linux/fs/ceph/locks.c
Jeff Layton 130d1f956a locks: ensure that fl_owner is always initialized properly in flock and lease codepaths
Currently, the fl_owner isn't set for flock locks. Some filesystems use
byte-range locks to simulate flock locks and there is a common idiom in
those that does:

    fl->fl_owner = (fl_owner_t)filp;
    fl->fl_start = 0;
    fl->fl_end = OFFSET_MAX;

Since flock locks are generally "owned" by the open file description,
move this into the common flock lock setup code. The fl_start and fl_end
fields are already set appropriately, so remove the unneeded setting of
that in flock ops in those filesystems as well.

Finally, the lease code also sets the fl_owner as if they were owned by
the process and not the open file description. This is incorrect as
leases have the same ownership semantics as flock locks. Set them the
same way. The lease code doesn't actually use the fl_owner value for
anything, so this is more for consistency's sake than a bugfix.

Reported-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> (Staging portion)
Acked-by: J. Bruce Fields <bfields@fieldses.org>
2014-06-02 08:09:29 -04:00

333 lines
8.5 KiB
C

#include <linux/ceph/ceph_debug.h>
#include <linux/file.h>
#include <linux/namei.h>
#include <linux/random.h>
#include "super.h"
#include "mds_client.h"
#include <linux/ceph/pagelist.h>
static u64 lock_secret;
static inline u64 secure_addr(void *addr)
{
u64 v = lock_secret ^ (u64)(unsigned long)addr;
/*
* Set the most significant bit, so that MDS knows the 'owner'
* is sufficient to identify the owner of lock. (old code uses
* both 'owner' and 'pid')
*/
v |= (1ULL << 63);
return v;
}
void __init ceph_flock_init(void)
{
get_random_bytes(&lock_secret, sizeof(lock_secret));
}
/**
* Implement fcntl and flock locking functions.
*/
static int ceph_lock_message(u8 lock_type, u16 operation, struct file *file,
int cmd, u8 wait, struct file_lock *fl)
{
struct inode *inode = file_inode(file);
struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
struct ceph_mds_request *req;
int err;
u64 length = 0;
u64 owner;
req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
if (IS_ERR(req))
return PTR_ERR(req);
req->r_inode = inode;
ihold(inode);
req->r_num_caps = 1;
/* mds requires start and length rather than start and end */
if (LLONG_MAX == fl->fl_end)
length = 0;
else
length = fl->fl_end - fl->fl_start + 1;
owner = secure_addr(fl->fl_owner);
dout("ceph_lock_message: rule: %d, op: %d, owner: %llx, pid: %llu, "
"start: %llu, length: %llu, wait: %d, type: %d", (int)lock_type,
(int)operation, owner, (u64)fl->fl_pid, fl->fl_start, length,
wait, fl->fl_type);
req->r_args.filelock_change.rule = lock_type;
req->r_args.filelock_change.type = cmd;
req->r_args.filelock_change.owner = cpu_to_le64(owner);
req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid);
req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);
req->r_args.filelock_change.length = cpu_to_le64(length);
req->r_args.filelock_change.wait = wait;
err = ceph_mdsc_do_request(mdsc, inode, req);
if (operation == CEPH_MDS_OP_GETFILELOCK) {
fl->fl_pid = le64_to_cpu(req->r_reply_info.filelock_reply->pid);
if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
fl->fl_type = F_RDLCK;
else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
fl->fl_type = F_WRLCK;
else
fl->fl_type = F_UNLCK;
fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start);
length = le64_to_cpu(req->r_reply_info.filelock_reply->start) +
le64_to_cpu(req->r_reply_info.filelock_reply->length);
if (length >= 1)
fl->fl_end = length -1;
else
fl->fl_end = 0;
}
ceph_mdsc_put_request(req);
dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, "
"length: %llu, wait: %d, type: %d, err code %d", (int)lock_type,
(int)operation, (u64)fl->fl_pid, fl->fl_start,
length, wait, fl->fl_type, err);
return err;
}
/**
* Attempt to set an fcntl lock.
* For now, this just goes away to the server. Later it may be more awesome.
*/
int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
{
u8 lock_cmd;
int err;
u8 wait = 0;
u16 op = CEPH_MDS_OP_SETFILELOCK;
if (!(fl->fl_flags & FL_POSIX))
return -ENOLCK;
/* No mandatory locks */
if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
return -ENOLCK;
dout("ceph_lock, fl_owner: %p", fl->fl_owner);
/* set wait bit as appropriate, then make command as Ceph expects it*/
if (IS_GETLK(cmd))
op = CEPH_MDS_OP_GETFILELOCK;
else if (IS_SETLKW(cmd))
wait = 1;
if (F_RDLCK == fl->fl_type)
lock_cmd = CEPH_LOCK_SHARED;
else if (F_WRLCK == fl->fl_type)
lock_cmd = CEPH_LOCK_EXCL;
else
lock_cmd = CEPH_LOCK_UNLOCK;
err = ceph_lock_message(CEPH_LOCK_FCNTL, op, file, lock_cmd, wait, fl);
if (!err) {
if (op != CEPH_MDS_OP_GETFILELOCK) {
dout("mds locked, locking locally");
err = posix_lock_file(file, fl, NULL);
if (err && (CEPH_MDS_OP_SETFILELOCK == op)) {
/* undo! This should only happen if
* the kernel detects local
* deadlock. */
ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
CEPH_LOCK_UNLOCK, 0, fl);
dout("got %d on posix_lock_file, undid lock",
err);
}
}
} else if (err == -ERESTARTSYS) {
dout("undoing lock\n");
ceph_lock_message(CEPH_LOCK_FCNTL, op, file,
CEPH_LOCK_UNLOCK, 0, fl);
}
return err;
}
int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
{
u8 lock_cmd;
int err;
u8 wait = 0;
if (!(fl->fl_flags & FL_FLOCK))
return -ENOLCK;
/* No mandatory locks */
if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK)
return -ENOLCK;
dout("ceph_flock, fl_file: %p", fl->fl_file);
if (IS_SETLKW(cmd))
wait = 1;
if (F_RDLCK == fl->fl_type)
lock_cmd = CEPH_LOCK_SHARED;
else if (F_WRLCK == fl->fl_type)
lock_cmd = CEPH_LOCK_EXCL;
else
lock_cmd = CEPH_LOCK_UNLOCK;
err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
file, lock_cmd, wait, fl);
if (!err) {
err = flock_lock_file_wait(file, fl);
if (err) {
ceph_lock_message(CEPH_LOCK_FLOCK,
CEPH_MDS_OP_SETFILELOCK,
file, CEPH_LOCK_UNLOCK, 0, fl);
dout("got %d on flock_lock_file_wait, undid lock", err);
}
} else if (err == -ERESTARTSYS) {
dout("undoing lock\n");
ceph_lock_message(CEPH_LOCK_FLOCK,
CEPH_MDS_OP_SETFILELOCK,
file, CEPH_LOCK_UNLOCK, 0, fl);
}
return err;
}
/**
* Must be called with lock_flocks() already held. Fills in the passed
* counter variables, so you can prepare pagelist metadata before calling
* ceph_encode_locks.
*/
void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
{
struct file_lock *lock;
*fcntl_count = 0;
*flock_count = 0;
for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
if (lock->fl_flags & FL_POSIX)
++(*fcntl_count);
else if (lock->fl_flags & FL_FLOCK)
++(*flock_count);
}
dout("counted %d flock locks and %d fcntl locks",
*flock_count, *fcntl_count);
}
/**
* Encode the flock and fcntl locks for the given inode into the ceph_filelock
* array. Must be called with inode->i_lock already held.
* If we encounter more of a specific lock type than expected, return -ENOSPC.
*/
int ceph_encode_locks_to_buffer(struct inode *inode,
struct ceph_filelock *flocks,
int num_fcntl_locks, int num_flock_locks)
{
struct file_lock *lock;
int err = 0;
int seen_fcntl = 0;
int seen_flock = 0;
int l = 0;
dout("encoding %d flock and %d fcntl locks", num_flock_locks,
num_fcntl_locks);
for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
if (lock->fl_flags & FL_POSIX) {
++seen_fcntl;
if (seen_fcntl > num_fcntl_locks) {
err = -ENOSPC;
goto fail;
}
err = lock_to_ceph_filelock(lock, &flocks[l]);
if (err)
goto fail;
++l;
}
}
for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) {
if (lock->fl_flags & FL_FLOCK) {
++seen_flock;
if (seen_flock > num_flock_locks) {
err = -ENOSPC;
goto fail;
}
err = lock_to_ceph_filelock(lock, &flocks[l]);
if (err)
goto fail;
++l;
}
}
fail:
return err;
}
/**
* Copy the encoded flock and fcntl locks into the pagelist.
* Format is: #fcntl locks, sequential fcntl locks, #flock locks,
* sequential flock locks.
* Returns zero on success.
*/
int ceph_locks_to_pagelist(struct ceph_filelock *flocks,
struct ceph_pagelist *pagelist,
int num_fcntl_locks, int num_flock_locks)
{
int err = 0;
__le32 nlocks;
nlocks = cpu_to_le32(num_fcntl_locks);
err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
if (err)
goto out_fail;
err = ceph_pagelist_append(pagelist, flocks,
num_fcntl_locks * sizeof(*flocks));
if (err)
goto out_fail;
nlocks = cpu_to_le32(num_flock_locks);
err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
if (err)
goto out_fail;
err = ceph_pagelist_append(pagelist,
&flocks[num_fcntl_locks],
num_flock_locks * sizeof(*flocks));
out_fail:
return err;
}
/*
* Given a pointer to a lock, convert it to a ceph filelock
*/
int lock_to_ceph_filelock(struct file_lock *lock,
struct ceph_filelock *cephlock)
{
int err = 0;
cephlock->start = cpu_to_le64(lock->fl_start);
cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
cephlock->client = cpu_to_le64(0);
cephlock->pid = cpu_to_le64((u64)lock->fl_pid);
cephlock->owner = cpu_to_le64(secure_addr(lock->fl_owner));
switch (lock->fl_type) {
case F_RDLCK:
cephlock->type = CEPH_LOCK_SHARED;
break;
case F_WRLCK:
cephlock->type = CEPH_LOCK_EXCL;
break;
case F_UNLCK:
cephlock->type = CEPH_LOCK_UNLOCK;
break;
default:
dout("Have unknown lock type %d", lock->fl_type);
err = -EINVAL;
}
return err;
}