On Sep 20, 2007 18:17 +0200, Jan Kara wrote: > > when converting ext4 directories to pagecache I just came over > > Takashi's patch preventing overflowing of rec_len. Looking over the > > patch - can't we do it more elegantly by using say 0xffff instead of 64K > > and perform conversion (using some helper) at the moment we read / store > > rec_len? That would be IMHO more transparent than current approach (at > > least it took me some time to understand what's going on with the > > current patch when I was looking at the code)... > > Attached is a patch that does this for ext4. If you like this > approach, I can cook up a similar patch for ext2 / ext3. Yes, I think this is much cleaner to avoid all the conditionals in the code. > With 64KB blocksize, a directory entry can have size 64KB which does not fit > into 16 bits we have for entry lenght. So we store 0xffff instead and convert > value when read from / written to disk. The patch also converts some places > to use ext4_next_entry() when we are changing them anyway. > > const char * error_msg = NULL; > - const int rlen = le16_to_cpu(de->rec_len); > + const int rlen = ext4_get_rec_len(le16_to_cpu(de->rec_len)); Maybe we should wrap the le16_to_cpu() into ext4_get_rec_len() itself, making the parameter just be "__le16 rec_len"? We appear to have le16_to_cpu() at every callsite. Likewise for ext4_store_rec_len() it should do the cpu_to_le16() internally and return an __le16. It should maybe be called ext4_set_rec_len() to be a more natural pairing? This also needs a patch for e2fsprogs, while I'm not sure the old patch did (has anyone ever checked this?) We could still consider making EXT4_DIR_MAX_REC_LEN as in Takashi's patch, but keep the cleanups here. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
