linux-sg2042/include/linux/nfs_fs_sb.h

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#ifndef _NFS_FS_SB
#define _NFS_FS_SB
#include <linux/list.h>
#include <linux/backing-dev.h>
#include <linux/idr.h>
#include <linux/wait.h>
nfs41: sessions client infrastructure NFSv4.1 Sessions basic data types, initialization, and destruction. The session is always associated with a struct nfs_client that holds the exchange_id results. Signed-off-by: Rahul Iyer <iyer@netapp.com> Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [remove extraneous rpc_clnt pointer, use the struct nfs_client cl_rpcclient. remove the rpc_clnt parameter from nfs4 nfs4_init_session] Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Use the presence of a session to determine behaviour instead of the minorversion number.] Signed-off-by: Andy Adamson <andros@netapp.com> [constified nfs4_has_session's struct nfs_client parameter] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Rename nfs4_put_session() to nfs4_destroy_session() and call it from nfs4_free_client() not nfs4_free_server(). Also get rid of nfs4_get_session() and the ref_count in nfs4_session struct as keeping track of nfs_client should be sufficient] Signed-off-by: Alexandros Batsakis <Alexandros.Batsakis@netapp.com> [nfs41: pass rsize and wsize into nfs4_init_session] Signed-off-by: Andy Adamson <andros@netapp.com> [separated out removal of rpc_clnt parameter from nfs4_init_session ot a patch of its own] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Pass the nfs_client pointer into nfs4_alloc_session] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: don't assign to session->clp->cl_session in nfs4_destroy_session] [nfs41: fixup nfs4_clear_client_minor_version] [introduce nfs4_clear_client_minor_version() in this patch] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Refactor nfs4_init_session] Moved session allocation into nfs4_init_client_minor_version, called from nfs4_init_client. Leave rwise and wsize initialization in nfs4_init_session, called from nfs4_init_server. Reverted moving of nfs_fsid definition to nfs_fs_sb.h Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Move NFS4_MAX_SLOT_TABLE define from under CONFIG_NFS_V4_1] [Fix comile error when CONFIG_NFS_V4_1 is not set.] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [moved nfs4_init_slot_table definition to "create_session operation"] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: alloc session with GFP_KERNEL] Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-04-01 21:21:53 +08:00
#include <linux/nfs_xdr.h>
#include <linux/sunrpc/xprt.h>
#include <linux/atomic.h>
nfs41: sessions client infrastructure NFSv4.1 Sessions basic data types, initialization, and destruction. The session is always associated with a struct nfs_client that holds the exchange_id results. Signed-off-by: Rahul Iyer <iyer@netapp.com> Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [remove extraneous rpc_clnt pointer, use the struct nfs_client cl_rpcclient. remove the rpc_clnt parameter from nfs4 nfs4_init_session] Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Use the presence of a session to determine behaviour instead of the minorversion number.] Signed-off-by: Andy Adamson <andros@netapp.com> [constified nfs4_has_session's struct nfs_client parameter] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Rename nfs4_put_session() to nfs4_destroy_session() and call it from nfs4_free_client() not nfs4_free_server(). Also get rid of nfs4_get_session() and the ref_count in nfs4_session struct as keeping track of nfs_client should be sufficient] Signed-off-by: Alexandros Batsakis <Alexandros.Batsakis@netapp.com> [nfs41: pass rsize and wsize into nfs4_init_session] Signed-off-by: Andy Adamson <andros@netapp.com> [separated out removal of rpc_clnt parameter from nfs4_init_session ot a patch of its own] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Pass the nfs_client pointer into nfs4_alloc_session] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: don't assign to session->clp->cl_session in nfs4_destroy_session] [nfs41: fixup nfs4_clear_client_minor_version] [introduce nfs4_clear_client_minor_version() in this patch] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Refactor nfs4_init_session] Moved session allocation into nfs4_init_client_minor_version, called from nfs4_init_client. Leave rwise and wsize initialization in nfs4_init_session, called from nfs4_init_server. Reverted moving of nfs_fsid definition to nfs_fs_sb.h Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Move NFS4_MAX_SLOT_TABLE define from under CONFIG_NFS_V4_1] [Fix comile error when CONFIG_NFS_V4_1 is not set.] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [moved nfs4_init_slot_table definition to "create_session operation"] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: alloc session with GFP_KERNEL] Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-04-01 21:21:53 +08:00
struct nfs4_session;
struct nfs_iostats;
struct nlm_host;
nfs41: introduce nfs4_call_sync Use nfs4_call_sync rather than rpc_call_sync to provide for a nfs41 sessions-enabled interface for sessions manipulation. The nfs41 rpc logic uses the rpc_call_prepare method to recover and create the session, as well as selecting a free slot id and the rpc_call_done to free the slot and update slot table related metadata. In the coming patches we'll add rpc prepare and done routines for setting up the sequence op and processing the sequence result. Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: nfs4_call_sync] As per 11-14-08 review. Squash into "nfs41: introduce nfs4_call_sync" and "nfs41: nfs4_setup_sequence" Define two functions one for v4 and one for v41 add a pointer to struct nfs4_client to the correct one. Signed-off-by: Andy Adamson <andros@netapp.com> [added BUG() in _nfs4_call_sync_session if !CONFIG_NFS_V4_1] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: check for session not minorversion] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [group minorversion specific stuff together] Signed-off-by: Alexandros Batsakis <Alexandros.Batsakis@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Andy Adamson <andros@netapp.com> [nfs41: fixup nfs4_clear_client_minor_version] [introduce nfs4_init_client_minor_version() in this patch] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [cleaned-up patch: got rid of nfs_call_sync_t, dprintks, cosmetics, extra server defs] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-04-01 21:22:03 +08:00
struct nfs4_sequence_args;
struct nfs4_sequence_res;
struct nfs_server;
struct nfs4_minor_version_ops;
struct nfs41_server_scope;
struct nfs41_impl_id;
/*
* The nfs_client identifies our client state to the server.
*/
struct nfs_client {
atomic_t cl_count;
atomic_t cl_mds_count;
int cl_cons_state; /* current construction state (-ve: init error) */
#define NFS_CS_READY 0 /* ready to be used */
#define NFS_CS_INITING 1 /* busy initialising */
nfs41: add session setup to the state manager At mount, nfs_alloc_client sets the cl_state NFS4CLNT_LEASE_EXPIRED bit and nfs4_alloc_session sets the NFS4CLNT_SESSION_SETUP bit, so both bits are set when nfs4_lookup_root calls nfs4_recover_expired_lease which schedules the nfs4_state_manager and waits for it to complete. Place the session setup after the clientid establishment in nfs4_state_manager so that the session is setup right after the clientid has been established without rescheduling the state manager. Unlike nfsv4.0, the nfs_client struct is not ready to use until the session has been established. Postpone marking the nfs_client struct to NFS_CS_READY until after a successful CREATE_SESSION call so that other threads cannot use the client until the session is established. If the EXCHANGE_ID call fails and the session has not been setup (the NFS4CLNT_SESSION_SETUP bit is set), mark the client with the error and return. If the session setup CREATE_SESSION call fails with NFS4ERR_STALE_CLIENTID which could occur due to server reboot or network partition inbetween the EXCHANGE_ID and CREATE_SESSION call, reset the NFS4CLNT_LEASE_EXPIRED and NFS4CLNT_SESSION_SETUP bits and try again. If the CREATE_SESSION call fails with other errors, mark the client with the error and return. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: NFS_CS_SESSION_SETUP cl_cons_state for back channel setup] On session setup, the CREATE_SESSION reply races with the server back channel probe which needs to succeed to setup the back channel. Set a new cl_cons_state NFS_CS_SESSION_SETUP just prior to the CREATE_SESSION call and add it as a valid state to nfs_find_client so that the client back channel can find the nfs_client struct and won't drop the server backchannel probe. Use a new cl_cons_state so that NFSv4.0 back channel behaviour which only sets NFS_CS_READY is unchanged. Adjust waiting on the nfs_client_active_wq accordingly. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: rename NFS_CS_SESSION_SETUP to NFS_CS_SESSION_INITING] Signed-off-by: Andy Adamson <andros@netapp.com> [nfs41: set NFS_CL_SESSION_INITING in alloc_session] Signed-off-by: Andy Adamson <andros@netapp.com> [nfs41: move session setup into a function] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [moved nfs4_proc_create_session declaration here] Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-04-01 21:22:38 +08:00
#define NFS_CS_SESSION_INITING 2 /* busy initialising session */
unsigned long cl_res_state; /* NFS resources state */
#define NFS_CS_CALLBACK 1 /* - callback started */
#define NFS_CS_IDMAP 2 /* - idmap started */
#define NFS_CS_RENEWD 3 /* - renewd started */
#define NFS_CS_STOP_RENEW 4 /* no more state to renew */
#define NFS_CS_CHECK_LEASE_TIME 5 /* need to check lease time */
unsigned long cl_flags; /* behavior switches */
#define NFS_CS_NORESVPORT 0 /* - use ephemeral src port */
#define NFS_CS_DISCRTRY 1 /* - disconnect on RPC retry */
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#define NFS_CS_MIGRATION 2 /* - transparent state migr */
#define NFS_CS_INFINITE_SLOTS 3 /* - don't limit TCP slots */
#define NFS_CS_NO_RETRANS_TIMEOUT 4 /* - Disable retransmit timeouts */
struct sockaddr_storage cl_addr; /* server identifier */
size_t cl_addrlen;
char * cl_hostname; /* hostname of server */
char * cl_acceptor; /* GSSAPI acceptor name */
struct list_head cl_share_link; /* link in global client list */
struct list_head cl_superblocks; /* List of nfs_server structs */
struct rpc_clnt * cl_rpcclient;
const struct nfs_rpc_ops *rpc_ops; /* NFS protocol vector */
int cl_proto; /* Network transport protocol */
struct nfs_subversion * cl_nfs_mod; /* pointer to nfs version module */
u32 cl_minorversion;/* NFSv4 minorversion */
struct rpc_cred *cl_machine_cred;
#if IS_ENABLED(CONFIG_NFS_V4)
struct list_head cl_ds_clients; /* auth flavor data servers */
u64 cl_clientid; /* constant */
nfs4_verifier cl_confirm; /* Clientid verifier */
unsigned long cl_state;
spinlock_t cl_lock;
unsigned long cl_lease_time;
unsigned long cl_last_renewal;
struct delayed_work cl_renewd;
struct rpc_wait_queue cl_rpcwaitq;
/* idmapper */
struct idmap * cl_idmap;
/* Client owner identifier */
const char * cl_owner_id;
u32 cl_cb_ident; /* v4.0 callback identifier */
const struct nfs4_minor_version_ops *cl_mvops;
unsigned long cl_mig_gen;
/* NFSv4.0 transport blocking */
struct nfs4_slot_table *cl_slot_tbl;
/* The sequence id to use for the next CREATE_SESSION */
u32 cl_seqid;
/* The flags used for obtaining the clientid during EXCHANGE_ID */
u32 cl_exchange_flags;
struct nfs4_session *cl_session; /* shared session */
NFS: Discover NFSv4 server trunking when mounting "Server trunking" is a fancy named for a multi-homed NFS server. Trunking might occur if a client sends NFS requests for a single workload to multiple network interfaces on the same server. There are some implications for NFSv4 state management that make it useful for a client to know if a single NFSv4 server instance is multi-homed. (Note this is only a consideration for NFSv4, not for legacy versions of NFS, which are stateless). If a client cares about server trunking, no NFSv4 operations can proceed until that client determines who it is talking to. Thus server IP trunking discovery must be done when the client first encounters an unfamiliar server IP address. The nfs_get_client() function walks the nfs_client_list and matches on server IP address. The outcome of that walk tells us immediately if we have an unfamiliar server IP address. It invokes nfs_init_client() in this case. Thus, nfs4_init_client() is a good spot to perform trunking discovery. Discovery requires a client to establish a fresh client ID, so our client will now send SETCLIENTID or EXCHANGE_ID as the first NFS operation after a successful ping, rather than waiting for an application to perform an operation that requires NFSv4 state. The exact process for detecting trunking is different for NFSv4.0 and NFSv4.1, so a minorversion-specific init_client callout method is introduced. CLID_INUSE recovery is important for the trunking discovery process. CLID_INUSE is a sign the server recognizes the client's nfs_client_id4 id string, but the client is using the wrong principal this time for the SETCLIENTID operation. The SETCLIENTID must be retried with a series of different principals until one works, and then the rest of trunking discovery can proceed. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-09-15 05:24:32 +08:00
bool cl_preserve_clid;
struct nfs41_server_owner *cl_serverowner;
struct nfs41_server_scope *cl_serverscope;
struct nfs41_impl_id *cl_implid;
/* nfs 4.1+ state protection modes: */
unsigned long cl_sp4_flags;
#define NFS_SP4_MACH_CRED_MINIMAL 1 /* Minimal sp4_mach_cred - state ops
* must use machine cred */
#define NFS_SP4_MACH_CRED_CLEANUP 2 /* CLOSE and LOCKU */
#define NFS_SP4_MACH_CRED_SECINFO 3 /* SECINFO and SECINFO_NO_NAME */
#define NFS_SP4_MACH_CRED_STATEID 4 /* TEST_STATEID and FREE_STATEID */
#define NFS_SP4_MACH_CRED_WRITE 5 /* WRITE */
#define NFS_SP4_MACH_CRED_COMMIT 6 /* COMMIT */
#endif /* CONFIG_NFS_V4 */
nfs41: sessions client infrastructure NFSv4.1 Sessions basic data types, initialization, and destruction. The session is always associated with a struct nfs_client that holds the exchange_id results. Signed-off-by: Rahul Iyer <iyer@netapp.com> Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [remove extraneous rpc_clnt pointer, use the struct nfs_client cl_rpcclient. remove the rpc_clnt parameter from nfs4 nfs4_init_session] Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Use the presence of a session to determine behaviour instead of the minorversion number.] Signed-off-by: Andy Adamson <andros@netapp.com> [constified nfs4_has_session's struct nfs_client parameter] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Rename nfs4_put_session() to nfs4_destroy_session() and call it from nfs4_free_client() not nfs4_free_server(). Also get rid of nfs4_get_session() and the ref_count in nfs4_session struct as keeping track of nfs_client should be sufficient] Signed-off-by: Alexandros Batsakis <Alexandros.Batsakis@netapp.com> [nfs41: pass rsize and wsize into nfs4_init_session] Signed-off-by: Andy Adamson <andros@netapp.com> [separated out removal of rpc_clnt parameter from nfs4_init_session ot a patch of its own] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Pass the nfs_client pointer into nfs4_alloc_session] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: don't assign to session->clp->cl_session in nfs4_destroy_session] [nfs41: fixup nfs4_clear_client_minor_version] [introduce nfs4_clear_client_minor_version() in this patch] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Refactor nfs4_init_session] Moved session allocation into nfs4_init_client_minor_version, called from nfs4_init_client. Leave rwise and wsize initialization in nfs4_init_session, called from nfs4_init_server. Reverted moving of nfs_fsid definition to nfs_fs_sb.h Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Move NFS4_MAX_SLOT_TABLE define from under CONFIG_NFS_V4_1] [Fix comile error when CONFIG_NFS_V4_1 is not set.] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [moved nfs4_init_slot_table definition to "create_session operation"] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: alloc session with GFP_KERNEL] Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-04-01 21:21:53 +08:00
/* Our own IP address, as a null-terminated string.
* This is used to generate the mv0 callback address.
*/
char cl_ipaddr[48];
#ifdef CONFIG_NFS_FSCACHE
struct fscache_cookie *fscache; /* client index cache cookie */
#endif
struct net *cl_net;
};
/*
* NFS client parameters stored in the superblock.
*/
struct nfs_server {
struct nfs_client * nfs_client; /* shared client and NFS4 state */
NFS: Share NFS superblocks per-protocol per-server per-FSID 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>
2006-08-23 08:06:13 +08:00
struct list_head client_link; /* List of other nfs_server structs
* that share the same client
*/
struct list_head master_link; /* link in master servers list */
struct rpc_clnt * client; /* RPC client handle */
struct rpc_clnt * client_acl; /* ACL RPC client handle */
struct nlm_host *nlm_host; /* NLM client handle */
struct nfs_iostats __percpu *io_stats; /* I/O statistics */
struct backing_dev_info backing_dev_info;
atomic_long_t writeback; /* number of writeback pages */
int flags; /* various flags */
unsigned int caps; /* server capabilities */
unsigned int rsize; /* read size */
unsigned int rpages; /* read size (in pages) */
unsigned int wsize; /* write size */
unsigned int wpages; /* write size (in pages) */
unsigned int wtmult; /* server disk block size */
unsigned int dtsize; /* readdir size */
unsigned short port; /* "port=" setting */
unsigned int bsize; /* server block size */
unsigned int acregmin; /* attr cache timeouts */
unsigned int acregmax;
unsigned int acdirmin;
unsigned int acdirmax;
unsigned int namelen;
unsigned int options; /* extra options enabled by mount */
#define NFS_OPTION_FSCACHE 0x00000001 /* - local caching enabled */
2012-09-15 05:24:11 +08:00
#define NFS_OPTION_MIGRATION 0x00000002 /* - NFSv4 migration enabled */
NFS: Share NFS superblocks per-protocol per-server per-FSID 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>
2006-08-23 08:06:13 +08:00
struct nfs_fsid fsid;
NFS: Share NFS superblocks per-protocol per-server per-FSID 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>
2006-08-23 08:06:13 +08:00
__u64 maxfilesize; /* maximum file size */
struct timespec time_delta; /* smallest time granularity */
unsigned long mount_time; /* when this fs was mounted */
struct super_block *super; /* VFS super block */
NFS: Share NFS superblocks per-protocol per-server per-FSID 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>
2006-08-23 08:06:13 +08:00
dev_t s_dev; /* superblock dev numbers */
struct nfs_auth_info auth_info; /* parsed auth flavors */
NFS: Share NFS superblocks per-protocol per-server per-FSID 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>
2006-08-23 08:06:13 +08:00
NFS: Define and create superblock-level objects Define and create superblock-level cache index objects (as managed by nfs_server structs). Each superblock object is created in a server level index object and is itself an index into which inode-level objects are inserted. Ideally there would be one superblock-level object per server, and the former would be folded into the latter; however, since the "nosharecache" option exists this isn't possible. The superblock object key is a sequence consisting of: (1) Certain superblock s_flags. (2) Various connection parameters that serve to distinguish superblocks for sget(). (3) The volume FSID. (4) The security flavour. (5) The uniquifier length. (6) The uniquifier text. This is normally an empty string, unless the fsc=xyz mount option was used to explicitly specify a uniquifier. The key blob is of variable length, depending on the length of (6). The superblock object is given no coherency data to carry in the auxiliary data permitted by the cache. It is assumed that the superblock is always coherent. This patch also adds uniquification handling such that two otherwise identical superblocks, at least one of which is marked "nosharecache", won't end up trying to share the on-disk cache. It will be possible to manually provide a uniquifier through a mount option with a later patch to avoid the error otherwise produced. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 23:42:42 +08:00
#ifdef CONFIG_NFS_FSCACHE
struct nfs_fscache_key *fscache_key; /* unique key for superblock */
struct fscache_cookie *fscache; /* superblock cookie */
#endif
u32 pnfs_blksize; /* layout_blksize attr */
#if IS_ENABLED(CONFIG_NFS_V4)
u32 attr_bitmask[3];/* V4 bitmask representing the set
of attributes supported on this
filesystem */
u32 attr_bitmask_nl[3];
/* V4 bitmask representing the
set of attributes supported
on this filesystem excluding
the label support bit. */
u32 cache_consistency_bitmask[3];
/* V4 bitmask representing the subset
of change attribute, size, ctime
and mtime attributes supported by
the server */
u32 acl_bitmask; /* V4 bitmask representing the ACEs
that are supported on this
filesystem */
u32 fh_expire_type; /* V4 bitmask representing file
handle volatility type for
this filesystem */
struct pnfs_layoutdriver_type *pnfs_curr_ld; /* Active layout driver */
struct rpc_wait_queue roc_rpcwaitq;
void *pnfs_ld_data; /* per mount point data */
/* the following fields are protected by nfs_client->cl_lock */
struct rb_root state_owners;
#endif
struct ida openowner_id;
struct ida lockowner_id;
NFS: Cache state owners after files are closed Servers have a finite amount of memory to store NFSv4 open and lock owners. Moreover, servers may have a difficult time determining when they can reap their state owner table, thanks to gray areas in the NFSv4 protocol specification. Thus clients should be careful to reuse state owners when possible. Currently Linux is not too careful. When a user has closed all her files on one mount point, the state owner's reference count goes to zero, and it is released. The next OPEN allocates a new one. A workload that serially opens and closes files can run through a large number of open owners this way. When a state owner's reference count goes to zero, slap it onto a free list for that nfs_server, with an expiry time. Garbage collect before looking for a state owner. This makes state owners for active users available for re-use. Now that there can be unused state owners remaining at umount time, purge the state owner free list when a server is destroyed. Also be sure not to reclaim unused state owners during state recovery. This change has benefits for the client as well. For some workloads, this approach drops the number of OPEN_CONFIRM calls from the same as the number of OPEN calls, down to just one. This reduces wire traffic and thus open(2) latency. Before this patch, untarring a kernel source tarball shows the OPEN_CONFIRM call counter steadily increasing through the test. With the patch, the OPEN_CONFIRM count remains at 1 throughout the entire untar. As long as the expiry time is kept short, I don't think garbage collection should be terribly expensive, although it does bounce the clp->cl_lock around a bit. [ At some point we should rationalize the use of the nfs_server ->destroy method. ] Signed-off-by: Chuck Lever <chuck.lever@oracle.com> [Trond: Fixed a garbage collection race and a few efficiency issues] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-12-07 05:13:48 +08:00
struct list_head state_owners_lru;
struct list_head layouts;
struct list_head delegations;
unsigned long mig_gen;
unsigned long mig_status;
#define NFS_MIG_IN_TRANSITION (1)
#define NFS_MIG_FAILED (2)
NFS: Share NFS superblocks per-protocol per-server per-FSID 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>
2006-08-23 08:06:13 +08:00
void (*destroy)(struct nfs_server *);
atomic_t active; /* Keep trace of any activity to this server */
/* mountd-related mount options */
struct sockaddr_storage mountd_address;
size_t mountd_addrlen;
u32 mountd_version;
unsigned short mountd_port;
unsigned short mountd_protocol;
};
/* Server capabilities */
#define NFS_CAP_READDIRPLUS (1U << 0)
#define NFS_CAP_HARDLINKS (1U << 1)
#define NFS_CAP_SYMLINKS (1U << 2)
#define NFS_CAP_ACLS (1U << 3)
#define NFS_CAP_ATOMIC_OPEN (1U << 4)
#define NFS_CAP_CHANGE_ATTR (1U << 5)
#define NFS_CAP_FILEID (1U << 6)
#define NFS_CAP_MODE (1U << 7)
#define NFS_CAP_NLINK (1U << 8)
#define NFS_CAP_OWNER (1U << 9)
#define NFS_CAP_OWNER_GROUP (1U << 10)
#define NFS_CAP_ATIME (1U << 11)
#define NFS_CAP_CTIME (1U << 12)
#define NFS_CAP_MTIME (1U << 13)
#define NFS_CAP_POSIX_LOCK (1U << 14)
#define NFS_CAP_UIDGID_NOMAP (1U << 15)
#define NFS_CAP_STATEID_NFSV41 (1U << 16)
#define NFS_CAP_ATOMIC_OPEN_V1 (1U << 17)
#define NFS_CAP_SECURITY_LABEL (1U << 18)
#define NFS_CAP_SEEK (1U << 19)
#define NFS_CAP_ALLOCATE (1U << 20)
#define NFS_CAP_DEALLOCATE (1U << 21)
#endif