From 50adbcb4c4e6c94b3acaad2a5854b6ca57402115 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Mon, 22 Jun 2015 10:04:31 +1000 Subject: [PATCH] xfs: xfs_alloc_fix_freelist() can use incore perag structures At the moment, xfs_alloc_fix_freelist() uses a mix of per-ag based access and agf buffer based access to freelist and space usage information. However, once the AGF buffer is locked inside this function, it is guaranteed that both the in-memory and on-disk values are identical. xfs_alloc_fix_freelist() doesn't modify the values in the structures directly, so it is a read-only user of the infomration, and hence can use the per-ag structure exclusively for determining what it should do. This opens up an avenue for cleaning up a lot of duplicated logic whose only difference is the structure it gets the data from, and in doing so removes a lot of needless byte swapping overhead when fixing up the free list. Signed-off-by: Dave Chinner Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_alloc.c | 69 ++++++++++++++++++--------------------- fs/xfs/libxfs/xfs_alloc.h | 8 ++--- fs/xfs/libxfs/xfs_bmap.c | 3 +- fs/xfs/xfs_filestream.c | 3 +- 4 files changed, 37 insertions(+), 46 deletions(-) diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index 516162be1398..9b3e3681dfa9 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -1825,11 +1825,11 @@ xfs_alloc_compute_maxlevels( xfs_extlen_t xfs_alloc_longest_free_extent( struct xfs_mount *mp, - struct xfs_perag *pag) + struct xfs_perag *pag, + xfs_extlen_t need) { - xfs_extlen_t need, delta = 0; + xfs_extlen_t delta = 0; - need = XFS_MIN_FREELIST_PAG(pag, mp); if (need > pag->pagf_flcount) delta = need - pag->pagf_flcount; @@ -1848,10 +1848,8 @@ xfs_alloc_fix_freelist( int flags) /* XFS_ALLOC_FLAG_... */ { xfs_buf_t *agbp; /* agf buffer pointer */ - xfs_agf_t *agf; /* a.g. freespace structure pointer */ xfs_buf_t *agflbp;/* agfl buffer pointer */ xfs_agblock_t bno; /* freelist block */ - xfs_extlen_t delta; /* new blocks needed in freelist */ int error; /* error result code */ xfs_extlen_t longest;/* longest extent in allocation group */ xfs_mount_t *mp; /* file system mount point structure */ @@ -1895,7 +1893,7 @@ xfs_alloc_fix_freelist( * total blocks, reject it. */ need = XFS_MIN_FREELIST_PAG(pag, mp); - longest = xfs_alloc_longest_free_extent(mp, pag); + longest = xfs_alloc_longest_free_extent(mp, pag, need); if ((args->minlen + args->alignment + args->minalignslop - 1) > longest || ((int)(pag->pagf_freeblks + pag->pagf_flcount - @@ -1922,25 +1920,16 @@ xfs_alloc_fix_freelist( return 0; } } - /* - * Figure out how many blocks we should have in the freelist. - */ - agf = XFS_BUF_TO_AGF(agbp); - need = XFS_MIN_FREELIST(agf, mp); - /* - * If there isn't enough total or single-extent, reject it. - */ + + + /* If there isn't enough total space or single-extent, reject it. */ + need = XFS_MIN_FREELIST_PAG(pag, mp); if (!(flags & XFS_ALLOC_FLAG_FREEING)) { - delta = need > be32_to_cpu(agf->agf_flcount) ? - (need - be32_to_cpu(agf->agf_flcount)) : 0; - longest = be32_to_cpu(agf->agf_longest); - longest = (longest > delta) ? (longest - delta) : - (be32_to_cpu(agf->agf_flcount) > 0 || longest > 0); + longest = xfs_alloc_longest_free_extent(mp, pag, need); if ((args->minlen + args->alignment + args->minalignslop - 1) > longest || - ((int)(be32_to_cpu(agf->agf_freeblks) + - be32_to_cpu(agf->agf_flcount) - need - args->total) < - (int)args->minleft)) { + ((int)(pag->pagf_freeblks + pag->pagf_flcount - + need - args->total) < (int)args->minleft)) { xfs_trans_brelse(tp, agbp); args->agbp = NULL; return 0; @@ -1948,21 +1937,25 @@ xfs_alloc_fix_freelist( } /* * Make the freelist shorter if it's too long. + * + * 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? */ - while (be32_to_cpu(agf->agf_flcount) > need) { - xfs_buf_t *bp; + while (pag->pagf_flcount > need) { + struct xfs_buf *bp; error = xfs_alloc_get_freelist(tp, agbp, &bno, 0); if (error) return error; - if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1))) + error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1); + if (error) return error; bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0); xfs_trans_binval(tp, bp); } - /* - * Initialize the args structure. - */ + memset(&targs, 0, sizeof(targs)); targs.tp = tp; targs.mp = mp; @@ -1971,18 +1964,18 @@ xfs_alloc_fix_freelist( targs.alignment = targs.minlen = targs.prod = targs.isfl = 1; targs.type = XFS_ALLOCTYPE_THIS_AG; targs.pag = pag; - if ((error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp))) + error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp); + if (error) return error; - /* - * Make the freelist longer if it's too short. - */ - while (be32_to_cpu(agf->agf_flcount) < need) { + + /* Make the freelist longer if it's too short. */ + while (pag->pagf_flcount < need) { targs.agbno = 0; - targs.maxlen = need - be32_to_cpu(agf->agf_flcount); - /* - * Allocate as many blocks as possible at once. - */ - if ((error = xfs_alloc_ag_vextent(&targs))) { + targs.maxlen = need - pag->pagf_flcount; + + /* Allocate as many blocks as possible at once. */ + error = xfs_alloc_ag_vextent(&targs); + if (error) { xfs_trans_brelse(tp, agflbp); return error; } diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h index d1b4b6a5c894..8815fc30f83d 100644 --- a/fs/xfs/libxfs/xfs_alloc.h +++ b/fs/xfs/libxfs/xfs_alloc.h @@ -128,12 +128,8 @@ typedef struct xfs_alloc_arg { #define XFS_ALLOC_USERDATA 1 /* allocation is for user data*/ #define XFS_ALLOC_INITIAL_USER_DATA 2 /* special case start of file */ -/* - * Find the length of the longest extent in an AG. - */ -xfs_extlen_t -xfs_alloc_longest_free_extent(struct xfs_mount *mp, - struct xfs_perag *pag); +xfs_extlen_t xfs_alloc_longest_free_extent(struct xfs_mount *mp, + struct xfs_perag *pag, xfs_extlen_t need); /* * Compute and fill in value of m_ag_maxlevels. diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index aeffeaaac0ec..1ad4f1a62ce0 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -3507,7 +3507,8 @@ xfs_bmap_longest_free_extent( } } - longest = xfs_alloc_longest_free_extent(mp, pag); + longest = xfs_alloc_longest_free_extent(mp, pag, + XFS_MIN_FREELIST_PAG(pag, mp)); if (*blen < longest) *blen = longest; diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c index da82f1cb4b9b..9ac5eaad47bc 100644 --- a/fs/xfs/xfs_filestream.c +++ b/fs/xfs/xfs_filestream.c @@ -196,7 +196,8 @@ xfs_filestream_pick_ag( goto next_ag; } - longest = xfs_alloc_longest_free_extent(mp, pag); + longest = xfs_alloc_longest_free_extent(mp, pag, + XFS_MIN_FREELIST_PAG(pag, mp)); if (((minlen && longest >= minlen) || (!minlen && pag->pagf_freeblks >= minfree)) && (!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) || -- 2.39.5