Keep read and write fds with each nlm_file

We shouldn't really be using a read-only file descriptor to take a write
lock.

Most filesystems will put up with it.  But NFS, for example, won't.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
J. Bruce Fields 2021-08-23 16:44:00 -04:00 committed by Chuck Lever
parent b661601a9f
commit 7f024fcd5c
7 changed files with 111 additions and 44 deletions

View File

@ -40,13 +40,15 @@ nlm4svc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
/* Obtain file pointer. Not used by FREE_ALL call. */
if (filp != NULL) {
int mode = lock_to_openmode(&lock->fl);
error = nlm_lookup_file(rqstp, &file, lock);
if (error)
goto no_locks;
*filp = file;
/* Set up the missing parts of the file_lock structure */
lock->fl.fl_file = file->f_file;
lock->fl.fl_file = file->f_file[mode];
lock->fl.fl_pid = current->tgid;
lock->fl.fl_lmops = &nlmsvc_lock_operations;
nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);

View File

@ -471,6 +471,7 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
{
struct nlm_block *block = NULL;
int error;
int mode;
__be32 ret;
dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
@ -524,7 +525,8 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
if (!wait)
lock->fl.fl_flags &= ~FL_SLEEP;
error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
mode = lock_to_openmode(&lock->fl);
error = vfs_lock_file(file->f_file[mode], F_SETLK, &lock->fl, NULL);
lock->fl.fl_flags &= ~FL_SLEEP;
dprintk("lockd: vfs_lock_file returned %d\n", error);
@ -577,6 +579,7 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
struct nlm_lock *conflock, struct nlm_cookie *cookie)
{
int error;
int mode;
__be32 ret;
struct nlm_lockowner *test_owner;
@ -595,7 +598,8 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
/* If there's a conflicting lock, remember to clean up the test lock */
test_owner = (struct nlm_lockowner *)lock->fl.fl_owner;
error = vfs_test_lock(file->f_file, &lock->fl);
mode = lock_to_openmode(&lock->fl);
error = vfs_test_lock(file->f_file[mode], &lock->fl);
if (error) {
/* We can't currently deal with deferred test requests */
if (error == FILE_LOCK_DEFERRED)
@ -641,7 +645,7 @@ out:
__be32
nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
{
int error;
int error = 0;
dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
nlmsvc_file_inode(file)->i_sb->s_id,
@ -654,7 +658,12 @@ nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
nlmsvc_cancel_blocked(net, file, lock);
lock->fl.fl_type = F_UNLCK;
error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
if (file->f_file[O_RDONLY])
error = vfs_lock_file(file->f_file[O_RDONLY], F_SETLK,
&lock->fl, NULL);
if (file->f_file[O_WRONLY])
error = vfs_lock_file(file->f_file[O_WRONLY], F_SETLK,
&lock->fl, NULL);
return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
}
@ -671,6 +680,7 @@ nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *l
{
struct nlm_block *block;
int status = 0;
int mode;
dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
nlmsvc_file_inode(file)->i_sb->s_id,
@ -686,7 +696,8 @@ nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *l
block = nlmsvc_lookup_block(file, lock);
mutex_unlock(&file->f_mutex);
if (block != NULL) {
vfs_cancel_lock(block->b_file->f_file,
mode = lock_to_openmode(&lock->fl);
vfs_cancel_lock(block->b_file->f_file[mode],
&block->b_call->a_args.lock.fl);
status = nlmsvc_unlink_block(block);
nlmsvc_release_block(block);
@ -803,6 +814,7 @@ nlmsvc_grant_blocked(struct nlm_block *block)
{
struct nlm_file *file = block->b_file;
struct nlm_lock *lock = &block->b_call->a_args.lock;
int mode;
int error;
loff_t fl_start, fl_end;
@ -828,7 +840,8 @@ nlmsvc_grant_blocked(struct nlm_block *block)
lock->fl.fl_flags |= FL_SLEEP;
fl_start = lock->fl.fl_start;
fl_end = lock->fl.fl_end;
error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
mode = lock_to_openmode(&lock->fl);
error = vfs_lock_file(file->f_file[mode], F_SETLK, &lock->fl, NULL);
lock->fl.fl_flags &= ~FL_SLEEP;
lock->fl.fl_start = fl_start;
lock->fl.fl_end = fl_end;

View File

@ -55,6 +55,7 @@ nlmsvc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_host *host = NULL;
struct nlm_file *file = NULL;
struct nlm_lock *lock = &argp->lock;
int mode;
__be32 error = 0;
/* nfsd callbacks must have been installed for this procedure */
@ -75,7 +76,8 @@ nlmsvc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
*filp = file;
/* Set up the missing parts of the file_lock structure */
lock->fl.fl_file = file->f_file;
mode = lock_to_openmode(&lock->fl);
lock->fl.fl_file = file->f_file[mode];
lock->fl.fl_pid = current->tgid;
lock->fl.fl_lmops = &nlmsvc_lock_operations;
nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);

View File

@ -71,14 +71,35 @@ static inline unsigned int file_hash(struct nfs_fh *f)
return tmp & (FILE_NRHASH - 1);
}
int lock_to_openmode(struct file_lock *lock)
{
return (lock->fl_type == F_WRLCK) ? O_WRONLY : O_RDONLY;
}
/*
* Open the file. Note that if we're reexporting, for example,
* this could block the lockd thread for a while.
*
* We have to make sure we have the right credential to open
* the file.
*/
static __be32 nlm_do_fopen(struct svc_rqst *rqstp,
struct nlm_file *file, int mode)
{
struct file **fp = &file->f_file[mode];
__be32 nfserr;
if (*fp)
return 0;
nfserr = nlmsvc_ops->fopen(rqstp, &file->f_handle, fp, mode);
if (nfserr)
dprintk("lockd: open failed (error %d)\n", nfserr);
return nfserr;
}
/*
* 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,
@ -87,42 +108,38 @@ nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
struct nlm_file *file;
unsigned int hash;
__be32 nfserr;
int mode;
nlm_debug_print_fh("nlm_lookup_file", &lock->fh);
hash = file_hash(&lock->fh);
mode = lock_to_openmode(&lock->fl);
/* Lock file table */
mutex_lock(&nlm_file_mutex);
hlist_for_each_entry(file, &nlm_files[hash], f_list)
if (!nfs_compare_fh(&file->f_handle, &lock->fh))
if (!nfs_compare_fh(&file->f_handle, &lock->fh)) {
mutex_lock(&file->f_mutex);
nfserr = nlm_do_fopen(rqstp, file, mode);
mutex_unlock(&file->f_mutex);
goto found;
}
nlm_debug_print_fh("creating file for", &lock->fh);
nfserr = nlm_lck_denied_nolocks;
file = kzalloc(sizeof(*file), GFP_KERNEL);
if (!file)
goto out_unlock;
goto out_free;
memcpy(&file->f_handle, &lock->fh, 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 if we're reexporting, for example,
* this could block the lockd thread for a while.
*
* We have to make sure we have the right credential to open
* the file.
*/
nfserr = nlmsvc_ops->fopen(rqstp, &lock->fh, &file->f_file);
if (nfserr) {
dprintk("lockd: open failed (error %d)\n", nfserr);
goto out_free;
}
nfserr = nlm_do_fopen(rqstp, file, mode);
if (nfserr)
goto out_unlock;
hlist_add_head(&file->f_list, &nlm_files[hash]);
@ -130,7 +147,6 @@ 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);
@ -150,13 +166,34 @@ 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);
if (file->f_file[O_RDONLY])
nlmsvc_ops->fclose(file->f_file[O_RDONLY]);
if (file->f_file[O_WRONLY])
nlmsvc_ops->fclose(file->f_file[O_WRONLY]);
kfree(file);
} else {
printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
}
}
static int nlm_unlock_files(struct nlm_file *file)
{
struct file_lock lock;
struct file *f;
lock.fl_type = F_UNLCK;
lock.fl_start = 0;
lock.fl_end = OFFSET_MAX;
for (f = file->f_file[0]; f <= file->f_file[1]; f++) {
if (f && vfs_lock_file(f, F_SETLK, &lock, NULL) < 0) {
pr_warn("lockd: unlock failure in %s:%d\n",
__FILE__, __LINE__);
return 1;
}
}
return 0;
}
/*
* Loop over all locks on the given file and perform the specified
* action.
@ -184,17 +221,10 @@ again:
lockhost = ((struct nlm_lockowner *)fl->fl_owner)->host;
if (match(lockhost, host)) {
struct file_lock lock = *fl;
spin_unlock(&flctx->flc_lock);
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__);
if (nlm_unlock_files(file))
return 1;
}
goto again;
}
}
@ -248,6 +278,15 @@ nlm_file_inuse(struct nlm_file *file)
return 0;
}
static void nlm_close_files(struct nlm_file *file)
{
struct file *f;
for (f = file->f_file[0]; f <= file->f_file[1]; f++)
if (f)
nlmsvc_ops->fclose(f);
}
/*
* Loop over all files in the file table.
*/
@ -278,7 +317,7 @@ nlm_traverse_files(void *data, nlm_host_match_fn_t match,
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);
nlm_close_files(file);
kfree(file);
}
}
@ -412,6 +451,7 @@ nlmsvc_invalidate_all(void)
nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
}
static int
nlmsvc_match_sb(void *datap, struct nlm_file *file)
{

View File

@ -25,9 +25,11 @@
* Note: we hold the dentry use count while the file is open.
*/
static __be32
nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, struct file **filp)
nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, struct file **filp,
int mode)
{
__be32 nfserr;
int access;
struct svc_fh fh;
/* must initialize before using! but maxsize doesn't matter */
@ -36,7 +38,9 @@ nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, struct file **filp)
memcpy((char*)&fh.fh_handle.fh_base, f->data, f->size);
fh.fh_export = NULL;
nfserr = nfsd_open(rqstp, &fh, S_IFREG, NFSD_MAY_LOCK, filp);
access = (mode == O_WRONLY) ? NFSD_MAY_WRITE : NFSD_MAY_READ;
access |= NFSD_MAY_LOCK;
nfserr = nfsd_open(rqstp, &fh, S_IFREG, access, filp);
fh_put(&fh);
/* We return nlm error codes as nlm doesn't know
* about nfsd, but nfsd does know about nlm..

View File

@ -27,7 +27,8 @@ struct rpc_task;
struct nlmsvc_binding {
__be32 (*fopen)(struct svc_rqst *,
struct nfs_fh *,
struct file **);
struct file **,
int mode);
void (*fclose)(struct file *);
};

View File

@ -10,6 +10,8 @@
#ifndef LINUX_LOCKD_LOCKD_H
#define LINUX_LOCKD_LOCKD_H
/* XXX: a lot of this should really be under fs/lockd. */
#include <linux/in.h>
#include <linux/in6.h>
#include <net/ipv6.h>
@ -154,7 +156,8 @@ struct nlm_rqst {
struct nlm_file {
struct hlist_node f_list; /* linked list */
struct nfs_fh f_handle; /* NFS file handle */
struct file * f_file; /* VFS file pointer */
struct file * f_file[2]; /* VFS file pointers,
indexed by O_ flags */
struct nlm_share * f_shares; /* DOS shares */
struct list_head f_blocks; /* blocked locks */
unsigned int f_locks; /* guesstimate # of locks */
@ -267,6 +270,7 @@ typedef int (*nlm_host_match_fn_t)(void *cur, struct nlm_host *ref);
/*
* Server-side lock handling
*/
int lock_to_openmode(struct file_lock *);
__be32 nlmsvc_lock(struct svc_rqst *, struct nlm_file *,
struct nlm_host *, struct nlm_lock *, int,
struct nlm_cookie *, int);
@ -301,7 +305,8 @@ int nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr);
static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
{
return locks_inode(file->f_file);
return locks_inode(file->f_file[O_RDONLY] ?
file->f_file[O_RDONLY] : file->f_file[O_WRONLY]);
}
static inline int __nlm_privileged_request4(const struct sockaddr *sap)