I wanted to add a few things.... On Mon, 26 Oct 2015 13:18:17 +0100 Aurélien Aptel <aaptel@xxxxxxxx> wrote: > * How do you allocate a new dentry? That's too broad, forget this one. There are many functions to do that depending on what you want. > * What do d_obtain_alias() and d_splice_dentry() actually do? I've > read the doc strings several times but I still have a hard time > wrapping my head around it. To be more specific, where does d_obtain_alias() look for a dentry associated with the provided inode? I would guess in all the connected dentries for the inode superblock. If it's not there, what is the path of the newly allocated dentry? d_splice_alias() looks for an existing dentry associated with the provided inode and if it founds one, replaces it with the one provided. Correct? Really, I think my biggest misunderstanding is, what does it mean for a dentry to be disconnected? > The result I'm getting seems to indicate that when an intermediary > path element is inaccessible an alternate root dentry directly > pointing to the requested path is created. The problem is that the > prefixpath of that is not stored anywhere so when we ask for a > pattern to list the content of that share, we use the path of the > dentry from the root (which is, well /) instead of the share > prefixpath. To illustrate this: * User bill can only access HOST/share/sub/path and none of the intermediary path. * When we mount this path to /mnt we realize we cannot access intermediary path. * We create an alternative root which directly sores HOST/share/sub/path as / (but /sub/path/ is not stored anywhere!). * When we ls /mnt, we use this alternate root path. The function that builds the share path from a dentry (build_path_from_dentry) simply walk the d_parent dentry until it reach /. In that case it immediatly stops because the disconnected root is.. a root. It should use /sub/path instead. -- Aurélien Aptel / SUSE Labs Samba Team GPG: 1839 CB5F 9F5B FB9B AA97 8C99 03C8 A49B 521B D5D3 SUSE Linux GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
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