Messages in this thread | | | Date | Wed, 2 Jul 2008 20:42:50 +0100 | From | Al Viro <> | Subject | Re: [patch] vfs: fix lookup on deleted directory |
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On Wed, Jul 02, 2008 at 09:30:15PM +0200, Miklos Szeredi wrote:
> Lookup can install a child dentry for a deleted directory. This keeps > the directory dentry alive, and the inode pinned in the cache and on > disk, even after all external references have gone away. > > This isn't a big problem normally, since memory pressure or umount > will clear out the directory dentry and its children, releasing the > inode. But for UBIFS this causes problems because its orphan area can > overflow. > > Fix this by returning ENOENT for all lookups on a S_DEAD directory > before creating a child dentry.
I wonder if it would be better to do that in a slightly different way: if ->lookup() returns negative dentry, check if parent is dead and drop the sucker if it is. OTOH, "no ->lookup() will be ever called for dead ones" seems to be a nice property and we are on sufficiently slow path to not worry about the cost of check-and-branch-not-taken, so I'll probably drop my variant and pick yours instead.
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