NFSv4 allows for the fact that filesystems may be replicated across
several servers or that they may be migrated to a backup server in case of
failure of the primary server.
fs_locations is an NFSv4 operation for retrieving information about the
location of migrated and/or replicated filesystems.
Based on an initial implementation by Jiaying Zhang <jiayingz@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
In RFC3530, the RENEW operation is allowed to use either
the same principal, RPC security flavour and (if RPCSEC_GSS), the same
mechanism and service that was used for SETCLIENTID_CONFIRM
OR
Any principal, RPC security flavour and service combination that
currently has an OPEN file on the server.
Choose the latter since that doesn't require us to keep credentials for
the same principal for the entire duration of the mount.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
A closer reading of RFC3530 reveals that OPEN_DOWNGRADE must always
specify a access modes that have been the argument of a previous OPEN
operation.
IOW: doing OPEN(O_RDWR) and then OPEN_DOWNGRADE(O_WRONLY) is forbidden
unless the user called OPEN(O_WRONLY)
In order to fix that, we really need to track the three possible open
states separately.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
RFC 3530 states that for OPEN_DOWNGRADE "The share_access and share_deny
bits specified must be exactly equal to the union of the share_access and
share_deny bits specified for some subset of the OPENs in effect for
current openowner on the current file.
Setattr is currently violating the NFSv4 rules for OPEN_DOWNGRADE in that
it may cause a downgrade from OPEN4_SHARE_ACCESS_BOTH to
OPEN4_SHARE_ACCESS_WRITE despite the fact that there exists no open file
with O_WRONLY access mode.
Fix the problem by replacing nfs4_find_state() with a modified version of
nfs_find_open_context().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We must not remove the nfs4_state structure from the inode open lists
before we are in sequence lock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Storing a pointer to the struct rpc_task in the nfs_seqid is broken
since the nfs_seqid may be freed well after the task has been destroyed.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Make NFSv4 return the fully initialized file pointer with the
stateid that it created in the lookup w/intent.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4 file state-changing functions such as OPEN, CLOSE, LOCK,... are all
labelled with "sequence identifiers" in order to prevent the server from
reordering RPC requests, as this could cause its file state to
become out of sync with the client.
Currently the NFS client code enforces this ordering locally using
semaphores to restrict access to structures until the RPC call is done.
This, of course, only works with synchronous RPC calls, since the
user process must first grab the semaphore.
By dropping semaphores, and instead teaching the RPC engine to hold
the RPC calls until they are ready to be sent, we can extend this
process to work nicely with asynchronous RPC calls too.
This patch adds a new list called "rpc_sequence" that defines the order
of the RPC calls to be sent. We add one such list for each state_owner.
When an RPC call is ready to be sent, it checks if it is top of the
rpc_sequence list. If so, it proceeds. If not, it goes back to sleep,
and loops until it hits top of the list.
Once the RPC call has completed, it can then bump the sequence id counter,
and remove itself from the rpc_sequence list, and then wake up the next
sleeper.
Note that the state_owner sequence ids and lock_owner sequence ids are
all indexed to the same rpc_sequence list, so OPEN, LOCK,... requests
are all ordered w.r.t. each other.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add {get,set,list}xattr methods for nfs4. The new methods are no-ops, to be
used by subsequent ACL patch.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
