The attached patch makes NFS share superblocks between mounts from the same
server and FSID over the same protocol.
It does this by creating each superblock with a false root and returning the
real root dentry in the vfsmount presented by get_sb(). The root dentry set
starts off as an anonymous dentry if we don't already have the dentry for its
inode, otherwise it simply returns the dentry we already have.
We may thus end up with several trees of dentries in the superblock, and if at
some later point one of anonymous tree roots is discovered by normal filesystem
activity to be located in another tree within the superblock, the anonymous
root is named and materialises attached to the second tree at the appropriate
point.
Why do it this way? Why not pass an extra argument to the mount() syscall to
indicate the subpath and then pathwalk from the server root to the desired
directory? You can't guarantee this will work for two reasons:
(1) The root and intervening nodes may not be accessible to the client.
With NFS2 and NFS3, for instance, mountd is called on the server to get
the filehandle for the tip of a path. mountd won't give us handles for
anything we don't have permission to access, and so we can't set up NFS
inodes for such nodes, and so can't easily set up dentries (we'd have to
have ghost inodes or something).
With this patch we don't actually create dentries until we get handles
from the server that we can use to set up their inodes, and we don't
actually bind them into the tree until we know for sure where they go.
(2) Inaccessible symbolic links.
If we're asked to mount two exports from the server, eg:
mount warthog:/warthog/aaa/xxx /mmm
mount warthog:/warthog/bbb/yyy /nnn
We may not be able to access anything nearer the root than xxx and yyy,
but we may find out later that /mmm/www/yyy, say, is actually the same
directory as the one mounted on /nnn. What we might then find out, for
example, is that /warthog/bbb was actually a symbolic link to
/warthog/aaa/xxx/www, but we can't actually determine that by talking to
the server until /warthog is made available by NFS.
This would lead to having constructed an errneous dentry tree which we
can't easily fix. We can end up with a dentry marked as a directory when
it should actually be a symlink, or we could end up with an apparently
hardlinked directory.
With this patch we need not make assumptions about the type of a dentry
for which we can't retrieve information, nor need we assume we know its
place in the grand scheme of things until we actually see that place.
This patch reduces the possibility of aliasing in the inode and page caches for
inodes that may be accessed by more than one NFS export. It also reduces the
number of superblocks required for NFS where there are many NFS exports being
used from a server (home directory server + autofs for example).
This in turn makes it simpler to do local caching of network filesystems, as it
can then be guaranteed that there won't be links from multiple inodes in
separate superblocks to the same cache file.
Obviously, cache aliasing between different levels of NFS protocol could still
be a problem, but at least that gives us another key to use when indexing the
cache.
This patch makes the following changes:
(1) The server record construction/destruction has been abstracted out into
its own set of functions to make things easier to get right. These have
been moved into fs/nfs/client.c.
All the code in fs/nfs/client.c has to do with the management of
connections to servers, and doesn't touch superblocks in any way; the
remaining code in fs/nfs/super.c has to do with VFS superblock management.
(2) The sequence of events undertaken by NFS mount is now reordered:
(a) A volume representation (struct nfs_server) is allocated.
(b) A server representation (struct nfs_client) is acquired. This may be
allocated or shared, and is keyed on server address, port and NFS
version.
(c) If allocated, the client representation is initialised. The state
member variable of nfs_client is used to prevent a race during
initialisation from two mounts.
(d) For NFS4 a simple pathwalk is performed, walking from FH to FH to find
the root filehandle for the mount (fs/nfs/getroot.c). For NFS2/3 we
are given the root FH in advance.
(e) The volume FSID is probed for on the root FH.
(f) The volume representation is initialised from the FSINFO record
retrieved on the root FH.
(g) sget() is called to acquire a superblock. This may be allocated or
shared, keyed on client pointer and FSID.
(h) If allocated, the superblock is initialised.
(i) If the superblock is shared, then the new nfs_server record is
discarded.
(j) The root dentry for this mount is looked up from the root FH.
(k) The root dentry for this mount is assigned to the vfsmount.
(3) nfs_readdir_lookup() creates dentries for each of the entries readdir()
returns; this function now attaches disconnected trees from alternate
roots that happen to be discovered attached to a directory being read (in
the same way nfs_lookup() is made to do for lookup ops).
The new d_materialise_unique() function is now used to do this, thus
permitting the whole thing to be done under one set of locks, and thus
avoiding any race between mount and lookup operations on the same
directory.
(4) The client management code uses a new debug facility: NFSDBG_CLIENT which
is set by echoing 1024 to /proc/net/sunrpc/nfs_debug.
(5) Clone mounts are now called xdev mounts.
(6) Use the dentry passed to the statfs() op as the handle for retrieving fs
statistics rather than the root dentry of the superblock (which is now a
dummy).
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Move the rpc_ops from the nfs_server struct to the nfs_client struct as they're
common to all server records of a particular NFS protocol version.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Make better use of inode* dereferencing macros to hide dereferencing chains
(including NFS_PROTO and NFS_CLIENT).
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add some extra const qualifiers into NFS.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Generalise the nfs_client structure by:
(1) Moving nfs_client to a more general place (nfs_fs_sb.h).
(2) Renaming its maintenance routines to be non-NFS4 specific.
(3) Move those maintenance routines to a new non-NFS4 specific file (client.c)
and move the declarations to internal.h.
(4) Make nfs_find/get_client() take a full sockaddr_in to include the port
number (will be required for NFS2/3).
(5) Make nfs_find/get_client() take the NFS protocol version (again will be
required to differentiate NFS2, 3 & 4 client records).
Also:
(6) Make nfs_client construction proceed akin to inodes, marking them as under
construction and providing a function to indicate completion.
(7) Make nfs_get_client() wait interruptibly if it finds a client that it can
share, but that client is currently being constructed.
(8) Make nfs4_create_client() use (6) and (7) instead of locking cl_sem.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a set_capabilities NFS RPC op so that the server capabilities can be set.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add a lookup filehandle NFS RPC op so that a file handle can be looked up
without requiring dentries and inodes and other VFS stuff when doing an NFS4
pathwalk during mounting.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Rename nfs_server::nfs4_state to nfs_client as it will be used to represent the
client state for NFS2 and NFS3 also.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Rename struct nfs4_client to struct nfs_client so that it can become the basis
for a general client record for NFS2 and NFS3 in addition to NFS4.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This is needed in order to handle any NFS4ERR_DELAY errors that might be
returned by the server. It also ensures that we map the NFSv4 errors before
they are returned to userland.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 71c12b3f0abc7501f6ed231a6d17bc9c05a238dc commit)
Use FL_ACCESS flag to test and/or wait for local locks before we try
requesting a lock from the server
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Use the new behaviour of {flock,posix}_file_lock(F_UNLCK) to determine if
we held a lock, and only send the RPC request to the server if this was the
case.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
As fs/nfs/inode.c is rather large, heterogenous and unwieldy, the attached
patch splits it up into a number of files:
(*) fs/nfs/inode.c
Strictly inode specific functions.
(*) fs/nfs/super.c
Superblock management functions for NFS and NFS4, normal access, clones
and referrals. The NFS4 superblock functions _could_ move out into a
separate conditionally compiled file, but it's probably not worth it as
there're so many common bits.
(*) fs/nfs/namespace.c
Some namespace-specific functions have been moved here.
(*) fs/nfs/nfs4namespace.c
NFS4-specific namespace functions (this could be merged into the previous
file). This file is conditionally compiled.
(*) fs/nfs/internal.h
Inter-file declarations, plus a few simple utility functions moved from
fs/nfs/inode.c.
Additionally, all the in-.c-file externs have been moved here, and those
files they were moved from now includes this file.
For the most part, the functions have not been changed, only some multiplexor
functions have changed significantly.
I've also:
(*) Added some extra banner comments above some functions.
(*) Rearranged the function order within the files to be more logical and
better grouped (IMO), though someone may prefer a different order.
(*) Reduced the number of #ifdefs in .c files.
(*) Added missing __init and __exit directives.
Signed-Off-By: David Howells <dhowells@redhat.com>
Respond to a moved error on NFS lookup by setting up the referral.
Note: We don't actually follow the referral during lookup/getattr, but
later when we detect fsid mismatch in inode revalidation (similar to the
processing done for cloning submounts). Referrals will have fake attributes
until they are actually followed or traversed.
Signed-off-by: Manoj Naik <manoj@almaden.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This is (similar to getattr bitmap) but includes fs_locations and
mounted_on_fileid attributes. Use this bitmap for encoding in fs_locations
requests.
Note: We can probably do better by requesting locations as part of fsinfo
itself.
Signed-off-by: Manoj Naik <manoj@almaden.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Per referral draft, only fs_locations, fsid, and mounted_on_fileid can be
requested in a GETATTR on referrals.
Signed-off-by: Manoj Naik <manoj@almaden.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Use component4-style formats for decoding list of servers and pathnames in
fs_locations.
Signed-off-by: Manoj Naik <manoj@almaden.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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>
Whenever the directory changes, we want to make sure that we always
invalidate its page cache. Fix up update_changeattr() and
nfs_mark_for_revalidate() so that they do so.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the call to nfs_intent_set_file() fails to open a file in
nfs4_proc_create(), we should return an error.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Thanks to Frank Filz for pointing out that we list system.nfs4_acl extended
attribute even on filesystems where we don't actually support nfs4_acl.
This is inconsistent with the e.g. ext3 POSIX ACL behaviour, and seems to
annoy cp.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently this will not happen if we exit before rpc_new_task() was called.
Also fix up rpc_run_task() to do the same (for consistency).
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently it returns NULL, which usually gets interpreted as ENOMEM. In
fact it can mean a host of issues.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Same callback hierarchy inversion as for the NFS write calls. This patch is
not strictly speaking needed by the O_DIRECT code, but avoids confusing
differences between the asynchronous read and write code.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This patch inverts the callback hierarchy for NFS write calls.
Instead of having the NFSv2/v3/v4-specific code set up the RPC callback
ops, we allow the original caller to do so. This allows for more
flexibility w.r.t. how to set up and tear down the nfs_write_data
structure while still allowing the NFSv3/v4 code to perform error
handling.
The greater flexibility is needed by the asynchronous O_DIRECT code, which
wants to be able to hold on to the original nfs_write_data structures after
the WRITE RPC call has completed in order to be able to replay them if the
COMMIT call determines that the server has rebooted.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Make an inode or an nfs_server struct available in the logic that handles
JUKEBOX/DELAY type errors so the NFS client can account for them.
This patch is split out from the main nfs iostat patch to highlight minor
architectural changes required to support this statistic.
Test plan:
None.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
nfs4_open_revalidate: 'res' may be used uninitialized
nfs4_callback_compound: ‘hdr_res.nops’ may be used uninitialized
'op_nr’ may be used uninitialized
encode_getattr_res: ‘savep’ may be used uninitialized
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
My previous "const static" vs "static const" cleanup missed a single case,
patch below takes care of it.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
It turns out that nfs4_proc_get_root() may return raw NFSv4 errors instead of
mapping them to kernel errors. Problem spotted by Neil Horman
<nhorman@tuxdriver.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Upon return of a write delegation, the server will almost always bump the
change attribute. Ensure that we pick up that change so that we don't
invalidate our data cache unnecessarily.
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>
When recovering from a delegation recall or a network partition, we need
to replay open(O_RDWR), open(O_RDONLY) and open(O_WRONLY) separately.
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>
OPEN is a stateful operation, so we must ensure that it always
completes. In order to allow users to interrupt the operation,
we need to make the RPC call asynchronous, and then wait on
completion (or cancel).
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
