From 9e07f2cb3d7a93f4b1b18fc6e4dd6911dcba2442 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Wed, 2 Oct 2013 14:42:45 +0100 Subject: [PATCH] GFS2: Speed up starting point selection for block allocation When setting the starting point for block allocation, there were calls to both gfs2_rbm_to_block() and gfs2_rbm_from_block() in the common case of there being an active reservation. The gfs2_rbm_from_block() function can be quite slow, and since the two conversions were effectively a no-op, it makes sense to avoid them entirely in this case. There is no functional change here, but the code should be a bit more efficient after this patch. Signed-off-by: Steven Whitehouse --- fs/gfs2/rgrp.c | 41 +++++++++++++++++++++++++++++++---------- 1 file changed, 31 insertions(+), 10 deletions(-) diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 4f0984a..4d83abd 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -2134,6 +2134,35 @@ out: } /** + * gfs2_set_alloc_start - Set starting point for block allocation + * @rbm: The rbm which will be set to the required location + * @ip: The gfs2 inode + * @dinode: Flag to say if allocation includes a new inode + * + * This sets the starting point from the reservation if one is active + * otherwise it falls back to guessing a start point based on the + * inode's goal block or the last allocation point in the rgrp. + */ + +static void gfs2_set_alloc_start(struct gfs2_rbm *rbm, + const struct gfs2_inode *ip, bool dinode) +{ + u64 goal; + + if (gfs2_rs_active(ip->i_res)) { + *rbm = ip->i_res->rs_rbm; + return; + } + + if (!dinode && rgrp_contains_block(rbm->rgd, ip->i_goal)) + goal = ip->i_goal; + else + goal = rbm->rgd->rd_last_alloc + rbm->rgd->rd_data0; + + gfs2_rbm_from_block(rbm, goal); +} + +/** * gfs2_alloc_blocks - Allocate one or more blocks of data and/or a dinode * @ip: the inode to allocate the block for * @bn: Used to return the starting block number @@ -2151,22 +2180,14 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks, struct buffer_head *dibh; struct gfs2_rbm rbm = { .rgd = ip->i_rgd, }; unsigned int ndata; - u64 goal; u64 block; /* block, within the file system scope */ int error; - if (gfs2_rs_active(ip->i_res)) - goal = gfs2_rbm_to_block(&ip->i_res->rs_rbm); - else if (!dinode && rgrp_contains_block(rbm.rgd, ip->i_goal)) - goal = ip->i_goal; - else - goal = rbm.rgd->rd_last_alloc + rbm.rgd->rd_data0; - - gfs2_rbm_from_block(&rbm, goal); + gfs2_set_alloc_start(&rbm, ip, dinode); error = gfs2_rbm_find(&rbm, GFS2_BLKST_FREE, 0, ip, false); if (error == -ENOSPC) { - gfs2_rbm_from_block(&rbm, goal); + gfs2_set_alloc_start(&rbm, ip, dinode); error = gfs2_rbm_find(&rbm, GFS2_BLKST_FREE, 0, NULL, false); } -- 2.7.4