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UBIFS: TNC / GC race fixes

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- update GC sequence number if any nodes may have been moved
even if GC did not finish the LEB
- don't ignore error return when reading

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This commit is contained in:
Adrian Hunter 2008-09-12 12:27:47 +03:00 committed by Artem Bityutskiy
parent 0855f310df
commit 6dcfac4f13
2 changed files with 12 additions and 4 deletions
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14
fs/ubifs/gc.c
View file

@ -334,15 +334,15 @@ int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
err = move_nodes(c, sleb); err = move_nodes(c, sleb);
if (err) if (err)
goto out; goto out_inc_seq;
err = gc_sync_wbufs(c); err = gc_sync_wbufs(c);
if (err) if (err)
goto out; goto out_inc_seq;
err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0); err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);
if (err) if (err)
goto out; goto out_inc_seq;
/* Allow for races with TNC */ /* Allow for races with TNC */
c->gced_lnum = lnum; c->gced_lnum = lnum;
@ -369,6 +369,14 @@ int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
out: out:
ubifs_scan_destroy(sleb); ubifs_scan_destroy(sleb);
return err; return err;
out_inc_seq:
/* We may have moved at least some nodes so allow for races with TNC */
c->gced_lnum = lnum;
smp_wmb();
c->gc_seq += 1;
smp_wmb();
goto out;
} }
/** /**

2
fs/ubifs/tnc.c
View file

@ -1476,7 +1476,7 @@ int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
} }
err = fallible_read_node(c, key, &zbr, node); err = fallible_read_node(c, key, &zbr, node);
if (maybe_leb_gced(c, zbr.lnum, gc_seq1)) { if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
/* /*
* The node may have been GC'ed out from under us so try again * The node may have been GC'ed out from under us so try again
* while keeping the TNC mutex locked. * while keeping the TNC mutex locked.