The way that credentials are handled in the flexfiles client is currently wrong. It only keeps one set of credentials per mirror object, but those objects can be shared between read and rw layout segments If the server hands out different credentials for read and rw layouts, then you can end up in a situation where the client will end up issuing writes with the wrong uid. This is visible by simply mounting a server that does hand out different creds for ro vs. rw layouts, opening the file for read, then opening it for write, and then issuing a write. At that point, the DS write calls will fail with EACCES. The client will then re-fetch the layout, but the creds are not updated, so the writes still fail. The client is then stuck at that point. This problem also means that the client is unable to recover after a layout is fenced, since the creds are never updated. This patchset cleans up some ugliness in how flexfiles rpc_creds are handled, adds a place to keep ro and rw creds per mirror, and allows those creds to be updated when a LAYOUTGET response contains different ones. We start with a few sunrpc patches that lay the groundwork to allow the creds to be accessible via RCU and to fix up a current wart where we can end up doing a GFP_KERNEL allocation while in a possible memory reclaim scenario. The flexfiles code is then changed to allow the creds to be swapped out as credential updates come in. The users of those creds then ensure that they take references to them in case they are swapped out, and put those references after the calls are dispatched. Only lightly tested so far (cthon and fstests) but it does fix the original problem. Jeff Layton (7): sunrpc: allow generic_match to handle creds with NULL group_info ptr sunrpc: plumb gfp_t parm into crcreate operation sunrpc: add a get_rpccred_rcu inline nfs: don't call nfs4_ff_layout_prepare_ds from ff_layout_get_ds_cred nfs: have ff_layout_get_ds_cred take a reference to the cred nfs: get a reference to the credential in ff_layout_alloc_lseg nfs: have flexfiles mirror keep creds for both ro and rw layouts Weston Andros Adamson (1): sunrpc: add rpc_lookup_generic_cred fs/nfs/flexfilelayout/flexfilelayout.c | 59 ++++++++++++++++++----- fs/nfs/flexfilelayout/flexfilelayout.h | 5 +- fs/nfs/flexfilelayout/flexfilelayoutdev.c | 78 +++++++++++-------------------- include/linux/sunrpc/auth.h | 23 ++++++++- net/sunrpc/auth.c | 4 +- net/sunrpc/auth_generic.c | 22 ++++++--- net/sunrpc/auth_gss/auth_gss.c | 6 +-- net/sunrpc/auth_unix.c | 6 +-- 8 files changed, 122 insertions(+), 81 deletions(-) -- 2.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
