2013/2/4, Jan Kara <jack@xxxxxxx>: > On Sat 02-02-13 15:21:09, Namjae Jeon wrote: >> Hi. Jan. >> >> Sorry for interrupt. >> Have you taken this patch to your tree ? I can not find it.. >> or Is there any issue regarding this patch ? > I had it in my tree but not in the for_next branch. Did it now so you > should see the patch in tomorrow's linux-next. Okay, I see. Thanks Jan! > > Honza >> 2013/1/22, Namjae Jeon <linkinjeon@xxxxxxxxx>: >> > 2013/1/22, Jan Kara <jack@xxxxxxx>: >> >> On Tue 22-01-13 09:45:09, Namjae Jeon wrote: >> >>> 2013/1/21, Jan Kara <jack@xxxxxxx>: >> >>> > @@ -2222,6 +2219,8 @@ int udf_read_extent_cache(struct inode >> >>> > *inode, >> >>> > loff_t >> >>> > bcount, >> >>> > *lbcount = iinfo->cached_extent.lstart; >> >>> > memcpy(pos, &iinfo->cached_extent.epos, >> >>> > sizeof(struct extent_position)); >> >>> > + if (pos->bh) >> >>> > + get_bh(pos->bh); >> >>> > spin_unlock(&iinfo->i_extent_cache_lock); >> >>> > return 1; >> >>> > } else >> >>> > This is the most important - we should give buffer reference to >> >>> > pos->bh. >> >>> > Caller will eventually free it right? >> >>> This change is not required as we give buffer reference to pos->bh at >> >>> the time of cache update. >> >>> When we start reading a file, first we try to read the cache which >> >>> will lead to cache miss. >> >>> So, we would really access the pos->bh in udf_update_extent_cache for >> >>> the first time, and this is where the buffer reference is >> >>> incremented. >> >>> Calling get_bh at 2 places will eventually lead to mem leak. >> >>> Let me know your opinion. >> >> Yes, udf_update_extent_cache() gets its own reference to bh but that >> >> is >> >> dropped in udf_clear_extent_cache(). So I think >> >> udf_read_extent_cache() >> >> needs to get a reference to the caller (as the caller will eventually >> >> free >> >> the bh via brelse(epos.bh) e.g. in udf_extend_file(). Also I realized >> >> udf_update_extent_cache() needs to first clear the cache if it is >> >> valid. >> >> Otherwise it just overwrites bh pointer and reference is leaked. Is it >> >> clearer now? >> > Yes, you're right. Also, this patch looks good to me. >> >> >> >> I've also changed locking of udf_clear_extent_cache() so that >> >> i_extent_cache_lock is always taken for that function - it makes the >> >> locking rules obvious at the first sight. >> > Yes, right. it is needed. >> > When we test with this patch, working fine. >> > Thanks Jan! >> >> >> >> Attached is the patch I currently carry. >> >> >> >> Honza >> >> >> >> -- >> >> Jan Kara <jack@xxxxxxx> >> >> SUSE Labs, CR >> >> >> > > -- > Jan Kara <jack@xxxxxxx> > SUSE Labs, CR > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
