Do not cluster with B_LOCKED buffers.
This is an odd one. This patch appears to fix a panic related to background bitmap writes (for FFS), though neither Kirk, Ian, or I can figure out how B_CLUSTEROK could possibly be set on a bitmap block to cause the clustering code to improperly cluster with a buffer undergoing a background write. In anycase, the clustering code is very fragile and this patch helps with that, as well as possibly fixing a bug Andre was having. Suggested by: Ian Dowse <iedowse@maths.tcd.ie> Testing by: Andre Albsmeier <andre.albsmeier@mchp.siemens.de>
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bcc740c453
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=71230
@ -399,15 +399,22 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp)
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tbp = getblk(vp, lbn + i, size, 0, 0);
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if ((tbp->b_flags & B_CACHE) ||
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/*
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* If the buffer is already fully valid or locked
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* (which could also mean that a background write is
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* in progress), or the buffer is not backed by VMIO,
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* stop.
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*/
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if ((tbp->b_flags & (B_CACHE|B_LOCKED)) ||
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(tbp->b_flags & B_VMIO) == 0) {
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bqrelse(tbp);
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break;
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}
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for (j = 0;j < tbp->b_npages; j++)
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for (j = 0;j < tbp->b_npages; j++) {
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if (tbp->b_pages[j]->valid)
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break;
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}
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if (j != tbp->b_npages) {
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bqrelse(tbp);
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@ -710,8 +717,13 @@ cluster_wbuild(vp, size, start_lbn, len)
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while (len > 0) {
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s = splbio();
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/*
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* If the buffer is not delayed-write (i.e. dirty), or it
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* is delayed-write but either locked or inval, it cannot
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* partake in teh clustered write.
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*/
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if (((tbp = gbincore(vp, start_lbn)) == NULL) ||
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((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) ||
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((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) ||
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BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
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++start_lbn;
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--len;
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@ -784,12 +796,16 @@ cluster_wbuild(vp, size, start_lbn, len)
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/*
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* If it IS in core, but has different
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* characteristics, don't cluster with it.
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* characteristics, or is locked (which
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* means it could be undergoing a background
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* I/O or be in a weird state), then don't
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* cluster with it.
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*/
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if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK |
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B_INVAL | B_DELWRI | B_NEEDCOMMIT))
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!= (B_DELWRI | B_CLUSTEROK |
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(bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) ||
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(tbp->b_flags & B_LOCKED) ||
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tbp->b_wcred != bp->b_wcred ||
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BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) {
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splx(s);
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