/* * linux/fs/lockd/svcsubs.c * * Various support routines for the NLM server. * * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> */ #include <linux/types.h> #include <linux/string.h> #include <linux/time.h> #include <linux/in.h> #include <linux/mutex.h> #include <linux/sunrpc/svc.h> #include <linux/sunrpc/clnt.h> #include <linux/nfsd/nfsfh.h> #include <linux/nfsd/export.h> #include <linux/lockd/lockd.h> #include <linux/lockd/share.h> #include <linux/lockd/sm_inter.h> #define NLMDBG_FACILITY NLMDBG_SVCSUBS /* * Global file hash table */ #define FILE_HASH_BITS 7 #define FILE_NRHASH (1<<FILE_HASH_BITS) static struct hlist_head nlm_files[FILE_NRHASH]; static DEFINE_MUTEX(nlm_file_mutex); #ifdef NFSD_DEBUG static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f) { u32 *fhp = (u32*)f->data; /* print the first 32 bytes of the fh */ dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n", msg, fhp[0], fhp[1], fhp[2], fhp[3], fhp[4], fhp[5], fhp[6], fhp[7]); } static inline void nlm_debug_print_file(char *msg, struct nlm_file *file) { struct inode *inode = file->f_file->f_path.dentry->d_inode; dprintk("lockd: %s %s/%ld\n", msg, inode->i_sb->s_id, inode->i_ino); } #else static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f) { return; } static inline void nlm_debug_print_file(char *msg, struct nlm_file *file) { return; } #endif static inline unsigned int file_hash(struct nfs_fh *f) { unsigned int tmp=0; int i; for (i=0; i<NFS2_FHSIZE;i++) tmp += f->data[i]; return tmp & (FILE_NRHASH - 1); } /* * Lookup file info. If it doesn't exist, create a file info struct * and open a (VFS) file for the given inode. * * FIXME: * Note that we open the file O_RDONLY even when creating write locks. * This is not quite right, but for now, we assume the client performs * the proper R/W checking. */ __be32 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result, struct nfs_fh *f) { struct hlist_node *pos; struct nlm_file *file; unsigned int hash; __be32 nfserr; nlm_debug_print_fh("nlm_lookup_file", f); hash = file_hash(f); /* Lock file table */ mutex_lock(&nlm_file_mutex); hlist_for_each_entry(file, pos, &nlm_files[hash], f_list) if (!nfs_compare_fh(&file->f_handle, f)) goto found; nlm_debug_print_fh("creating file for", f); nfserr = nlm_lck_denied_nolocks; file = kzalloc(sizeof(*file), GFP_KERNEL); if (!file) goto out_unlock; memcpy(&file->f_handle, f, sizeof(struct nfs_fh)); mutex_init(&file->f_mutex); INIT_HLIST_NODE(&file->f_list); INIT_LIST_HEAD(&file->f_blocks); /* Open the file. Note that this must not sleep for too long, else * we would lock up lockd:-) So no NFS re-exports, folks. * * We have to make sure we have the right credential to open * the file. */ if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) { dprintk("lockd: open failed (error %d)\n", nfserr); goto out_free; } hlist_add_head(&file->f_list, &nlm_files[hash]); found: dprintk("lockd: found file %p (count %d)\n", file, file->f_count); *result = file; file->f_count++; nfserr = 0; out_unlock: mutex_unlock(&nlm_file_mutex); return nfserr; out_free: kfree(file); goto out_unlock; } /* * Delete a file after having released all locks, blocks and shares */ static inline void nlm_delete_file(struct nlm_file *file) { nlm_debug_print_file("closing file", file); if (!hlist_unhashed(&file->f_list)) { hlist_del(&file->f_list); nlmsvc_ops->fclose(file->f_file); kfree(file); } else { printk(KERN_WARNING "lockd: attempt to release unknown file!\n"); } } /* * Loop over all locks on the given file and perform the specified * action. */ static int nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match) { struct inode *inode = nlmsvc_file_inode(file); struct file_lock *fl; struct nlm_host *lockhost; again: file->f_locks = 0; for (fl = inode->i_flock; fl; fl = fl->fl_next) { if (fl->fl_lmops != &nlmsvc_lock_operations) continue; /* update current lock count */ file->f_locks++; lockhost = (struct nlm_host *) fl->fl_owner; if (match(lockhost, host)) { struct file_lock lock = *fl; lock.fl_type = F_UNLCK; lock.fl_start = 0; lock.fl_end = OFFSET_MAX; if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) { printk("lockd: unlock failure in %s:%d\n", __FILE__, __LINE__); return 1; } goto again; } } return 0; } /* * Inspect a single file */ static inline int nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match) { nlmsvc_traverse_blocks(host, file, match); nlmsvc_traverse_shares(host, file, match); return nlm_traverse_locks(host, file, match); } /* * Quick check whether there are still any locks, blocks or * shares on a given file. */ static inline int nlm_file_inuse(struct nlm_file *file) { struct inode *inode = nlmsvc_file_inode(file); struct file_lock *fl; if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares) return 1; for (fl = inode->i_flock; fl; fl = fl->fl_next) { if (fl->fl_lmops == &nlmsvc_lock_operations) return 1; } file->f_locks = 0; return 0; } /* * Loop over all files in the file table. */ static int nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match) { struct hlist_node *pos, *next; struct nlm_file *file; int i, ret = 0; mutex_lock(&nlm_file_mutex); for (i = 0; i < FILE_NRHASH; i++) { hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) { file->f_count++; mutex_unlock(&nlm_file_mutex); /* Traverse locks, blocks and shares of this file * and update file->f_locks count */ if (nlm_inspect_file(host, file, match)) ret = 1; mutex_lock(&nlm_file_mutex); file->f_count--; /* No more references to this file. Let go of it. */ if (list_empty(&file->f_blocks) && !file->f_locks && !file->f_shares && !file->f_count) { hlist_del(&file->f_list); nlmsvc_ops->fclose(file->f_file); kfree(file); } } } mutex_unlock(&nlm_file_mutex); return ret; } /* * Release file. If there are no more remote locks on this file, * close it and free the handle. * * Note that we can't do proper reference counting without major * contortions because the code in fs/locks.c creates, deletes and * splits locks without notification. Our only way is to walk the * entire lock list each time we remove a lock. */ void nlm_release_file(struct nlm_file *file) { dprintk("lockd: nlm_release_file(%p, ct = %d)\n", file, file->f_count); /* Lock file table */ mutex_lock(&nlm_file_mutex); /* If there are no more locks etc, delete the file */ if (--file->f_count == 0 && !nlm_file_inuse(file)) nlm_delete_file(file); mutex_unlock(&nlm_file_mutex); } /* * Helpers function for resource traversal * * nlmsvc_mark_host: * used by the garbage collector; simply sets h_inuse. * Always returns 0. * * nlmsvc_same_host: * returns 1 iff the two hosts match. Used to release * all resources bound to a specific host. * * nlmsvc_is_client: * returns 1 iff the host is a client. * Used by nlmsvc_invalidate_all */ static int nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy) { host->h_inuse = 1; return 0; } static int nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other) { return host == other; } static int nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy) { if (host->h_server) { /* we are destroying locks even though the client * hasn't asked us too, so don't unmonitor the * client */ if (host->h_nsmhandle) host->h_nsmhandle->sm_sticky = 1; return 1; } else return 0; } /* * Mark all hosts that still hold resources */ void nlmsvc_mark_resources(void) { dprintk("lockd: nlmsvc_mark_resources\n"); nlm_traverse_files(NULL, nlmsvc_mark_host); } /* * Release all resources held by the given client */ void nlmsvc_free_host_resources(struct nlm_host *host) { dprintk("lockd: nlmsvc_free_host_resources\n"); if (nlm_traverse_files(host, nlmsvc_same_host)) { printk(KERN_WARNING "lockd: couldn't remove all locks held by %s\n", host->h_name); BUG(); } } /* * Remove all locks held for clients */ void nlmsvc_invalidate_all(void) { /* Release all locks held by NFS clients. * Previously, the code would call * nlmsvc_free_host_resources for each client in * turn, which is about as inefficient as it gets. * Now we just do it once in nlm_traverse_files. */ nlm_traverse_files(NULL, nlmsvc_is_client); }