kernel

linux-6.8.1/fs/ceph/locks.c

@@ -0,0 +1,519 @@
+// 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->fl_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->fl_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->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_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->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);
+	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->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_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->fl_flags;
+	fl->fl_flags |= FL_EXISTS;
+	err = locks_lock_file_wait(file, fl);
+	fl->fl_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->fl_flags & FL_POSIX))
+		return -ENOLCK;
+
+	if (ceph_inode_is_shutdown(inode))
+		return -ESTALE;
+
+	doutc(cl, "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;
+	}
+	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;
+
+	if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK == fl->fl_type) {
+		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->fl_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->fl_flags & FL_FLOCK))
+		return -ENOLCK;
+
+	if (ceph_inode_is_shutdown(inode))
+		return -ESTALE;
+
+	doutc(cl, "fl_file: %p\n", fl->fl_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 (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;
+
+	if (F_UNLCK == fl->fl_type) {
+		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->fl_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);
+		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);
+	}
+	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->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:
+		doutc(cl, "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 = 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);
+	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(inode, 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(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;
+}