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/*
* linux/fs/lockd/svcsubs.c
*
* Various support routines for the NLM server.
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/in.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 5
#define FILE_NRHASH (1<<FILE_HASH_BITS)
static struct nlm_file * nlm_files[FILE_NRHASH];
static DECLARE_MUTEX(nlm_file_sema);
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.
*/
u32
nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
struct nfs_fh *f)
{
struct nlm_file *file;
unsigned int hash;
u32 nfserr;
u32 *fhp = (u32*)f->data;
dprintk("lockd: nlm_file_lookup(%08x %08x %08x %08x %08x %08x)\n",
fhp[0], fhp[1], fhp[2], fhp[3], fhp[4], fhp[5]);
hash = file_hash(f);
/* Lock file table */
down(&nlm_file_sema);
for (file = nlm_files[hash]; file; file = file->f_next)
if (!memcmp(&file->f_handle, f, sizeof(*f)))
goto found;
dprintk("lockd: creating file for (%08x %08x %08x %08x %08x %08x)\n",
fhp[0], fhp[1], fhp[2], fhp[3], fhp[4], fhp[5]);
nfserr = nlm_lck_denied_nolocks;
file = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL);
if (!file)
goto out_unlock;
memset(file, 0, sizeof(*file));
memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
file->f_hash = hash;
init_MUTEX(&file->f_sema);
/* 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 (nfserr %d)\n", ntohl(nfserr));
goto out_free;
}
file->f_next = nlm_files[hash];
nlm_files[hash] = file;
found:
dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
*result = file;
file->f_count++;
nfserr = 0;
out_unlock:
up(&nlm_file_sema);
return nfserr;
out_free:
kfree(file);
#ifdef CONFIG_LOCKD_V4
if (nfserr == 1)
nfserr = nlm4_stale_fh;
else
#endif
nfserr = nlm_lck_denied;
goto out_unlock;
}
/*
* Delete a file after having released all locks, blocks and shares
*/
static inline void
nlm_delete_file(struct nlm_file *file)
{
struct inode *inode = file->f_file.f_dentry->d_inode;
struct nlm_file **fp, *f;
dprintk("lockd: closing file %s/%ld\n",
kdevname(inode->i_dev), inode->i_ino);
fp = nlm_files + file->f_hash;
while ((f = *fp) != NULL) {
if (f == file) {
*fp = file->f_next;
nlmsvc_ops->fclose(&file->f_file);
kfree(file);
return;
}
fp = &f->f_next;
}
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, int action)
{
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_flags & FL_LOCKD))
continue;
/* update current lock count */
file->f_locks++;
lockhost = (struct nlm_host *) fl->fl_owner;
if (action == NLM_ACT_MARK)
lockhost->h_inuse = 1;
else if (action == NLM_ACT_CHECK)
return 1;
else if (action == NLM_ACT_UNLOCK) {
struct file_lock lock = *fl;
if (host && lockhost != host)
continue;
lock.fl_type = F_UNLCK;
lock.fl_start = 0;
lock.fl_end = OFFSET_MAX;
if (posix_lock_file(&file->f_file, &lock, 0) < 0) {
printk("lockd: unlock failure in %s:%d\n",
__FILE__, __LINE__);
return 1;
}
goto again;
}
}
return 0;
}
/*
* Operate on a single file
*/
static inline int
nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action)
{
if (action == NLM_ACT_CHECK) {
/* Fast path for mark and sweep garbage collection */
if (file->f_count || file->f_blocks || file->f_shares)
return 1;
} else {
if (nlmsvc_traverse_blocks(host, file, action)
|| nlmsvc_traverse_shares(host, file, action))
return 1;
}
return nlm_traverse_locks(host, file, action);
}
/*
* Loop over all files in the file table.
*/
static int
nlm_traverse_files(struct nlm_host *host, int action)
{
struct nlm_file *file, **fp;
int i;
down(&nlm_file_sema);
for (i = 0; i < FILE_NRHASH; i++) {
fp = nlm_files + i;
while ((file = *fp) != NULL) {
/* Traverse locks, blocks and shares of this file
* and update file->f_locks count */
if (nlm_inspect_file(host, file, action)) {
up(&nlm_file_sema);
return 1;
}
/* No more references to this file. Let go of it. */
if (!file->f_blocks && !file->f_locks
&& !file->f_shares && !file->f_count) {
*fp = file->f_next;
nlmsvc_ops->fclose(&file->f_file);
kfree(file);
} else {
fp = &file->f_next;
}
}
}
up(&nlm_file_sema);
return 0;
}
/*
* 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 */
down(&nlm_file_sema);
/* If there are no more locks etc, delete the file */
if(--file->f_count == 0) {
if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK))
nlm_delete_file(file);
}
up(&nlm_file_sema);
}
/*
* Mark all hosts that still hold resources
*/
void
nlmsvc_mark_resources(void)
{
dprintk("lockd: nlmsvc_mark_resources\n");
nlm_traverse_files(NULL, NLM_ACT_MARK);
}
/*
* 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, NLM_ACT_UNLOCK))
printk(KERN_WARNING
"lockd: couldn't remove all locks held by %s",
host->h_name);
}
/*
* Delete a client when the nfsd entry is removed.
*/
void
nlmsvc_invalidate_client(struct svc_client *clnt)
{
struct nlm_host *host;
if ((host = nlm_lookup_host(clnt, NULL, 0, 0)) != NULL) {
dprintk("lockd: invalidating client for %s\n", host->h_name);
nlmsvc_free_host_resources(host);
host->h_expires = 0;
host->h_killed = 1;
nlm_release_host(host);
}
}
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