) +{ + 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); +} + +/* + * Put the block on the freelist for the allocation group. + */ +int +xfs_alloc_put_freelist( + struct xfs_perag *pag, + struct xfs_trans *tp, + struct xfs_buf *agbp, + struct xfs_buf *agflbp, + xfs_agblock_t bno, + int btreeblk) +{ + struct xfs_mount *mp = tp->t_mountp; + struct xfs_agf *agf = agbp->b_addr; + __be32 *blockp; + int error; + uint32_t logflags; + __be32 *agfl_bno; + int startoff; + + if (!agflbp) { + error = xfs_alloc_read_agfl(pag, tp, &agflbp); + if (error) + return error; + } + + be32_add_cpu(&agf->agf_fllast, 1); + if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp)) + agf->agf_fllast = 0; + + ASSERT(!pag->pagf_agflreset); + be32_add_cpu(&agf->agf_flcount, 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_has_crc(mp)) { + 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]) > + mp->m_alloc_maxlevels || + be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) > + mp->m_alloc_maxlevels) + return __this_address; + + if (xfs_has_rmapbt(mp) && + (be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) < 1 || + be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > + mp->m_rmap_maxlevels)) + return __this_address; + + if (xfs_has_rmapbt(mp) && + 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_has_lazysbcount(mp) && + be32_to_cpu(agf->agf_btreeblks) > be32_to_cpu(agf->agf_length)) + return __this_address; + + if (xfs_has_reflink(mp) && + be32_to_cpu(agf->agf_refcount_blocks) > + be32_to_cpu(agf->agf_length)) + return __this_address; + + if (xfs_has_reflink(mp) && + (be32_to_cpu(agf->agf_refcount_level) < 1 || + be32_to_cpu(agf->agf_refcount_level) > mp->m_refc_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_has_crc(mp) && + !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_has_crc(mp)) + 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 +xfs_read_agf( + struct xfs_perag *pag, + struct xfs_trans *tp, + int flags, + struct xfs_buf **agfbpp) +{ + struct xfs_mount *mp = pag->pag_mount; + int error; + + trace_xfs_read_agf(pag->pag_mount, pag->pag_agno); + + error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, + XFS_AG_DADDR(mp, pag->pag_agno, XFS_AGF_DADDR(mp)), + XFS_FSS_TO_BB(mp, 1), flags, agfbpp, &xfs_agf_buf_ops); + if (error) + return error; + + xfs_buf_set_ref(*agfbpp, XFS_AGF_REF); + return 0; +} + +/* + * Read in the allocation group header (free/alloc section) and initialise the + * perag structure if necessary. If the caller provides @agfbpp, then return the + * locked buffer to the caller, otherwise free it. + */ +int +xfs_alloc_read_agf( + struct xfs_perag *pag, + struct xfs_trans *tp, + int flags, + struct xfs_buf **agfbpp) +{ + struct xfs_buf *agfbp; + struct xfs_agf *agf; + int error; + int allocbt_blks; + + trace_xfs_alloc_read_agf(pag->pag_mount, pag->pag_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)); + error = xfs_read_agf(pag, tp, + (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0, + &agfbp); + if (error) + return error; + + agf = agfbp->b_addr; + 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(pag->pag_mount, agf); + + /* + * Update the in-core allocbt counter. Filter out the rmapbt + * subset of the btreeblks counter because the rmapbt is managed + * by perag reservation. Subtract one for the rmapbt root block + * because the rmap counter includes it while the btreeblks + * counter only tracks non-root blocks. + */ + allocbt_blks = pag->pagf_btreeblks; + if (xfs_has_rmapbt(pag->pag_mount)) + allocbt_blks -= be32_to_cpu(agf->agf_rmap_blocks) - 1; + if (allocbt_blks > 0) + atomic64_add(allocbt_blks, + &pag->pag_mount->m_allocbt_blks); + } +#ifdef DEBUG + else if (!xfs_is_shutdown(pag->pag_mount)) { + 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 + if (agfbpp) + *agfbpp = agfbp; + else + xfs_trans_brelse(tp, agfbp); + 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) && + xfs_is_inode32(mp)) { + 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, + struct xfs_perag *pag, + 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 = pag->pag_agno; + args.pag = pag; + + /* + * 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; + + error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING); + if (error) + return error; + + *agbp = args.agbp; + return 0; +} + +/* + * 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; + struct xfs_perag *pag; + + ASSERT(len != 0); + ASSERT(type != XFS_AG_RESV_AGFL); + + if (XFS_TEST_ERROR(false, mp, + XFS_ERRTAG_FREE_EXTENT)) + return -EIO; + + pag = xfs_perag_get(mp, agno); + error = xfs_free_extent_fix_freelist(tp, pag, &agbp); + if (error) + goto err; + agf = agbp->b_addr; + + if (XFS_IS_CORRUPT(mp, agbno >= mp->m_sb.sb_agblocks)) { + error = -EFSCORRUPTED; + goto err_release; + } + + /* 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_release; + } + + error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, type); + if (error) + goto err_release; + + if (skip_discard) + busy_flags |= XFS_EXTENT_BUSY_SKIP_DISCARD; + xfs_extent_busy_insert(tp, pag, agbno, len, busy_flags); + xfs_perag_put(pag); + return 0; + +err_release: + xfs_trans_brelse(tp, agbp); +err: + xfs_perag_put(pag); + 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, + const 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, + const struct xfs_alloc_rec_incore *low_rec, + const 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; +} + +int __init +xfs_extfree_intent_init_cache(void) +{ + xfs_extfree_item_cache = kmem_cache_create("xfs_extfree_intent", + sizeof(struct xfs_extent_free_item), + 0, 0, NULL); + + return xfs_extfree_item_cache != NULL ? 0 : -ENOMEM; +} + +void +xfs_extfree_intent_destroy_cache(void) +{ + kmem_cache_destroy(xfs_extfree_item_cache); + xfs_extfree_item_cache = NULL; +} |