From: Li Chen <chenl311@chinatelecom.cn>
Segment info indexing also used sizeof(struct) instead of the
4K metadata stride, so info_index could point between slots and
subsequent writes would advance incorrectly. Derive info_index
from the pointer returned by the segment meta search using
PCACHE_SEG_INFO_SIZE and advance to the next slot for future
updates.
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
---
drivers/md/dm-pcache/cache_segment.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-pcache/cache_segment.c b/drivers/md/dm-pcache/cache_segment.c
index f0b58980806e..0b4bb08011ce 100644
--- a/drivers/md/dm-pcache/cache_segment.c
+++ b/drivers/md/dm-pcache/cache_segment.c
@@ -56,7 +56,11 @@ static int cache_seg_info_load(struct pcache_cache_segment *cache_seg)
ret = -EIO;
goto out;
}
- cache_seg->info_index = cache_seg_info_addr - cache_seg_info_addr_base;
+
+ cache_seg->info_index =
+ ((char *)cache_seg_info_addr - (char *)cache_seg_info_addr_base) /
+ PCACHE_SEG_INFO_SIZE;
+ cache_seg->info_index = (cache_seg->info_index + 1) % PCACHE_META_INDEX_MAX;
out:
mutex_unlock(&cache_seg->info_lock);
--
2.51.0在 12/2/2025 8:11 PM, Li Chen 写道: > From: Li Chen <chenl311@chinatelecom.cn> > > Segment info indexing also used sizeof(struct) instead of the > 4K metadata stride, so info_index could point between slots and > subsequent writes would advance incorrectly. Derive info_index > from the pointer returned by the segment meta search using > PCACHE_SEG_INFO_SIZE and advance to the next slot for future > updates. > > Signed-off-by: Li Chen <chenl311@chinatelecom.cn> > --- > drivers/md/dm-pcache/cache_segment.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/md/dm-pcache/cache_segment.c b/drivers/md/dm-pcache/cache_segment.c > index f0b58980806e..0b4bb08011ce 100644 > --- a/drivers/md/dm-pcache/cache_segment.c > +++ b/drivers/md/dm-pcache/cache_segment.c > @@ -56,7 +56,11 @@ static int cache_seg_info_load(struct pcache_cache_segment *cache_seg) > ret = -EIO; > goto out; > } > - cache_seg->info_index = cache_seg_info_addr - cache_seg_info_addr_base; > + > + cache_seg->info_index = > + ((char *)cache_seg_info_addr - (char *)cache_seg_info_addr_base) / > + PCACHE_SEG_INFO_SIZE; > + cache_seg->info_index = (cache_seg->info_index + 1) % PCACHE_META_INDEX_MAX; Don't advance info_index at init stage. > out: > mutex_unlock(&cache_seg->info_lock); >
在 12/3/2025 1:57 PM, Dongsheng Yang 写道: > > 在 12/2/2025 8:11 PM, Li Chen 写道: >> From: Li Chen <chenl311@chinatelecom.cn> >> >> Segment info indexing also used sizeof(struct) instead of the >> 4K metadata stride, so info_index could point between slots and >> subsequent writes would advance incorrectly. Derive info_index >> from the pointer returned by the segment meta search using >> PCACHE_SEG_INFO_SIZE and advance to the next slot for future >> updates. >> >> Signed-off-by: Li Chen <chenl311@chinatelecom.cn> >> --- >> drivers/md/dm-pcache/cache_segment.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/md/dm-pcache/cache_segment.c >> b/drivers/md/dm-pcache/cache_segment.c >> index f0b58980806e..0b4bb08011ce 100644 >> --- a/drivers/md/dm-pcache/cache_segment.c >> +++ b/drivers/md/dm-pcache/cache_segment.c >> @@ -56,7 +56,11 @@ static int cache_seg_info_load(struct >> pcache_cache_segment *cache_seg) >> ret = -EIO; >> goto out; >> } >> - cache_seg->info_index = cache_seg_info_addr - >> cache_seg_info_addr_base; >> + >> + cache_seg->info_index = >> + ((char *)cache_seg_info_addr - (char >> *)cache_seg_info_addr_base) / >> + PCACHE_SEG_INFO_SIZE; >> + cache_seg->info_index = (cache_seg->info_index + 1) % >> PCACHE_META_INDEX_MAX; > > > Don't advance info_index at init stage. ignore this incorrect comment, info_index means next slot, we need to advance it here. > >> out: >> mutex_unlock(&cache_seg->info_lock); >
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