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Go Back   Linux Archive > Redhat > Cluster Development

 
 
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Old 09-26-2012, 08:25 AM
Steven Whitehouse
 
Default GFS2: Fix unclaimed_blocks() wrapping bug and clean up

When rgd->rd_free_clone is less than rgd->rd_reserved, the
unclaimed_blocks() calculation would wrap and produce
incorrect results. This patch checks for this condition
when this function is called from gfs2_mblk_search()

In addition, the use of this particular function in other
places in the code has been dropped by means of a general
clean up of gfs2_inplace_reserve(). This function is now
much easier to follow.

Also the setting of the rgd->rd_last_alloc field is corrected.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 87ee0b7..8869541 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1231,7 +1231,7 @@ static struct gfs2_blkreserv *rs_insert(struct gfs2_bitmap *bi,
BUG_ON(!ip->i_res);
BUG_ON(gfs2_rs_active(rs));
/* Figure out where to put new node */
- /*BUG_ON(!gfs2_glock_is_locked_by_me(rgd->rd_gl));*/
+
while (*newn) {
struct gfs2_blkreserv *cur =
rb_entry(*newn, struct gfs2_blkreserv, rs_node);
@@ -1276,17 +1276,16 @@ static u32 unclaimed_blocks(struct gfs2_rgrpd *rgd)
/**
* rg_mblk_search - find a group of multiple free blocks
* @rgd: the resource group descriptor
- * @rs: the block reservation
* @ip: pointer to the inode for which we're reserving blocks
+ * @requested: number of blocks required for this allocation
*
* This is very similar to rgblk_search, except we're looking for whole
* 64-bit words that represent a chunk of 32 free blocks. I'm only focusing
* on aligned dwords for speed's sake.
*
- * Returns: 0 if successful or BFITNOENT if there isn't enough free space
*/

-static int rg_mblk_search(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip, unsigned requested)
+static void rg_mblk_search(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip, unsigned requested)
{
struct gfs2_bitmap *bi = rgd->rd_bits;
const u32 length = rgd->rd_length;
@@ -1299,11 +1298,16 @@ static int rg_mblk_search(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip, unsigne
u32 best_rs_bytes, unclaimed;
int best_rs_blocks;

+ if ((rgd->rd_free_clone < rgd->rd_reserved) ||
+ (unclaimed_blocks(rgd) < max(requested, RGRP_RSRV_MINBLKS)))
+ return;
+
/* Find bitmap block that contains bits for goal block */
if (rgrp_contains_block(rgd, ip->i_goal))
goal = ip->i_goal - rgd->rd_data0;
else
goal = rgd->rd_last_alloc;
+
for (buf = 0; buf < length; buf++) {
bi = rgd->rd_bits + buf;
/* Convert scope of "goal" from rgrp-wide to within
@@ -1366,10 +1370,8 @@ do_search:
BUG_ON(blk >= bi->bi_len * GFS2_NBBY);
rs = rs_insert(bi, ip, blk,
rsv_bytes * GFS2_NBBY);
- if (IS_ERR(rs))
- return PTR_ERR(rs);
if (rs)
- return 0;
+ return;
}
ptr += ALIGN(search_bytes, sizeof(u64));
}
@@ -1380,35 +1382,6 @@ skip:
buf %= length;
goal = 0;
}
-
- return BFITNOENT;
-}
-
-/**
- * try_rgrp_fit - See if a given reservation will fit in a given RG
- * @rgd: the RG data
- * @ip: the inode
- *
- * If there's room for the requested blocks to be allocated from the RG:
- * This will try to get a multi-block reservation first, and if that doesn't
- * fit, it will take what it can.
- *
- * Returns: 1 on success (it fits), 0 on failure (it doesn't fit)
- */
-
-static int try_rgrp_fit(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip,
- unsigned requested)
-{
- if (rgd->rd_flags & (GFS2_RGF_NOALLOC | GFS2_RDF_ERROR))
- return 0;
- /* Look for a multi-block reservation. */
- if (unclaimed_blocks(rgd) >= RGRP_RSRV_MINBLKS &&
- rg_mblk_search(rgd, ip, requested) != BFITNOENT)
- return 1;
- if (unclaimed_blocks(rgd) >= requested)
- return 1;
-
- return 0;
}

/**
@@ -1678,6 +1651,19 @@ static void try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, u64 skip
return;
}

+static bool gfs2_select_rgrp(struct gfs2_rgrpd **pos, const struct gfs2_rgrpd *begin)
+{
+ struct gfs2_rgrpd *rgd = *pos;
+
+ rgd = gfs2_rgrpd_get_next(rgd);
+ if (rgd == NULL)
+ rgd = gfs2_rgrpd_get_next(NULL);
+ *pos = rgd;
+ if (rgd != begin) /* If we didn't wrap */
+ return true;
+ return false;
+}
+
/**
* gfs2_inplace_reserve - Reserve space in the filesystem
* @ip: the inode to reserve space for
@@ -1697,10 +1683,8 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)

if (sdp->sd_args.ar_rgrplvb)
flags |= GL_SKIP;
- if (gfs2_assert_warn(sdp, requested)) {
- error = -EINVAL;
- goto out;
- }
+ if (gfs2_assert_warn(sdp, requested))
+ return -EINVAL;
if (gfs2_rs_active(rs)) {
begin = rs->rs_rbm.rgd;
flags = 0; /* Yoda: Do or do not. There is no try */
@@ -1713,84 +1697,82 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)
return -EBADSLT;

while (loops < 3) {
- rg_locked = 0;
-
- if (gfs2_glock_is_locked_by_me(rs->rs_rbm.rgd->rd_gl)) {
- rg_locked = 1;
- error = 0;
- } else if (!loops && !gfs2_rs_active(rs) &&
- rs->rs_rbm.rgd->rd_rs_cnt > RGRP_RSRV_MAX_CONTENDERS) {
- /* If the rgrp already is maxed out for contenders,
- we can eliminate it as a "first pass" without even
- requesting the rgrp glock. */
- error = GLR_TRYFAILED;
- } else {
+ rg_locked = 1;
+
+ if (!gfs2_glock_is_locked_by_me(rs->rs_rbm.rgd->rd_gl)) {
+ rg_locked = 0;
error = gfs2_glock_nq_init(rs->rs_rbm.rgd->rd_gl,
LM_ST_EXCLUSIVE, flags,
&rs->rs_rgd_gh);
- if (!error && sdp->sd_args.ar_rgrplvb) {
+ if (error == GLR_TRYFAILED)
+ goto next_rgrp;
+ if (unlikely(error))
+ return error;
+ if (sdp->sd_args.ar_rgrplvb) {
error = update_rgrp_lvb(rs->rs_rbm.rgd);
- if (error) {
+ if (unlikely(error)) {
gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
return error;
}
}
}
- switch (error) {
- case 0:
- if (gfs2_rs_active(rs)) {
- if (unclaimed_blocks(rs->rs_rbm.rgd) +
- rs->rs_free >= requested) {
- ip->i_rgd = rs->rs_rbm.rgd;
- return 0;
- }
- /* We have a multi-block reservation, but the
- rgrp doesn't have enough free blocks to
- satisfy the request. Free the reservation
- and look for a suitable rgrp. */
- gfs2_rs_deltree(ip, rs);
- }
- if (try_rgrp_fit(rs->rs_rbm.rgd, ip, requested)) {
- if (sdp->sd_args.ar_rgrplvb)
- gfs2_rgrp_bh_get(rs->rs_rbm.rgd);
- ip->i_rgd = rs->rs_rbm.rgd;
- return 0;
- }
- if (rs->rs_rbm.rgd->rd_flags & GFS2_RDF_CHECK) {
- if (sdp->sd_args.ar_rgrplvb)
- gfs2_rgrp_bh_get(rs->rs_rbm.rgd);
- try_rgrp_unlink(rs->rs_rbm.rgd, &last_unlinked,
- ip->i_no_addr);
- }
- if (!rg_locked)
- gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
- /* fall through */
- case GLR_TRYFAILED:
- rs->rs_rbm.rgd = gfs2_rgrpd_get_next(rs->rs_rbm.rgd);
- rs->rs_rbm.rgd = rs->rs_rbm.rgd ? : begin; /* if NULL, wrap */
- if (rs->rs_rbm.rgd != begin) /* If we didn't wrap */
- break;

- flags &= ~LM_FLAG_TRY;
- loops++;
- /* Check that fs hasn't grown if writing to rindex */
- if (ip == GFS2_I(sdp->sd_rindex) &&
- !sdp->sd_rindex_uptodate) {
- error = gfs2_ri_update(ip);
- if (error)
- goto out;
- } else if (loops == 2)
- /* Flushing the log may release space */
- gfs2_log_flush(sdp, NULL);
- break;
- default:
- goto out;
+ /* Skip unuseable resource groups */
+ if (rs->rs_rbm.rgd->rd_flags & (GFS2_RGF_NOALLOC | GFS2_RDF_ERROR))
+ goto skip_rgrp;
+
+ if (sdp->sd_args.ar_rgrplvb)
+ gfs2_rgrp_bh_get(rs->rs_rbm.rgd);
+
+ /* Get a reservation if we don't already have one */
+ if (!gfs2_rs_active(rs))
+ rg_mblk_search(rs->rs_rbm.rgd, ip, requested);
+
+ /* Skip rgrps when we can't get a reservation on first pass */
+ if (!gfs2_rs_active(rs) && (loops < 1))
+ goto check_rgrp;
+
+ /* If rgrp has enough free space, use it */
+ if (rs->rs_rbm.rgd->rd_free_clone >= requested) {
+ ip->i_rgd = rs->rs_rbm.rgd;
+ return 0;
}
+
+ /* Drop reservation, if we couldn't use reserved rgrp */
+ if (gfs2_rs_active(rs))
+ gfs2_rs_deltree(ip, rs);
+check_rgrp:
+ /* Check for unlinked inodes which can be reclaimed */
+ if (rs->rs_rbm.rgd->rd_flags & GFS2_RDF_CHECK)
+ try_rgrp_unlink(rs->rs_rbm.rgd, &last_unlinked,
+ ip->i_no_addr);
+skip_rgrp:
+ /* Unlock rgrp if required */
+ if (!rg_locked)
+ gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
+next_rgrp:
+ /* Find the next rgrp, and continue looking */
+ if (gfs2_select_rgrp(&rs->rs_rbm.rgd, begin))
+ continue;
+
+ /* If we've scanned all the rgrps, but found no free blocks
+ * then this checks for some less likely conditions before
+ * trying again.
+ */
+ flags &= ~LM_FLAG_TRY;
+ loops++;
+ /* Check that fs hasn't grown if writing to rindex */
+ if (ip == GFS2_I(sdp->sd_rindex) && !sdp->sd_rindex_uptodate) {
+ error = gfs2_ri_update(ip);
+ if (error)
+ return error;
+ }
+ /* Flushing the log may release space */
+ if (loops == 2)
+ gfs2_log_flush(sdp, NULL);
}
- error = -ENOSPC;

-out:
- return error;
+ return -ENOSPC;
}

/**
@@ -2024,6 +2006,7 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,

gfs2_alloc_extent(&rbm, dinode, nblocks);
block = gfs2_rbm_to_block(&rbm);
+ rbm.rgd->rd_last_alloc = block - rbm.rgd->rd_data0;
if (gfs2_rs_active(ip->i_res))
gfs2_adjust_reservation(ip, &rbm, *nblocks);
ndata = *nblocks;
--
1.7.4
 

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