This patchset represents a first draft at making cifs detect hardlinks at inode creation time. Currently, cifs has a pretty broken mechanism where all dentries get a new inode and hardlinks aren't handled at the VFS layer. Presumably this is because getting inode numbers from windows servers has a performance cost (separate call to the server). The problem is that hardlinks aren't detected by the VFS so we have to try to detect them when we think it will matter. It also means that there isn't cache consistency between hardlinked inodes. This patch is intended as a first stab at changing this for inodes on posix mounts. With posix extensions we generally get a "uniqueid" value for free from the server when we get inode attributes. The SNIA docs state that the UniqueId is unique in the scope of the share, and the MS docs seem to hint that it's per-machine unique value. Either way, I think it's safe enough not to worry about collisions. With this change, we'll probably want to make "serverino" the default (and maybe make it hardcoded on) when posix extensions are enabled. This set just focuses on the posix extension codepaths. Once I get this settled, I'll take a crack at fixing up the non-posix codepaths similarly (they'll be a bit more work -- more functions will need to be broken up, etc). The set here seems to work, but there's still more to be done: 1) how to handle an unexpected inode number change (consider a rename or a delete and recreate event that happens from another client or server). Right now, I'm not detecting this, but I think we probably need to consider what to do for it. 2) how to deal with non-posix extensions? When serverino is disabled, I think we'll want to use iunique() to generate new inode numbers. We could also consider making that the default as well. Anyway...the set isn't quite complete, but I'd like to post this to gather comments and suggestions and as a checkpoint to make sure I'm doing this reasonably correctly. Jeff Layton (3): cifs: rename cifs_iget to cifs_root_iget cifs: add new cifs_iget_unix_basic function cifs: add cifs_iget_unix and have readdir codepath use it fs/cifs/cifsfs.c | 2 +- fs/cifs/cifsfs.h | 15 +++++- fs/cifs/cifsglob.h | 1 + fs/cifs/cifsproto.h | 8 ++- fs/cifs/dir.c | 12 ++-- fs/cifs/inode.c | 158 ++++++++++++++++++++++++++++++++++++-------------- fs/cifs/readdir.c | 147 +++++++++++++++++++++++++++++++++++------------ 7 files changed, 251 insertions(+), 92 deletions(-) -- 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
