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 ? Thanks! 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 >> > -- 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
