On Fri, Jan 15, 2010 at 01:53:15PM +0100, Peter Zijlstra wrote: > Well, I don't know enough about xfs (of filesystems in generic) to say > that with any certainty, but I can imagine inode writeback from the sync > that goes with umount to cause issues. > > If this inode reclaim is past all that and the filesystem is basically > RO, then I don't think so and this could be considered a false positive, > in which case we need an annotation for this. The issue is a bit more complicated. In the unmount case invalidate_inodes() is indeed called after the filesystem is effectively read-only for user origination operations. But there's a miriad of other invalidate_inodes() calls: - fs/block_dev.c:__invalidate_device() This gets called from block device codes for various kinds of invalidations. Doesn't make any sense at all to me, but hey.. - fs/ext2/super.c:ext2_remount() Appears like it's used to check for activate inodes during remount. Very fishy usage, and could just be replaced with a list walk without any I/O - fs/gfs2/glock.c:gfs2_gl_hash_clear() No idea. - fs/gfs2/ops_fstype.c:fill_super() Tries to kill all inodes in the fill_super error path, looks very fishy. - fs/ntfs/super.c:ntfs_fill_super() Failure case of fill_super again, does not look very useful.A - fs/smbfs/inode.c:smb_invalidate_inodes() Used when a connection goes bad. In short we can't generally rely on this only happening on a dead fs. But in the end we abuse iprune_sem to work around a ref counting problem. As long as we keep a reference to the superblock for each inode on the dispose list the superblock can't go away and there's no need for the lock at all. -- 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
