Messages in this thread | | | Date | Fri, 16 May 2008 06:40:02 -0400 | From | Christoph Hellwig <> | Subject | Re: [PATCH take 2] UBIFS - new flash file system |
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General comment:
- not supporting a flash page size different from the system page size is a horrible thing for people trying to use the same storage on multiple systems. For a block based filesystem that alone would be enough reason not to merge it. For a flash filesystem I'm not entirely sure given that flash isn't moved between systems all that often.
VFS/VM interaction comments:
- splitting most of the mount code out to build.c is rather odd. Most filesystems have this in super.c - calling convention for mount_ubifs is nasty because it doesn't clean up it's own errors. You might think it's easier to do all that in ubifs_umount but beeing in the process of untangling that mess for xfs I'd recomment against it. Unless there's a very good reason for it functions should always clean up the resources they allocated in the error case. - ubifs_get_sb would benefit from splitting out a ubifs_fill_super routine that allocates a new sb when it's actually needed. - why do you do the commit_on_unmount in your own ->shutdown_super instead of the normal ->put_super? If there's a good reason this at least needs a big comment explaining why. - ubifs_lookup doesn't really need to use d_splice_alias unless you want to support nfs exporting - in ubifs_new_inode you inherit the inode flags from the parent. This probably wants splitting out in a helper that documents explicitly what flags are inherited and what not. Given that you store the general indoe flags settable by chattr in there it seems like a bad idea to inherit them by default. - the read dir implementation won't ever support nfs exporting due to having to keep per open file state. Nor would it support thing like checkpoint and restart. - just opencode you mmap routine, there's nothing helpful in generic_file_mmap if you set your own vm_ops. - ubifs_trunc should never be called on anything but a regular file, so the check for it seems superflous. Having it after the S_ISREG is rather odd too even if you want to have an assertation. - please implement the unlocked_ioctl file operation instead of the old ioctl operation that comes with the BKL locked.
Misc comments:
- ubifs_bg_thread shouldn't set a nice level, especially when it's the default one anyway. - the mainoop of ubifs_bg_thread looks a bit odd either, when you first to an interruotible sleep and then possible one while you still have TASK_RUNNING set. Also the need_bgt flag is not needed because the thrad is only woken up to perform it's action. In the end the main loop should look something like:
while (1) { if (kthread_should_stop()) break; if (try_to_freeze()) continue;
run_bg_commit(c);
set_current_state(TASK_INTERRUPTIBLE); schedule(); __set_current_state(TASK_RUNNING); }
Same comments on naming in the code:
- bgt is not very descriptive for your kernel thread. These are per defintion in the background, so just call them thread or <somethinginformative>_thread. In this case it would probably be commit_thread. - any chance you could spell out journal instead of jrn? jrn always sounds like joern with the wovel eaten by a mailer.. :)
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