With the write_begin/write_end aops, page_symlink was broken because it
could no longer pass a GFP_NOFS type mask into the point where the
allocations happened. They are done in write_begin, which would always
assume that the filesystem can be entered from reclaim. This bug could
cause filesystem deadlocks.
The funny thing with having a gfp_t mask there is that it doesn't really
allow the caller to arbitrarily tinker with the context in which it can be
called. It couldn't ever be GFP_ATOMIC, for example, because it needs to
take the page lock. The only thing any callers care about is __GFP_FS
anyway, so turn that into a single flag.
Add a new flag for write_begin, AOP_FLAG_NOFS. Filesystems can now act on
this flag in their write_begin function. Change __grab_cache_page to
accept a nofs argument as well, to honour that flag (while we're there,
change the name to grab_cache_page_write_begin which is more instructive
and does away with random leading underscores).
This is really a more flexible way to go in the end anyway -- if a
filesystem happens to want any extra allocations aside from the pagecache
ones in ints write_begin function, it may now use GFP_KERNEL (rather than
GFP_NOFS) for common case allocations (eg. ocfs2_alloc_write_ctxt, for a
random example).
[kosaki.motohiro@jp.fujitsu.com: fix ubifs]
[kosaki.motohiro@jp.fujitsu.com: fix fuse]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Cleaned up the calling convention: just pass in the AOP flags
untouched to the grab_cache_page_write_begin() function. That
just simplifies everybody, and may even allow future expansion of the
logic. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
nfs4_map_errors() can become static.
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This patch adds client-side support to allow for callbacks other than
AUTH_SYS.
Signed-off-by: Olga Kornievskaia <aglo@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
3 call sites look at hdr.status before returning success.
hdr.status must be zero in this case so there's no point in this.
Currently, hdr.status is correctly processed at decode_op_hdr time
if the op status cannot be decoded.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When there are no op replies encoded in the compound reply
hdr.status still contains the overall status of the compound
rpc. This can happen, e.g., when the server returns a
NFS4ERR_MINOR_VERS_MISMATCH error.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Marten Gajda <marten.gajda@fernuni-hagen.de> states:
I tracked the problem down to the function nfs4_do_open_expired.
Within this function _nfs4_open_expired is called and may return
-NFS4ERR_DELAY. When a further call to _nfs4_open_expired is
executed and does not return -NFS4ERR_DELAY the "exception.retry"
variable is not reset to 0, causing the loop to iterate again
(and as long as err != -NFS4ERR_DELAY, probably forever)
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Hi.
I've been looking at a bugzilla which describes a problem where
a customer was advised to use either the "noac" or "actimeo=0"
mount options to solve a consistency problem that they were
seeing in the file attributes. It turned out that this solution
did not work reliably for them because sometimes, the local
attribute cache was believed to be valid and not timed out.
(With an attribute cache timeout of 0, the cache should always
appear to be timed out.)
In looking at this situation, it appears to me that the problem
is that the attribute cache timeout code has an off-by-one
error in it. It is assuming that the cache is valid in the
region, [read_cache_jiffies, read_cache_jiffies + attrtimeo]. The
cache should be considered valid only in the region,
[read_cache_jiffies, read_cache_jiffies + attrtimeo). With this
change, the options, "noac" and "actimeo=0", work as originally
expected.
This problem was previously addressed by special casing the
attrtimeo == 0 case. However, since the problem is only an off-
by-one error, the cleaner solution is address the off-by-one
error and thus, not require the special case.
Thanx...
ps
Signed-off-by: Peter Staubach <staubach@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This ensures that we don't have to look up the dentry again after we return
the delegation if we know that the directory didn't change.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently, the callback server is listening on IPv6 if it is enabled. This
means that IPv4 addresses will always be mapped.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the client is not using a delegation, the right thing to do is to return
it as soon as possible. This helps reduce the amount of state the server
has to track, as well as reducing the potential for conflicts with other
clients.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Let the actual delegreturn stuff be run in the state manager thread rather
than allocating a separate kthread.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We really shouldn't be resetting the sequence ids when doing state
expiration recovery, since we don't know if the server still remembers our
previous state owners. There are servers out there that do attempt to
preserve client state even if the lease has expired. Such a server would
only release that state if a conflicting OPEN request occurs.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a delegation cleanup phase to the state management loop, and do the
NFS4ERR_CB_PATH_DOWN recovery there.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a flag to mark delegations as requiring return, then run a garbage
collector. In the future, this will allow for more flexible delegation
management, where delegations may be marked for return if it turns out
that they are not being referenced.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv4 defines a number of state errors which the client does not currently
handle. Among those we should worry about are:
NFS4ERR_ADMIN_REVOKED - the server's administrator revoked our locks
and/or delegations.
NFS4ERR_BAD_STATEID - the client and server are out of sync, possibly
due to a delegation return racing with an OPEN
request.
NFS4ERR_OPENMODE - the client attempted to do something not sanctioned
by the open mode of the stateid. Should normally just
occur as a result of a delegation return race.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Now that we're using the flags to indicate state that needs to be
recovered, as well as having implemented proper refcounting and spinlocking
on the state and open_owners, we can get rid of nfs_client->cl_sem. The
only remaining case that was dubious was the file locking, and that case is
now covered by the nfsi->rwsem.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The unlock path is currently failing to take the nfs_client->cl_sem read
lock, and hence the recovery path may see locks disappear from underneath
it.
Also ensure that it takes the nfs_inode->rwsem read lock so that it there
is no conflict with delegation recalls.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the client for some reason is not able to recover all its state within
the time allotted for the grace period, and the server reboots again, the
client is not allowed to recover the state that was 'lost' using reboot
recovery.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Without an extra lock, we cannot just assume that the delegation->inode is
valid when we're traversing the rcu-protected nfs_client lists. Use the
delegation->lock to ensure that it is truly valid.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
When we can update_open_stateid(), we need to be certain that we don't
race with a delegation return. While we could do this by grabbing the
nfs_client->cl_lock, a dedicated spin lock in the delegation structure
will scale better.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the admin has specified the "noresvport" option for an NFS mount
point, the kernel's NFS client uses an unprivileged source port for
the main NFS transport. The kernel's lockd client should use an
unprivileged port in this case as well.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the admin has specified the "noresvport" option for an NFS mount
point, the kernel's NFS client uses an unprivileged source port for
the main NFS transport. The kernel's mountd client should use an
unprivileged port in this case as well.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The standard default security setting for NFS is AUTH_SYS. An NFS
client connects to NFS servers via a privileged source port and a
fixed standard destination port (2049). The client sends raw uid and
gid numbers to identify users making NFS requests, and the server
assumes an appropriate authority on the client has vetted these
values because the source port is privileged.
On Linux, by default in-kernel RPC services use a privileged port in
the range between 650 and 1023 to avoid using source ports of well-
known IP services. Using such a small range limits the number of NFS
mount points and the number of unique NFS servers to which a client
can connect concurrently.
An NFS client can use unprivileged source ports to expand the range of
source port numbers, allowing more concurrent server connections and
more NFS mount points. Servers must explicitly allow NFS connections
from unprivileged ports for this to work.
In the past, bumping the value of the sunrpc.max_resvport sysctl on
the client would permit the NFS client to use unprivileged ports.
Bumping this setting also changes the maximum port number used by
other in-kernel RPC services, some of which still required a port
number less than 1023.
This is exacerbated by the way source port numbers are chosen by the
Linux RPC client, which starts at the top of the range and works
downwards. It means that bumping the maximum means all RPC services
requesting a source port will likely get an unprivileged port instead
of a privileged one.
Changing this setting effects all NFS mount points on a client. A
sysadmin could not selectively choose which mount points would use
non-privileged ports and which could not.
Lastly, this mechanism of expanding the limit on the number of NFS
mount points was entirely undocumented.
To address the need for the NFS client to use a large range of source
ports without interfering with the activity of other in-kernel RPC
services, we introduce a new NFS mount option. This option explicitly
tells only the NFS client to use a non-privileged source port when
communicating with the NFS server for one specific mount point.
This new mount option is called "resvport," like the similar NFS mount
option on FreeBSD and Mac OS X. A sister patch for nfs-utils will be
submitted that documents this new option in nfs(5).
The default setting for this new mount option requires the NFS client
to use a privileged port, as before. Explicitly specifying the
"noresvport" mount option allows the NFS client to use an unprivileged
source port for this mount point when connecting to the NFS server
port.
This mount option is supported only for text-based NFS mounts.
[ Sidebar: it is widely known that security mechanisms based on the
use of privileged source ports are ineffective. However, the NFS
client can combine the use of unprivileged ports with the use of
secure authentication mechanisms, such as Kerberos. This allows a
large number of connections and mount points while ensuring a useful
level of security.
Eventually we may change the default setting for this option
depending on the security flavor used for the mount. For example,
if the mount is using only AUTH_SYS, then the default setting will
be "resvport;" if the mount is using a strong security flavor such
as krb5, the default setting will be "noresvport." ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[Trond.Myklebust@netapp.com: Fixed a bug whereby nfs4_init_client()
was being called with incorrect arguments.]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Make it possible for the NFSv4 mount set up logic to pass mount option
flags down the stack to nfs_create_rpc_client().
This is immediately useful if we want NFS mount options to modulate
settings of the underlying RPC transport, but it may be useful at some
later point if other parts of the NFSv4 mount initialization logic
want to know what the mount options are.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The nfs_create_rpc_client() function sets up an RPC client for an NFS
mount point. Add an option that allows it to set up an RPC transport
from an unprivileged port.
Instead of having nfs_create_rpc_client()'s callers retain local
knowledge about how to set up an RPC client, create a couple of flag
arguments to control the use of RPC_CLNT_CREATE flags.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up: convert nfs_mount() to take a single data structure argument to make
it simpler to add more arguments.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up: The nfs_mount() function is not to be used outside of the
NFS client. Move its public declaration to fs/nfs/internal.h.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Clean up: I'm about to move the declaration of nfs_mount into
fs/nfs/internal.h and include it in fs/nfs/nfsroot.c. There's a
conflicting definition of nfs_path in fs/nfs/internal.h and
fs/nfs/nfsroot.c, so rename the private one.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
aops->readpages() and its NFS helper readpage_async_filler() will only
be called to do readahead I/O for newly allocated pages. So it's not
necessary to test for the always 0 dirty/uptodate page flags.
The removal of nfs_wb_page() call also fixes a readahead bug: the NFS
readahead has been synchronous since 2.6.23, because that call will
clear PG_readahead, which is the reminder for asynchronous readahead.
More background: the PG_readahead page flag is shared with PG_reclaim,
one for read path and the other for write path. clear_page_dirty_for_io()
unconditionally clears PG_readahead to prevent possible readahead residuals,
assuming itself to be always called in the write path. However, NFS is one
and the only exception in that it _always_ calls clear_page_dirty_for_io()
in the read path, i.e. for readpages()/readpage().
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Wu Fengguang <wfg@linux.intel.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
