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    Subject[PATCH 12/16] GFS2: split function rgblk_search
    Date
    From: Bob Peterson <rpeterso@redhat.com>

    This patch splits function rgblk_search into a function that finds
    blocks to allocate (rgblk_search) and a function that assigns those
    blocks (gfs2_alloc_extent).

    Signed-off-by: Bob Peterson <rpeterso@redhat.com>
    Signed-off-by: Steven Whitehouse <swhiteho@rehat.com>

    diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
    index f1d1960..6b6cc09 100644
    --- a/fs/gfs2/rgrp.c
    +++ b/fs/gfs2/rgrp.c
    @@ -65,8 +65,8 @@ static const char valid_change[16] = {
    };

    static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,
    - unsigned char old_state, bool dinode,
    - unsigned int *ndata);
    + unsigned char old_state, bool dinode,
    + struct gfs2_bitmap **rbi);

    /**
    * gfs2_setbit - Set a bit in the bitmaps
    @@ -899,6 +899,11 @@ static int try_rgrp_fit(const struct gfs2_rgrpd *rgd, const struct gfs2_inode *i
    return 0;
    }

    +static inline u32 gfs2_bi2rgd_blk(struct gfs2_bitmap *bi, u32 blk)
    +{
    + return (bi->bi_start * GFS2_NBBY) + blk;
    +}
    +
    /**
    * try_rgrp_unlink - Look for any unlinked, allocated, but unused inodes
    * @rgd: The rgrp
    @@ -912,19 +917,20 @@ static void try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, u64 skip
    u32 goal = 0, block;
    u64 no_addr;
    struct gfs2_sbd *sdp = rgd->rd_sbd;
    - unsigned int n;
    struct gfs2_glock *gl;
    struct gfs2_inode *ip;
    int error;
    int found = 0;
    + struct gfs2_bitmap *bi;

    while (goal < rgd->rd_data) {
    down_write(&sdp->sd_log_flush_lock);
    - n = 1;
    - block = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED, 0, &n);
    + block = rgblk_search(rgd, goal, GFS2_BLKST_UNLINKED, 0, &bi);
    up_write(&sdp->sd_log_flush_lock);
    if (block == BFITNOENT)
    break;
    +
    + block = gfs2_bi2rgd_blk(bi, block);
    /* rgblk_search can return a block < goal, so we need to
    keep it marching forward. */
    no_addr = block + rgd->rd_data0;
    @@ -1109,38 +1115,35 @@ static unsigned char gfs2_get_block_type(struct gfs2_rgrpd *rgd, u64 block)
    }

    /**
    - * rgblk_search - find a block in @old_state, change allocation
    - * state to @new_state
    + * rgblk_search - find a block in @old_state
    * @rgd: the resource group descriptor
    * @goal: the goal block within the RG (start here to search for avail block)
    * @old_state: GFS2_BLKST_XXX the before-allocation state to find
    * @dinode: TRUE if the first block we allocate is for a dinode
    - * @n: The extent length
    + * @rbi: address of the pointer to the bitmap containing the block found
    *
    * Walk rgrp's bitmap to find bits that represent a block in @old_state.
    - * Add the found bitmap buffer to the transaction.
    - * Set the found bits to @new_state to change block's allocation state.
    *
    * This function never fails, because we wouldn't call it unless we
    * know (from reservation results, etc.) that a block is available.
    *
    - * Scope of @goal and returned block is just within rgrp, not the whole
    - * filesystem.
    + * Scope of @goal is just within rgrp, not the whole filesystem.
    + * Scope of @returned block is just within bitmap, not the whole filesystem.
    *
    - * Returns: the block number allocated
    + * Returns: the block number found relative to the bitmap rbi
    */

    static u32 rgblk_search(struct gfs2_rgrpd *rgd, u32 goal,
    - unsigned char old_state, bool dinode, unsigned int *n)
    + unsigned char old_state, bool dinode,
    + struct gfs2_bitmap **rbi)
    {
    struct gfs2_bitmap *bi = NULL;
    const u32 length = rgd->rd_length;
    u32 blk = BFITNOENT;
    unsigned int buf, x;
    - const unsigned int elen = *n;
    const u8 *buffer = NULL;

    - *n = 0;
    + *rbi = NULL;
    /* Find bitmap block that contains bits for goal block */
    for (buf = 0; buf < length; buf++) {
    bi = rgd->rd_bits + buf;
    @@ -1187,12 +1190,32 @@ skip:
    goal = 0;
    }

    - if (blk == BFITNOENT)
    - return blk;
    + if (blk != BFITNOENT)
    + *rbi = bi;

    - if (old_state == GFS2_BLKST_UNLINKED)
    - goto out;
    + return blk;
    +}

    +/**
    + * gfs2_alloc_extent - allocate an extent from a given bitmap
    + * @rgd: the resource group descriptor
    + * @bi: the bitmap within the rgrp
    + * @blk: the block within the bitmap
    + * @dinode: TRUE if the first block we allocate is for a dinode
    + * @n: The extent length
    + *
    + * Add the found bitmap buffer to the transaction.
    + * Set the found bits to @new_state to change block's allocation state.
    + * Returns: starting block number of the extent (fs scope)
    + */
    +static u64 gfs2_alloc_extent(struct gfs2_rgrpd *rgd, struct gfs2_bitmap *bi,
    + u32 blk, bool dinode, unsigned int *n)
    +{
    + const unsigned int elen = *n;
    + u32 goal;
    + const u8 *buffer = NULL;
    +
    + buffer = bi->bi_bh->b_data + bi->bi_offset;
    gfs2_trans_add_bh(rgd->rd_gl, bi->bi_bh, 1);
    gfs2_setbit(rgd, bi->bi_bh->b_data, bi->bi_clone, bi->bi_offset,
    bi, blk, dinode ? GFS2_BLKST_DINODE : GFS2_BLKST_USED);
    @@ -1210,8 +1233,9 @@ skip:
    bi, goal, GFS2_BLKST_USED);
    (*n)++;
    }
    -out:
    - return (bi->bi_start * GFS2_NBBY) + blk;
    + blk = gfs2_bi2rgd_blk(bi, blk);
    + rgd->rd_last_alloc = blk;
    + return rgd->rd_data0 + blk;
    }

    /**
    @@ -1319,6 +1343,7 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *ndata,
    u32 goal, extlen, blk; /* block, within the rgrp scope */
    u64 block; /* block, within the file system scope */
    int error;
    + struct gfs2_bitmap *bi;

    /* Only happens if there is a bug in gfs2, return something distinctive
    * to ensure that it is noticed.
    @@ -1333,14 +1358,15 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *ndata,
    else
    goal = rgd->rd_last_alloc;

    - blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, dinode, ndata);
    + blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, dinode, &bi);

    + *ndata = 0;
    /* Since all blocks are reserved in advance, this shouldn't happen */
    if (blk == BFITNOENT)
    goto rgrp_error;

    - rgd->rd_last_alloc = blk;
    - block = rgd->rd_data0 + blk;
    + block = gfs2_alloc_extent(rgd, bi, blk, dinode, ndata);
    +
    if (!dinode) {
    ip->i_goal = block + *ndata - 1;
    error = gfs2_meta_inode_buffer(ip, &dibh);
    --
    1.7.4


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