// SPDX-License-Identifier: GPL-2.0
#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/filelock.h>
#include <linux/ceph/pagelist.h>
static u64 lock_secret;
static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
struct ceph_mds_request *req);
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));
}
static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
{
struct inode *inode = file_inode(dst->c.flc_file);
atomic_inc(&ceph_inode(inode)->i_filelock_ref);
dst->fl_u.ceph.inode = igrab(inode);
}
/*
* Do not use the 'fl->fl_file' in release function, which
* is possibly already released by another thread.
*/
static void ceph_fl_release_lock(struct file_lock *fl)
{
struct inode *inode = fl->fl_u.ceph.inode;
struct ceph_inode_info *ci;
/*
* If inode is NULL it should be a request file_lock,
* nothing we can do.
*/
if (!inode)
return;
ci = ceph_inode(inode);
if (atomic_dec_and_test(&ci->i_filelock_ref)) {
/* clear error when all locks are released */
spin_lock(&ci->i_ceph_lock);
ci->i_ceph_flags &= ~CEPH_I_ERROR_FILELOCK;
spin_unlock(&ci->i_ceph_lock);
}
fl->fl_u.ceph.inode = NULL;
iput(inode);
}
static const struct file_lock_operations ceph_fl_lock_ops = {
.fl_copy_lock = ceph_fl_copy_lock,
.fl_release_private = ceph_fl_release_lock,
};
/*
* Implement fcntl and flock locking functions.
*/
static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode,
int cmd, u8 wait, struct file_lock *fl)
{
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
struct ceph_client *cl = mdsc->fsc->client;
struct ceph_mds_request *req;
int err;
u64 length = 0;
u64 owner;
if (operation == CEPH_MDS_OP_SETFILELOCK) {
/*
* increasing i_filelock_ref closes race window between
* handling request reply and adding file_lock struct to
* inode. Otherwise, auth caps may get trimmed in the
* window. Caller function will decrease the counter.
*/
fl->fl_ops = &ceph_fl_lock_ops;
fl->fl_ops->fl_copy_lock(fl, NULL);
}
if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK)
wait = 0;
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->c.flc_owner);
doutc(cl, "rule: %d, op: %d, owner: %llx, pid: %llu, "
"start: %llu, length: %llu, wait: %d, type: %d\n",
(int)lock_type, (int)operation, owner,
(u64) fl->c.flc_pid,
fl->fl_start, length, wait, fl->c.flc_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->c.flc_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_submit_request(mdsc, inode, req);
if (!err)
err = ceph_mdsc_wait_request(mdsc, req, wait ?
ceph_lock_wait_for_completion : NULL);
if (!err && operation == CEPH_MDS_OP_GETFILELOCK) {
fl->c.flc_pid = -le64_to_cpu(req->r_reply_info.filelock_reply->pid);
if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
fl->c.flc_type = F_RDLCK;
else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
fl->c.flc_type = F_WRLCK;
else
fl->c.flc_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);
doutc(cl, "rule: %d, op: %d, pid: %llu, start: %llu, "
"length: %llu, wait: %d, type: %d, err code %d\n",
(int)lock_type, (int)operation, (u64) fl->c.flc_pid,
fl->fl_start, length, wait, fl->c.flc_type, err);
return err;
}
static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
struct ceph_mds_request *req)
{
struct ceph_client *cl = mdsc->fsc->client;
struct ceph_mds_request *intr_req;
struct inode *inode = req->r_inode;
int err, lock_type;
BUG_ON(req->r_op != CEPH_MDS_OP_SETFILELOCK);
if (req->r_args.filelock_change.rule == CEPH_LOCK_FCNTL)
lock_type = CEPH_LOCK_FCNTL_INTR;
else if (req->r_args.filelock_change.rule == CEPH_LOCK_FLOCK)
lock_type = CEPH_LOCK_FLOCK_INTR;
else
BUG_ON(1);
BUG_ON(req->r_args.filelock_change.type == CEPH_LOCK_UNLOCK);
err = wait_for_completion_interruptible(&req->r_completion);
if (!err)
return 0;
doutc(cl, "request %llu was interrupted\n", req->r_tid);
mutex_lock(&mdsc->mutex);
if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
err = 0;
} else {
/*
* ensure we aren't running concurrently with
* ceph_fill_trace or ceph_readdir_prepopulate, which
* rely on locks (dir mutex) held by our caller.
*/
mutex_lock(&req->r_fill_mutex);
req->r_err = err;
set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
mutex_unlock(&req->r_fill_mutex);
if (!req->r_session) {
// haven't sent the request
err = 0;
}
}
mutex_unlock(&mdsc->mutex);
if (!err)
return 0;
intr_req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETFILELOCK,
USE_AUTH_MDS);
if (IS_ERR(intr_req))
return PTR_ERR(intr_req);
intr_req->r_inode = inode;
ihold(inode);
intr_req->r_num_caps = 1;
intr_req->r_args.filelock_change = req->r_args.filelock_change;
intr_req->r_args.filelock_change.rule = lock_type;
intr_req->r_args.filelock_change.type = CEPH_LOCK_UNLOCK;
err = ceph_mdsc_do_request(mdsc, inode, intr_req);
ceph_mdsc_put_request(intr_req);
if (err && err != -ERESTARTSYS)
return err;
wait_for_completion_killable(&req->r_safe_completion);
return 0;
}
static int try_unlock_file(struct file *file, struct file_lock *fl)
{
int err;
unsigned int orig_flags = fl->c.flc_flags;
fl->c.flc_flags |= FL_EXISTS;
err = locks_lock_file_wait(file, fl);
fl->c.flc_flags = orig_flags;
if (err == -ENOENT) {
if (!(orig_flags & FL_EXISTS))
err = 0;
return err;
}
return 1;
}
/*
* 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)
{
struct inode *inode = file_inode(file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_client *cl = ceph_inode_to_client(inode);
int err = 0;
u16 op = CEPH_MDS_OP_SETFILELOCK;
u8 wait = 0;
u8 lock_cmd;
if (!(fl->c.flc_flags & FL_POSIX))
return -ENOLCK;
if (ceph_inode_is_shutdown(inode))
return -ESTALE;
doutc(cl, "fl_owner: %p\n", fl->c.flc_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;
spin_lock(&ci->i_ceph_lock);
if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) {
err = -EIO;
}
spin_unlock(&ci->i_ceph_lock);
if (err < 0) {
if (op == CEPH_MDS_OP_SETFILELOCK && lock_is_unlock(fl))
posix_lock_file(file, fl, NULL);
return err;
}
if (lock_is_read(fl))
lock_cmd = CEPH_LOCK_SHARED;
else if (lock_is_write(fl))
lock_cmd = CEPH_LOCK_EXCL;
else
lock_cmd = CEPH_LOCK_UNLOCK;
if (op == CEPH_MDS_OP_SETFILELOCK && lock_is_unlock(fl)) {
err = try_unlock_file(file, fl);
if (err <= 0)
return err;
}
err = ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, lock_cmd, wait, fl);
if (!err) {
if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK != fl->c.flc_type) {
doutc(cl, "locking locally\n");
err = posix_lock_file(file, fl, NULL);
if (err) {
/* undo! This should only happen if
* the kernel detects local
* deadlock. */
ceph_lock_message(CEPH_LOCK_FCNTL, op, inode,
CEPH_LOCK_UNLOCK, 0, fl);
doutc(cl, "got %d on posix_lock_file, undid lock\n",
err);
}
}
}
return err;
}
int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
{
struct inode *inode = file_inode(file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_client *cl = ceph_inode_to_client(inode);
int err = 0;
u8 wait = 0;
u8 lock_cmd;
if (!(fl->c.flc_flags & FL_FLOCK))
return -ENOLCK;
if (ceph_inode_is_shutdown(inode))
return -ESTALE;
doutc(cl, "fl_file: %p\n", fl->c.flc_file);
spin_lock(&ci->i_ceph_lock);
if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) {
err = -EIO;
}
spin_unlock(&ci->i_ceph_lock);
if (err < 0) {
if (lock_is_unlock(fl))
locks_lock_file_wait(file, fl);
return err;
}
if (IS_SETLKW(cmd))
wait = 1;
if (lock_is_read(fl))
lock_cmd = CEPH_LOCK_SHARED;
else if (lock_is_write(fl))
lock_cmd = CEPH_LOCK_EXCL;
else
lock_cmd = CEPH_LOCK_UNLOCK;
if (lock_is_unlock(fl)) {
err = try_unlock_file(file, fl);
if (err <= 0)
return err;
}
err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
inode, lock_cmd, wait, fl);
if (!err && F_UNLCK != fl->c.flc_type) {
err = locks_lock_file_wait(file, fl);
if (err) {
ceph_lock_message(CEPH_LOCK_FLOCK,
CEPH_MDS_OP_SETFILELOCK,
inode, CEPH_LOCK_UNLOCK, 0, fl);
doutc(cl, "got %d on locks_lock_file_wait, undid lock\n",
err);
}
}
return err;
}
/*
* 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 ceph_client *cl = ceph_inode_to_client(inode);
struct file_lock *lock;
struct file_lock_context *ctx;
*fcntl_count = 0;
*flock_count = 0;
ctx = locks_inode_context(inode);
if (ctx) {
spin_lock(&ctx->flc_lock);
for_each_file_lock(lock, &ctx->flc_posix)
++(*fcntl_count);
for_each_file_lock(lock, &ctx->flc_flock)
++(*flock_count);
spin_unlock(&ctx->flc_lock);
}
doutc(cl, "counted %d flock locks and %d fcntl locks\n",
*flock_count, *fcntl_count);
}
/*
* Given a pointer to a lock, convert it to a ceph filelock
*/
static int lock_to_ceph_filelock(struct inode *inode,
struct file_lock *lock,
struct ceph_filelock *cephlock)
{
struct ceph_client *cl = ceph_inode_to_client(inode);
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->c.flc_pid);
cephlock->owner = cpu_to_le64(secure_addr(lock->c.flc_owner));
switch (lock->c.flc_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:
doutc(cl, "Have unknown lock type %d\n",
lock->c.flc_type);
err = -EINVAL;
}
return err;
}
/*
* 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;
struct file_lock_context *ctx = locks_inode_context(inode);
struct ceph_client *cl = ceph_inode_to_client(inode);
int err = 0;
int seen_fcntl = 0;
int seen_flock = 0;
int l = 0;
doutc(cl, "encoding %d flock and %d fcntl locks\n", num_flock_locks,
num_fcntl_locks);
if (!ctx)
return 0;
spin_lock(&ctx->flc_lock);
for_each_file_lock(lock, &ctx->flc_posix) {
++seen_fcntl;
if (seen_fcntl > num_fcntl_locks) {
err = -ENOSPC;
goto fail;
}
err = lock_to_ceph_filelock(inode, lock, &flocks[l]);
if (err)
goto fail;
++l;
}
for_each_file_lock(lock, &ctx->flc_flock) {
++seen_flock;
if (seen_flock > num_flock_locks) {
err = -ENOSPC;
goto fail;
}
err = lock_to_ceph_filelock(inode, lock, &flocks[l]);
if (err)
goto fail;
++l;
}
fail:
spin_unlock(&ctx->flc_lock);
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;
if (num_fcntl_locks > 0) {
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;
if (num_flock_locks > 0) {
err = ceph_pagelist_append(pagelist, &flocks[num_fcntl_locks],
num_flock_locks * sizeof(*flocks));
}
out_fail:
return err;
}
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