| Message ID | 20210326173227.96363-2-jlayton@kernel.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [RFC,v5,01/19] vfs: export new_inode_pseudo | expand |
On Fri, Mar 26, 2021 at 01:32:09PM -0400, Jeff Layton wrote: > Ceph needs to be able to allocate inodes ahead of a create that might > involve a fscrypt-encrypted inode. new_inode() almost fits the bill, > but it puts the inode on the sb->s_inodes list and when we go to hash > it, that might be done again. > > We could work around that by setting I_CREATING on the new inode, but > that causes ilookup5 to return -ESTALE if something tries to find it > before I_NEW is cleared. To work around all of this, just use > new_inode_pseudo which doesn't add it to the list. > > Cc: Al Viro <viro@zeniv.linux.org.uk> > Signed-off-by: Jeff Layton <jlayton@kernel.org> IIRC, this looked like a bug in ilookup5(). Did you come to the conclusion that it's not actually a bug? - Eric
On Wed, 2021-04-07 at 18:08 -0700, Eric Biggers wrote: > On Fri, Mar 26, 2021 at 01:32:09PM -0400, Jeff Layton wrote: > > Ceph needs to be able to allocate inodes ahead of a create that might > > involve a fscrypt-encrypted inode. new_inode() almost fits the bill, > > but it puts the inode on the sb->s_inodes list and when we go to hash > > it, that might be done again. > > > > We could work around that by setting I_CREATING on the new inode, but > > that causes ilookup5 to return -ESTALE if something tries to find it > > before I_NEW is cleared. To work around all of this, just use > > new_inode_pseudo which doesn't add it to the list. > > > > Cc: Al Viro <viro@zeniv.linux.org.uk> > > Signed-off-by: Jeff Layton <jlayton@kernel.org> > > IIRC, this looked like a bug in ilookup5(). Did you come to the conclusion that > it's not actually a bug? > Yes. Al pointed out that it's desirable behavior for most (simpler) filesystems. Basically, nothing should have presented the filehandle for this inode to a client until after I_NEW has been cleared. So, any attempt to look it up should give you back ESTALE at this point. I'm not married to this approach however. If there's a better way to do this, then I'm happy to consider it. -- Jeff Layton <jlayton@kernel.org>
diff --git a/fs/inode.c b/fs/inode.c index a047ab306f9a..0745dc5d0924 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -935,6 +935,7 @@ struct inode *new_inode_pseudo(struct super_block *sb) } return inode; } +EXPORT_SYMBOL(new_inode_pseudo); /** * new_inode - obtain an inode
Ceph needs to be able to allocate inodes ahead of a create that might involve a fscrypt-encrypted inode. new_inode() almost fits the bill, but it puts the inode on the sb->s_inodes list and when we go to hash it, that might be done again. We could work around that by setting I_CREATING on the new inode, but that causes ilookup5 to return -ESTALE if something tries to find it before I_NEW is cleared. To work around all of this, just use new_inode_pseudo which doesn't add it to the list. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jeff Layton <jlayton@kernel.org> --- fs/inode.c | 1 + 1 file changed, 1 insertion(+)