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369 lines
8.3 KiB
369 lines
8.3 KiB
/*
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* linux/fs/lockd/svcsubs.c
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*
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* Various support routines for the NLM server.
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*
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* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/time.h>
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#include <linux/in.h>
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#include <linux/mutex.h>
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#include <linux/sunrpc/svc.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/nfsd/nfsfh.h>
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#include <linux/nfsd/export.h>
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#include <linux/lockd/lockd.h>
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#include <linux/lockd/share.h>
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#include <linux/lockd/sm_inter.h>
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#define NLMDBG_FACILITY NLMDBG_SVCSUBS
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/*
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* Global file hash table
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*/
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#define FILE_HASH_BITS 7
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#define FILE_NRHASH (1<<FILE_HASH_BITS)
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static struct hlist_head nlm_files[FILE_NRHASH];
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static DEFINE_MUTEX(nlm_file_mutex);
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#ifdef NFSD_DEBUG
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static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
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{
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u32 *fhp = (u32*)f->data;
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/* print the first 32 bytes of the fh */
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dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n",
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msg, fhp[0], fhp[1], fhp[2], fhp[3],
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fhp[4], fhp[5], fhp[6], fhp[7]);
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}
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static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
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{
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struct inode *inode = file->f_file->f_dentry->d_inode;
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dprintk("lockd: %s %s/%ld\n",
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msg, inode->i_sb->s_id, inode->i_ino);
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}
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#else
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static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f)
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{
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return;
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}
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static inline void nlm_debug_print_file(char *msg, struct nlm_file *file)
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{
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return;
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}
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#endif
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static inline unsigned int file_hash(struct nfs_fh *f)
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{
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unsigned int tmp=0;
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int i;
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for (i=0; i<NFS2_FHSIZE;i++)
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tmp += f->data[i];
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return tmp & (FILE_NRHASH - 1);
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}
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/*
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* Lookup file info. If it doesn't exist, create a file info struct
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* and open a (VFS) file for the given inode.
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*
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* FIXME:
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* Note that we open the file O_RDONLY even when creating write locks.
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* This is not quite right, but for now, we assume the client performs
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* the proper R/W checking.
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*/
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u32
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nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
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struct nfs_fh *f)
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{
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struct hlist_node *pos;
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struct nlm_file *file;
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unsigned int hash;
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u32 nfserr;
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nlm_debug_print_fh("nlm_file_lookup", f);
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hash = file_hash(f);
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/* Lock file table */
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mutex_lock(&nlm_file_mutex);
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hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
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if (!nfs_compare_fh(&file->f_handle, f))
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goto found;
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nlm_debug_print_fh("creating file for", f);
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nfserr = nlm_lck_denied_nolocks;
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file = kzalloc(sizeof(*file), GFP_KERNEL);
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if (!file)
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goto out_unlock;
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memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
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mutex_init(&file->f_mutex);
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INIT_HLIST_NODE(&file->f_list);
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INIT_LIST_HEAD(&file->f_blocks);
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/* Open the file. Note that this must not sleep for too long, else
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* we would lock up lockd:-) So no NFS re-exports, folks.
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*
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* We have to make sure we have the right credential to open
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* the file.
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*/
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if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) {
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dprintk("lockd: open failed (error %d)\n", nfserr);
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goto out_free;
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}
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hlist_add_head(&file->f_list, &nlm_files[hash]);
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found:
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dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
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*result = file;
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file->f_count++;
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nfserr = 0;
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out_unlock:
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mutex_unlock(&nlm_file_mutex);
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return nfserr;
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out_free:
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kfree(file);
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#ifdef CONFIG_LOCKD_V4
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if (nfserr == 1)
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nfserr = nlm4_stale_fh;
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else
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#endif
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nfserr = nlm_lck_denied;
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goto out_unlock;
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}
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/*
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* Delete a file after having released all locks, blocks and shares
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*/
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static inline void
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nlm_delete_file(struct nlm_file *file)
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{
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nlm_debug_print_file("closing file", file);
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if (!hlist_unhashed(&file->f_list)) {
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hlist_del(&file->f_list);
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nlmsvc_ops->fclose(file->f_file);
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kfree(file);
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} else {
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printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
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}
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}
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/*
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* Loop over all locks on the given file and perform the specified
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* action.
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*/
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static int
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nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
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nlm_host_match_fn_t match)
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{
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struct inode *inode = nlmsvc_file_inode(file);
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struct file_lock *fl;
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struct nlm_host *lockhost;
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again:
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file->f_locks = 0;
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for (fl = inode->i_flock; fl; fl = fl->fl_next) {
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if (fl->fl_lmops != &nlmsvc_lock_operations)
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continue;
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/* update current lock count */
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file->f_locks++;
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lockhost = (struct nlm_host *) fl->fl_owner;
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if (match(lockhost, host)) {
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struct file_lock lock = *fl;
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lock.fl_type = F_UNLCK;
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lock.fl_start = 0;
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lock.fl_end = OFFSET_MAX;
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if (posix_lock_file(file->f_file, &lock) < 0) {
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printk("lockd: unlock failure in %s:%d\n",
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__FILE__, __LINE__);
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return 1;
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}
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goto again;
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}
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}
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return 0;
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}
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/*
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* Inspect a single file
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*/
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static inline int
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nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match)
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{
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nlmsvc_traverse_blocks(host, file, match);
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nlmsvc_traverse_shares(host, file, match);
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return nlm_traverse_locks(host, file, match);
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}
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/*
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* Quick check whether there are still any locks, blocks or
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* shares on a given file.
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*/
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static inline int
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nlm_file_inuse(struct nlm_file *file)
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{
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struct inode *inode = nlmsvc_file_inode(file);
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struct file_lock *fl;
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if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
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return 1;
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for (fl = inode->i_flock; fl; fl = fl->fl_next) {
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if (fl->fl_lmops == &nlmsvc_lock_operations)
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return 1;
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}
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file->f_locks = 0;
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return 0;
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}
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/*
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* Loop over all files in the file table.
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*/
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static int
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nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
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{
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struct hlist_node *pos, *next;
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struct nlm_file *file;
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int i, ret = 0;
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mutex_lock(&nlm_file_mutex);
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for (i = 0; i < FILE_NRHASH; i++) {
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hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
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file->f_count++;
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mutex_unlock(&nlm_file_mutex);
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/* Traverse locks, blocks and shares of this file
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* and update file->f_locks count */
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if (nlm_inspect_file(host, file, match))
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ret = 1;
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mutex_lock(&nlm_file_mutex);
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file->f_count--;
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/* No more references to this file. Let go of it. */
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if (list_empty(&file->f_blocks) && !file->f_locks
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&& !file->f_shares && !file->f_count) {
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hlist_del(&file->f_list);
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nlmsvc_ops->fclose(file->f_file);
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kfree(file);
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}
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}
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}
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mutex_unlock(&nlm_file_mutex);
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return ret;
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}
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/*
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* Release file. If there are no more remote locks on this file,
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* close it and free the handle.
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*
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* Note that we can't do proper reference counting without major
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* contortions because the code in fs/locks.c creates, deletes and
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* splits locks without notification. Our only way is to walk the
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* entire lock list each time we remove a lock.
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*/
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void
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nlm_release_file(struct nlm_file *file)
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{
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dprintk("lockd: nlm_release_file(%p, ct = %d)\n",
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file, file->f_count);
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/* Lock file table */
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mutex_lock(&nlm_file_mutex);
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/* If there are no more locks etc, delete the file */
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if (--file->f_count == 0 && !nlm_file_inuse(file))
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nlm_delete_file(file);
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mutex_unlock(&nlm_file_mutex);
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}
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/*
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* Helpers function for resource traversal
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*
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* nlmsvc_mark_host:
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* used by the garbage collector; simply sets h_inuse.
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* Always returns 0.
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*
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* nlmsvc_same_host:
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* returns 1 iff the two hosts match. Used to release
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* all resources bound to a specific host.
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*
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* nlmsvc_is_client:
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* returns 1 iff the host is a client.
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* Used by nlmsvc_invalidate_all
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*/
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static int
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nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
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{
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host->h_inuse = 1;
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return 0;
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}
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static int
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nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
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{
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return host == other;
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}
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static int
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nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
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{
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return host->h_server;
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}
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/*
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* Mark all hosts that still hold resources
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*/
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void
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nlmsvc_mark_resources(void)
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{
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dprintk("lockd: nlmsvc_mark_resources\n");
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nlm_traverse_files(NULL, nlmsvc_mark_host);
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}
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/*
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* Release all resources held by the given client
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*/
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void
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nlmsvc_free_host_resources(struct nlm_host *host)
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{
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dprintk("lockd: nlmsvc_free_host_resources\n");
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if (nlm_traverse_files(host, nlmsvc_same_host)) {
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printk(KERN_WARNING
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"lockd: couldn't remove all locks held by %s\n",
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host->h_name);
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BUG();
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}
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}
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/*
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* Remove all locks held for clients
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*/
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void
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nlmsvc_invalidate_all(void)
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{
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/* Release all locks held by NFS clients.
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* Previously, the code would call
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* nlmsvc_free_host_resources for each client in
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* turn, which is about as inefficient as it gets.
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* Now we just do it once in nlm_traverse_files.
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*/
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nlm_traverse_files(NULL, nlmsvc_is_client);
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}
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