// 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/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(src->fl_file); atomic_inc(&ceph_inode(inode)->i_filelock_ref); } static void ceph_fl_release_lock(struct file_lock *fl) { struct inode *inode = file_inode(fl->fl_file); struct ceph_inode_info *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); } } 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_client(inode->i_sb)->mdsc; 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; atomic_inc(&ceph_inode(inode)->i_filelock_ref); } 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->fl_owner); dout("ceph_lock_message: 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->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; if (wait) req->r_wait_for_completion = ceph_lock_wait_for_completion; 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\n", (int)lock_type, (int)operation, (u64)fl->fl_pid, fl->fl_start, length, wait, fl->fl_type, err); return err; } static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc, struct ceph_mds_request *req) { 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; dout("ceph_lock_wait_for_completion: 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; } /** * 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); int err = 0; u16 op = CEPH_MDS_OP_SETFILELOCK; u8 wait = 0; u8 lock_cmd; 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\n", 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; spin_lock(&ci->i_ceph_lock); if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) { err = -EIO; } else if (op == CEPH_MDS_OP_SETFILELOCK) { /* * increasing i_filelock_ref closes race window between * handling request reply and adding file_lock struct to * inode. Otherwise, i_auth_cap may get trimmed in the * window. Caller function will decrease the counter. */ fl->fl_ops = &ceph_fl_lock_ops; atomic_inc(&ci->i_filelock_ref); } spin_unlock(&ci->i_ceph_lock); if (err < 0) { if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK == fl->fl_type) posix_lock_file(file, fl, NULL); return err; } 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, inode, lock_cmd, wait, fl); if (!err) { if (op == CEPH_MDS_OP_SETFILELOCK) { dout("mds locked, 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); dout("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); int err = 0; u8 wait = 0; u8 lock_cmd; if (!(fl->fl_flags & FL_FLOCK)) return -ENOLCK; /* No mandatory locks */ if (fl->fl_type & LOCK_MAND) return -EOPNOTSUPP; dout("ceph_flock, fl_file: %p\n", fl->fl_file); spin_lock(&ci->i_ceph_lock); if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) { err = -EIO; } else { /* see comment in ceph_lock */ fl->fl_ops = &ceph_fl_lock_ops; atomic_inc(&ci->i_filelock_ref); } spin_unlock(&ci->i_ceph_lock); if (err < 0) { if (F_UNLCK == fl->fl_type) locks_lock_file_wait(file, fl); return err; } 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, inode, lock_cmd, wait, fl); if (!err) { 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); dout("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 file_lock *lock; struct file_lock_context *ctx; *fcntl_count = 0; *flock_count = 0; ctx = inode->i_flctx; if (ctx) { spin_lock(&ctx->flc_lock); list_for_each_entry(lock, &ctx->flc_posix, fl_list) ++(*fcntl_count); list_for_each_entry(lock, &ctx->flc_flock, fl_list) ++(*flock_count); spin_unlock(&ctx->flc_lock); } dout("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 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\n", lock->fl_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 = inode->i_flctx; int err = 0; int seen_fcntl = 0; int seen_flock = 0; int l = 0; dout("encoding %d flock and %d fcntl locks\n", num_flock_locks, num_fcntl_locks); if (!ctx) return 0; spin_lock(&ctx->flc_lock); list_for_each_entry(lock, &ctx->flc_posix, fl_list) { ++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; } list_for_each_entry(lock, &ctx->flc_flock, fl_list) { ++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: 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; }