Hi, during my page_mkwrite() work, I've looked at who uses nobh_ versions of various functions in fs/buffer.c. It seems only ext2 and jfs use them. ext3 uses them only from writepage() (which means we needn't attach buffers to a page when it was written via mmap in writeback mode) and ext4 tries to use them but in fact it's nop because it always attaches buffers to the page earlier. So it's not really widely used, there's quite some code to support it (including one page flag), and it also slightly complicates my page_mkwrite() fixes. So I wanted to ask does somebody actually remember what it is good for? Buffer heads obviously consume some memory so was that the reason? OTOH we have to map the page whenever we write to it or send it to disk via writepage(). 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
