This enlarges the region that a garbage collection lock protects so
that indivisible steps of garbage collection do not interleave.
Target segments are selected outside the critical section, so this
also reexamines the selected segments after having acquired the lock.
This makes gc safe even if two or more cleaner daemons are
accidentally invoked and they run in parallel.
Reported-by: dexen deVries <dexen.devries@xxxxxxxxx>
Reported-by: Ivan Telichko <itelichko@xxxxxxxxx>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
---
sbin/cleanerd/cleanerd.c | 34 +++++++++++++++++++++++++---------
1 files changed, 25 insertions(+), 9 deletions(-)
diff --git a/sbin/cleanerd/cleanerd.c b/sbin/cleanerd/cleanerd.c
index b0a77fe..63c334e 100644
--- a/sbin/cleanerd/cleanerd.c
+++ b/sbin/cleanerd/cleanerd.c
@@ -243,6 +243,12 @@ static int nilfs_comp_segimp(const void *elem1, const void *elem2)
return (segimp1->si_segnum < segimp2->si_segnum) ? -1 : 1;
}
+static int nilfs_suinfo_reclaimable(const struct nilfs_suinfo *si)
+{
+ return nilfs_suinfo_dirty(si) &&
+ !nilfs_suinfo_active(si) && !nilfs_suinfo_error(si);
+}
+
#define NILFS_CLEANERD_NSUINFO 512
#define NILFS_CLEANERD_NULLTIME (~(__u64)0)
@@ -302,9 +308,7 @@ nilfs_cleanerd_select_segments(struct nilfs_cleanerd *cleanerd,
goto out;
}
for (i = 0; i < n; i++) {
- if (nilfs_suinfo_dirty(&si[i]) &&
- !nilfs_suinfo_active(&si[i]) &&
- !nilfs_suinfo_error(&si[i]) &&
+ if (nilfs_suinfo_reclaimable(&si[i]) &&
((imp = (*config->cf_selection_policy.p_importance)(&si[i])) < thr)) {
if (si[i].sui_lastmod < oldest)
oldest = si[i].sui_lastmod;
@@ -549,6 +553,18 @@ static ssize_t nilfs_cleanerd_acc_blocks(struct nilfs_cleanerd *cleanerd,
while (i < n) {
if (nilfs_get_suinfo(nilfs, segnums[i], &si, 1) < 0)
return -1;
+
+ if (!nilfs_suinfo_reclaimable(&si)) {
+ /*
+ * Recheck status of the segment and drop it
+ * if not reclaimable. This prevents the
+ * target segments from being cleaned twice or
+ * more by duplicate cleaner daemons.
+ */
+ n = nilfs_deselect_segment(segnums, n, i);
+ continue;
+ }
+
if (nilfs_get_segment(nilfs, segnums[i], &segment) < 0)
return -1;
@@ -945,20 +961,20 @@ static ssize_t nilfs_cleanerd_clean_segments(struct nilfs_cleanerd *cleanerd,
vblocknrv == NULL)
goto out_vec;
+ ret = nilfs_lock_cleaner(cleanerd->c_nilfs);
+ if (ret < 0)
+ goto out_vec;
+
n = nilfs_cleanerd_acc_blocks(cleanerd, sustat, segnums, nsegs,
vdescv, bdescv);
if (n <= 0) {
ret = n;
- goto out_vec;
+ goto out_lock;
}
ret = nilfs_cleanerd_get_vdesc(cleanerd, vdescv);
if (ret < 0)
- goto out_vec;
-
- ret = nilfs_lock_cleaner(cleanerd->c_nilfs);
- if (ret < 0)
- goto out_vec;
+ goto out_lock;
ret = nilfs_cleanerd_update_prottime(cleanerd, prottime);
if (ret < 0)
--
1.7.3.5
--
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