GFS2: Add a rgrp bitmap full flag
During block allocation, it is useful to know if sections of disk
are full on a finer grained basis than a single resource group.
This can make a performance difference when resource groups have
larger numbers of bitmap blocks, since we no longer have to search
them all block by block in each individual bitmap.
The full flag is set on a per-bitmap basis when it has been
searched and found to have no free space. It is then skipped in
subsequent searches until the flag is reset. The resetting
occurs if we have to drop the glock on the resource group for any
reason, or if we deallocate some blocks within that resource
group and thus free up some space.
Signed-off-by: Steven Whitehouse <[email protected]>
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index fbacf09..23637b9 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -442,6 +442,7 @@
for (x = 0; x < length; x++) {
bi = rgd->rd_bits + x;
+ bi->bi_flags = 0;
/* small rgrp; bitmap stored completely in header block */
if (length == 1) {
bytes = bytes_left;
@@ -769,6 +770,8 @@
}
if (!(rgd->rd_flags & GFS2_RDF_UPTODATE)) {
+ for (x = 0; x < length; x++)
+ clear_bit(GBF_FULL, &rgd->rd_bits[x].bi_flags);
gfs2_rgrp_in(rgd, (rgd->rd_bits[0].bi_bh)->b_data);
rgd->rd_flags |= GFS2_RDF_UPTODATE;
}
@@ -897,6 +900,7 @@
continue;
if (sdp->sd_args.ar_discard)
gfs2_rgrp_send_discards(sdp, rgd->rd_data0, bi);
+ clear_bit(GBF_FULL, &bi->bi_flags);
memcpy(bi->bi_clone + bi->bi_offset,
bi->bi_bh->b_data + bi->bi_offset, bi->bi_len);
}
@@ -1309,30 +1313,37 @@
{
struct gfs2_bitmap *bi = NULL;
const u32 length = rgd->rd_length;
- u32 blk = 0;
+ u32 blk = BFITNOENT;
unsigned int buf, x;
const unsigned int elen = *n;
- const u8 *buffer;
+ const u8 *buffer = NULL;
*n = 0;
/* Find bitmap block that contains bits for goal block */
for (buf = 0; buf < length; buf++) {
bi = rgd->rd_bits + buf;
- if (goal < (bi->bi_start + bi->bi_len) * GFS2_NBBY)
- break;
+ /* Convert scope of "goal" from rgrp-wide to within found bit block */
+ if (goal < (bi->bi_start + bi->bi_len) * GFS2_NBBY) {
+ goal -= bi->bi_start * GFS2_NBBY;
+ goto do_search;
+ }
}
+ buf = 0;
+ goal = 0;
- gfs2_assert(rgd->rd_sbd, buf < length);
-
- /* Convert scope of "goal" from rgrp-wide to within found bit block */
- goal -= bi->bi_start * GFS2_NBBY;
-
+do_search:
/* Search (up to entire) bitmap in this rgrp for allocatable block.
"x <= length", instead of "x < length", because we typically start
the search in the middle of a bit block, but if we can't find an
allocatable block anywhere else, we want to be able wrap around and
search in the first part of our first-searched bit block. */
for (x = 0; x <= length; x++) {
+ bi = rgd->rd_bits + buf;
+
+ if (test_bit(GBF_FULL, &bi->bi_flags) &&
+ (old_state == GFS2_BLKST_FREE))
+ goto skip;
+
/* The GFS2_BLKST_UNLINKED state doesn't apply to the clone
bitmaps, so we must search the originals for that. */
buffer = bi->bi_bh->b_data + bi->bi_offset;
@@ -1343,33 +1354,39 @@
if (blk != BFITNOENT)
break;
+ if ((goal == 0) && (old_state == GFS2_BLKST_FREE))
+ set_bit(GBF_FULL, &bi->bi_flags);
+
/* Try next bitmap block (wrap back to rgrp header if at end) */
- buf = (buf + 1) % length;
- bi = rgd->rd_bits + buf;
+skip:
+ buf++;
+ buf %= length;
goal = 0;
}
- if (blk != BFITNOENT && old_state != new_state) {
- *n = 1;
- 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->bi_len, blk, new_state);
- goal = blk;
- while (*n < elen) {
- goal++;
- if (goal >= (bi->bi_len * GFS2_NBBY))
- break;
- if (gfs2_testbit(rgd, buffer, bi->bi_len, goal) !=
- GFS2_BLKST_FREE)
- break;
- gfs2_setbit(rgd, bi->bi_bh->b_data, bi->bi_clone,
- bi->bi_offset, bi->bi_len, goal,
- new_state);
- (*n)++;
- }
- }
+ if (blk == BFITNOENT)
+ return blk;
+ *n = 1;
+ if (old_state == new_state)
+ goto out;
- return (blk == BFITNOENT) ? blk : (bi->bi_start * GFS2_NBBY) + blk;
+ 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->bi_len, blk, new_state);
+ goal = blk;
+ while (*n < elen) {
+ goal++;
+ if (goal >= (bi->bi_len * GFS2_NBBY))
+ break;
+ if (gfs2_testbit(rgd, buffer, bi->bi_len, goal) !=
+ GFS2_BLKST_FREE)
+ break;
+ gfs2_setbit(rgd, bi->bi_bh->b_data, bi->bi_clone, bi->bi_offset,
+ bi->bi_len, goal, new_state);
+ (*n)++;
+ }
+out:
+ return (bi->bi_start * GFS2_NBBY) + blk;
}
/**
