On Tue 06-09-11 11:44:45, Eric Sandeen wrote: > On 9/6/11 11:37 AM, Christian Kujau wrote: > > On Tue, 6 Sep 2011 at 11:17, Eric Sandeen wrote: > >> It's probably not a bug or flaw; orphan inodes can occur for legitimate > >> reasons (fs goes down while someone is holding open an unlinked file), > > > > The filesystem is being constantly accessed by an application, holding at > > least one file open (readonly). And then there is this mechanism trying to > > remount the filesystem rw and then ro again every day. I guess this equals > > the scenario of "fs goes down (remount!) while someone is holding open a > > file"? > > well, no - "goes down" means "crashed or lost power" > > >> Did you happen to also get a message like this on the original mount? > >> ext4_msg(sb, KERN_ERR, "write access " > >> "unavailable, skipping orphan cleanup"); > > > > I think I've seen this message before, but I'm nore sure where and it's > > not in the logs of this particular system. > > > >> See also commit: > >> > >> commit ead6596b9e776ac32d82f7d1931d7638e6d4a7bd > >> Author: Eric Sandeen <sandeen@xxxxxxxxxx> > >> Date: Sat Feb 10 01:46:08 2007 -0800 > >> > >> [PATCH] ext4: refuse ro to rw remount of fs with orphan inodes > > > > Yes, I've seen this commit when I was searching where this message came > > from. And I think I understand now why this is happening, but > > still...if I may ask: can't this be handled more elegantly? Do other > > filesystems have the same problem? > > well, as the commit said, it'd be nice to handle it in remount, yes... :( > > > Right now the procedure is to pause the application, stop the nfs exports, > > unmount, fsck, mount, start nfs exports and resume the application. And > > every few days/weeks this has to be repeated, "just because" these daily > > remounts occur (which are the main reason for this, I suppose). > > well, seems like you need to get to the root cause of the unprocessed > orphan inodes. > > I don't yet have my post-vacation thinking cap back on... does cycling > rw/ro/rw/ro with open & unlinked files cause an orphan inode situation? There's race where VFS remount code can race with unlink and result will be unlinked file in orphan list on read-only filesystem. Christian seems to be hitting this race. Miklos Szeredi has patches (http://lkml.indiana.edu/hypermail/linux/kernel/1108.3/00169.html) to mostly close this hole but they're waiting for Al to find time to look at them / merge them AFAIK. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- 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
