[lttng-tools.git] / src / common / fd-tracker / inode.c

/*
 * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#include <common/defaults.h>
#include <common/error.h>
#include <common/hashtable/utils.h>
#include <common/macros.h>
#include <common/optional.h>
#include <common/string-utils/format.h>
#include <common/utils.h>
#include <inttypes.h>
#include <lttng/constant.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <urcu.h>
#include <urcu/rculfhash.h>
#include <urcu/ref.h>

#include "inode.h"

struct inode_id {
	dev_t device;
	ino_t inode;
};

struct lttng_inode_registry {
	/* Hashtable of inode_id to lttng_inode. */
	struct cds_lfht *inodes;
};

struct lttng_inode {
	struct inode_id id;
	/* Node in the lttng_inode_registry's ht. */
	struct cds_lfht_node registry_node;
	/* Weak reference to ht containing the node. */
	struct cds_lfht *registry_ht;
	struct urcu_ref ref;
	struct rcu_head rcu_head;
	/* Location from which this file can be opened. */
	struct {
		struct lttng_directory_handle *directory_handle;
		char *path;
	} location;
	/* Unlink the underlying file at the release of the inode. */
	bool unlink_pending;
	LTTNG_OPTIONAL(unsigned int) unlinked_id;
	/* Weak reference. */
	struct lttng_unlinked_file_pool *unlinked_file_pool;
};

struct lttng_unlinked_file_pool {
	struct lttng_directory_handle *unlink_directory_handle;
	char *unlink_directory_path;
	unsigned int file_count;
	unsigned int next_id;
};

static struct {
	pthread_mutex_t lock;
	bool initialized;
	unsigned long value;
} seed = {
		.lock = PTHREAD_MUTEX_INITIALIZER,
};

static unsigned long lttng_inode_id_hash(const struct inode_id *id)
{
	uint64_t device = id->device, inode_no = id->inode;

	return hash_key_u64(&device, seed.value) ^
	       hash_key_u64(&inode_no, seed.value);
}

static int lttng_inode_match(struct cds_lfht_node *node, const void *key)
{
	const struct inode_id *id = key;
	const struct lttng_inode *inode = caa_container_of(
			node, struct lttng_inode, registry_node);

	return inode->id.device == id->device && inode->id.inode == id->inode;
}

static void lttng_inode_free(struct rcu_head *head)
{
	struct lttng_inode *inode =
			caa_container_of(head, struct lttng_inode, rcu_head);

	free(inode);
}

static int lttng_unlinked_file_pool_add_inode(
		struct lttng_unlinked_file_pool *pool,
		struct lttng_inode *inode)
{
	int ret;
	const unsigned int unlinked_id = pool->next_id++;
	char *inode_unlinked_name;
	bool reference_acquired;

	DBG("Adding inode of %s to unlinked file pool as id %u",
			inode->location.path, unlinked_id);
	ret = asprintf(&inode_unlinked_name, "%u", unlinked_id);
	if (ret < 0) {
		ERR("Failed to format unlinked inode name");
		ret = -1;
		goto end;
	}

	if (pool->file_count == 0) {
		DBG("Creating unlinked files directory at %s",
				pool->unlink_directory_path);
		assert(!pool->unlink_directory_handle);
		ret = utils_mkdir(pool->unlink_directory_path,
				S_IRWXU | S_IRWXG, -1, -1);
		if (ret) {
			if (errno == EEXIST) {
				/*
				 * Unexpected (previous crash?), but not an
				 * error.
				 */
				DBG("Unlinked file directory \"%s\" already exists",
						pool->unlink_directory_path);
			} else {
				PERROR("Failed to create unlinked files directory at %s",
						pool->unlink_directory_path);
				goto end;
			}
		}
		pool->unlink_directory_handle = lttng_directory_handle_create(
				pool->unlink_directory_path);
	}

	ret = lttng_directory_handle_rename(inode->location.directory_handle,
			inode->location.path, pool->unlink_directory_handle,
			inode_unlinked_name);
	if (ret) {
		goto end;
	}

	lttng_directory_handle_put(inode->location.directory_handle);
	inode->location.directory_handle = NULL;
	reference_acquired = lttng_directory_handle_get(
			pool->unlink_directory_handle);
	assert(reference_acquired);
	inode->location.directory_handle = pool->unlink_directory_handle;

	free(inode->location.path);
	inode->location.path = inode_unlinked_name;
	inode_unlinked_name = NULL;
	LTTNG_OPTIONAL_SET(&inode->unlinked_id, unlinked_id);
	pool->file_count++;
end:
	free(inode_unlinked_name);
	return ret;
}

static int lttng_unlinked_file_pool_remove_inode(
		struct lttng_unlinked_file_pool *pool,
		struct lttng_inode *inode)
{
	int ret;

	DBG("Removing inode with unlinked id %u from unlinked file pool",
			LTTNG_OPTIONAL_GET(inode->unlinked_id));

	ret = lttng_directory_handle_unlink_file(
			inode->location.directory_handle, inode->location.path);
	if (ret) {
		PERROR("Failed to unlink file %s from unlinked file directory",
				inode->location.path);
		goto end;
	}
	free(inode->location.path);
	inode->location.path = NULL;
	lttng_directory_handle_put(inode->location.directory_handle);
	inode->location.directory_handle = NULL;

	pool->file_count--;
	if (pool->file_count == 0) {
		ret = utils_recursive_rmdir(pool->unlink_directory_path);
		if (ret) {
			/*
			 * There is nothing the caller can do, don't report an
			 * error except through logging.
			 */
			PERROR("Failed to remove unlinked files directory at %s",
					pool->unlink_directory_path);
		}
		lttng_directory_handle_put(pool->unlink_directory_handle);
		pool->unlink_directory_handle = NULL;
	}
end:
	return ret;
}

static void lttng_inode_destroy(struct lttng_inode *inode)
{
	if (!inode) {
		return;
	}

	rcu_read_lock();
	cds_lfht_del(inode->registry_ht, &inode->registry_node);
	rcu_read_unlock();

	if (inode->unlink_pending) {
		int ret;

		assert(inode->location.directory_handle);
		assert(inode->location.path);
		DBG("Removing %s from unlinked file pool",
				inode->location.path);
		ret = lttng_unlinked_file_pool_remove_inode(inode->unlinked_file_pool, inode);
		if (ret) {
			PERROR("Failed to unlink %s", inode->location.path);
		}
	}

	lttng_directory_handle_put(
			inode->location.directory_handle);
	inode->location.directory_handle = NULL;
	free(inode->location.path);
	inode->location.path = NULL;
	call_rcu(&inode->rcu_head, lttng_inode_free);
}

static void lttng_inode_release(struct urcu_ref *ref)
{
	lttng_inode_destroy(caa_container_of(ref, struct lttng_inode, ref));
}

static void lttng_inode_get(struct lttng_inode *inode)
{
	urcu_ref_get(&inode->ref);
}

struct lttng_unlinked_file_pool *lttng_unlinked_file_pool_create(
		const char *path)
{
	struct lttng_unlinked_file_pool *pool = zmalloc(sizeof(*pool));

	if (!path || *path != '/') {
		ERR("Unlinked file pool must be created with an absolute path, path = \"%s\"",
				path ? path : "NULL");
		goto error;
	}

	pool->unlink_directory_path = strdup(path);
	if (!pool->unlink_directory_path) {
		PERROR("Failed to allocation unlinked file pool path");
		goto error;
	}
	DBG("Unlinked file pool created at: %s", path);
	return pool;
error:
	lttng_unlinked_file_pool_destroy(pool);
	return NULL;
}

void lttng_unlinked_file_pool_destroy(
		struct lttng_unlinked_file_pool *pool)
{
	if (!pool) {
		return;
	}

	assert(pool->file_count == 0);
	lttng_directory_handle_put(pool->unlink_directory_handle);
	free(pool->unlink_directory_path);
	free(pool);
}

void lttng_inode_put(struct lttng_inode *inode)
{
	urcu_ref_put(&inode->ref, lttng_inode_release);
}

struct lttng_directory_handle *lttng_inode_get_location_directory_handle(
		struct lttng_inode *inode)
{
	if (inode->location.directory_handle) {
		const bool reference_acquired = lttng_directory_handle_get(
				inode->location.directory_handle);

		assert(reference_acquired);
	}
	return inode->location.directory_handle;
}

void lttng_inode_borrow_location(struct lttng_inode *inode,
		const struct lttng_directory_handle **out_directory_handle,
		const char **out_path)
{
	if (out_directory_handle) {
		*out_directory_handle = inode->location.directory_handle;
	}
	if (out_path) {
		*out_path = inode->location.path;
	}
}

int lttng_inode_rename(
		struct lttng_inode *inode,
		struct lttng_directory_handle *old_directory_handle,
		const char *old_path,
		struct lttng_directory_handle *new_directory_handle,
		const char *new_path,
		bool overwrite)
{
	int ret = 0;
	char *new_path_copy = strdup(new_path);
	bool reference_acquired;

	DBG("Performing rename of inode from %s to %s with %s directory handles",
			old_path, new_path,
			lttng_directory_handle_equals(old_directory_handle,
					new_directory_handle) ?
					"identical" :
					"different");

	if (!new_path_copy) {
		ret = -ENOMEM;
		goto end;
	}

	if (inode->unlink_pending) {
		WARN("An attempt to rename an unlinked file from %s to %s has been performed",
				old_path, new_path);
		ret = -ENOENT;
		goto end;
	}

	if (!overwrite) {
		/* Verify that file doesn't exist. */
		struct stat statbuf;

		ret = lttng_directory_handle_stat(
				new_directory_handle, new_path, &statbuf);
		if (ret == 0) {
			ERR("Refusing to rename %s as the destination already exists",
					old_path);
			ret = -EEXIST;
			goto end;
		} else if (ret < 0 && errno != ENOENT) {
			PERROR("Failed to stat() %s", new_path);
			ret = -errno;
			goto end;
		}
	}

	ret = lttng_directory_handle_rename(old_directory_handle, old_path,
			new_directory_handle, new_path);
	if (ret) {
		PERROR("Failed to rename file %s to %s", old_path, new_path);
		ret = -errno;
		goto end;
	}

	reference_acquired = lttng_directory_handle_get(new_directory_handle);
	assert(reference_acquired);
	lttng_directory_handle_put(inode->location.directory_handle);
	free(inode->location.path);
	inode->location.directory_handle = new_directory_handle;
	/* Ownership transferred. */
	inode->location.path = new_path_copy;
	new_path_copy = NULL;
end:
	free(new_path_copy);
	return ret;
}

int lttng_inode_unlink(struct lttng_inode *inode)
{
	int ret = 0;

	DBG("Attempting unlink of inode %s", inode->location.path);

	if (inode->unlink_pending) {
		WARN("An attempt to re-unlink %s has been performed, ignoring.",
				inode->location.path);
		ret = -ENOENT;
		goto end;
	}

	/*
	 * Move to the temporary "deleted" directory until all
	 * references are released.
	 */
	ret = lttng_unlinked_file_pool_add_inode(
			inode->unlinked_file_pool, inode);
	if (ret) {
		PERROR("Failed to add inode \"%s\" to the unlinked file pool",
				inode->location.path);
		goto end;
	}
	inode->unlink_pending = true;
end:
	return ret;
}

static struct lttng_inode *lttng_inode_create(const struct inode_id *id,
		struct cds_lfht *ht,
		struct lttng_unlinked_file_pool *unlinked_file_pool,
		struct lttng_directory_handle *directory_handle,
		const char *path)
{
	struct lttng_inode *inode = NULL;
	char *path_copy;
	bool reference_acquired;

	path_copy = strdup(path);
	if (!path_copy) {
		goto end;
	}

	reference_acquired = lttng_directory_handle_get(directory_handle);
	assert(reference_acquired);

	inode = zmalloc(sizeof(*inode));
	if (!inode) {
		goto end;
	}

	urcu_ref_init(&inode->ref);
	cds_lfht_node_init(&inode->registry_node);
	inode->id = *id;
	inode->registry_ht = ht;
	inode->unlinked_file_pool = unlinked_file_pool;
	/* Ownership of path copy is transferred to inode. */
	inode->location.path = path_copy;
	path_copy = NULL;
	inode->location.directory_handle = directory_handle;
end:
	free(path_copy);
	return inode;
}

struct lttng_inode_registry *lttng_inode_registry_create(void)
{
	struct lttng_inode_registry *registry = zmalloc(sizeof(*registry));

	if (!registry) {
		goto end;
	}

	pthread_mutex_lock(&seed.lock);
	if (!seed.initialized) {
		seed.value = (unsigned long) time(NULL);
		seed.initialized = true;
	}
	pthread_mutex_unlock(&seed.lock);

	registry->inodes = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
			CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
	if (!registry->inodes) {
		goto error;
	}
end:
	return registry;
error:
	lttng_inode_registry_destroy(registry);
	return NULL;
}

void lttng_inode_registry_destroy(struct lttng_inode_registry *registry)
{
	if (!registry) {
		return;
	}
	if (registry->inodes) {
		int ret = cds_lfht_destroy(registry->inodes, NULL);

		assert(!ret);
	}
	free(registry);
}

struct lttng_inode *lttng_inode_registry_get_inode(
		struct lttng_inode_registry *registry,
		struct lttng_directory_handle *handle,
		const char *path,
		int fd,
		struct lttng_unlinked_file_pool *unlinked_file_pool)
{
	int ret;
	struct stat statbuf;
	struct inode_id id;
	struct cds_lfht_iter iter;
	struct cds_lfht_node *node;
	struct lttng_inode *inode = NULL;

	ret = fstat(fd, &statbuf);
	if (ret < 0) {
		PERROR("stat() failed on fd %i", fd);
		goto end;
	}

	id.device = statbuf.st_dev;
	id.inode = statbuf.st_ino;

	rcu_read_lock();
	cds_lfht_lookup(registry->inodes, lttng_inode_id_hash(&id),
			lttng_inode_match, &id, &iter);
	node = cds_lfht_iter_get_node(&iter);
	if (node) {
		inode = caa_container_of(
				node, struct lttng_inode, registry_node);
		lttng_inode_get(inode);
		goto end_unlock;
	}

	inode = lttng_inode_create(&id, registry->inodes, unlinked_file_pool,
			handle, path);
	node = cds_lfht_add_unique(registry->inodes,
			lttng_inode_id_hash(&inode->id), lttng_inode_match,
			&inode->id, &inode->registry_node);
	assert(node == &inode->registry_node);
end_unlock:
	rcu_read_unlock();
end:
	return inode;
}
Commit	Line	Data
e0e72660	1	/*
ab5be9fa	2	* Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
e0e72660	3	*
ab5be9fa	4	* SPDX-License-Identifier: GPL-2.0-only
e0e72660	5	*
e0e72660 JG	6	*/
e0e72660 JG	7
5c1f54d1 JG	8	#include <common/defaults.h>
	9	#include <common/error.h>
	10	#include <common/hashtable/utils.h>
	11	#include <common/macros.h>
f7c3ffd7 JG	12	#include <common/optional.h>
	13	#include <common/string-utils/format.h>
	14	#include <common/utils.h>
5c1f54d1 JG	15	#include <inttypes.h>
5c1f54d1 JG	16	#include <lttng/constant.h>
e0e72660	17	#include <sys/stat.h>
5c1f54d1	18	#include <sys/types.h>
e0e72660	19	#include <unistd.h>
e0e72660	20	#include <urcu.h>
e0e72660	21	#include <urcu/rculfhash.h>
5c1f54d1	22	#include <urcu/ref.h>
e0e72660 JG	23
	24	#include "inode.h"
	25
	26	struct inode_id {
	27	dev_t device;
	28	ino_t inode;
	29	};
	30
	31	struct lttng_inode_registry {
	32	/* Hashtable of inode_id to lttng_inode. */
	33	struct cds_lfht *inodes;
	34	};
	35
	36	struct lttng_inode {
	37	struct inode_id id;
e0e72660 JG	38	/* Node in the lttng_inode_registry's ht. */
	39	struct cds_lfht_node registry_node;
	40	/* Weak reference to ht containing the node. */
	41	struct cds_lfht *registry_ht;
	42	struct urcu_ref ref;
	43	struct rcu_head rcu_head;
f7c3ffd7 JG	44	/* Location from which this file can be opened. */
	45	struct {
	46	struct lttng_directory_handle *directory_handle;
	47	char *path;
	48	} location;
	49	/* Unlink the underlying file at the release of the inode. */
	50	bool unlink_pending;
	51	LTTNG_OPTIONAL(unsigned int) unlinked_id;
	52	/* Weak reference. */
	53	struct lttng_unlinked_file_pool *unlinked_file_pool;
	54	};
	55
	56	struct lttng_unlinked_file_pool {
	57	struct lttng_directory_handle *unlink_directory_handle;
	58	char *unlink_directory_path;
	59	unsigned int file_count;
	60	unsigned int next_id;
e0e72660 JG	61	};
	62
	63	static struct {
	64	pthread_mutex_t lock;
	65	bool initialized;
	66	unsigned long value;
	67	} seed = {
5c1f54d1	68	.lock = PTHREAD_MUTEX_INITIALIZER,
e0e72660 JG	69	};
e0e72660 JG	70
f7c3ffd7	71	static unsigned long lttng_inode_id_hash(const struct inode_id *id)
e0e72660 JG	72	{
	73	uint64_t device = id->device, inode_no = id->inode;
	74
5c1f54d1 JG	75	return hash_key_u64(&device, seed.value) ^
5c1f54d1 JG	76	hash_key_u64(&inode_no, seed.value);
e0e72660 JG	77	}
e0e72660 JG	78
5c1f54d1	79	static int lttng_inode_match(struct cds_lfht_node node, const void key)
e0e72660 JG	80	{
e0e72660 JG	81	const struct inode_id *id = key;
f7c3ffd7	82	const struct lttng_inode *inode = caa_container_of(
5c1f54d1	83	node, struct lttng_inode, registry_node);
e0e72660 JG	84
	85	return inode->id.device == id->device && inode->id.inode == id->inode;
	86	}
	87
f7c3ffd7	88	static void lttng_inode_free(struct rcu_head *head)
e0e72660	89	{
5c1f54d1 JG	90	struct lttng_inode *inode =
5c1f54d1 JG	91	caa_container_of(head, struct lttng_inode, rcu_head);
e0e72660	92
e0e72660 JG	93	free(inode);
	94	}
	95
f7c3ffd7 JG	96	static int lttng_unlinked_file_pool_add_inode(
	97	struct lttng_unlinked_file_pool *pool,
	98	struct lttng_inode *inode)
	99	{
	100	int ret;
	101	const unsigned int unlinked_id = pool->next_id++;
	102	char *inode_unlinked_name;
	103	bool reference_acquired;
	104
	105	DBG("Adding inode of %s to unlinked file pool as id %u",
	106	inode->location.path, unlinked_id);
	107	ret = asprintf(&inode_unlinked_name, "%u", unlinked_id);
	108	if (ret < 0) {
	109	ERR("Failed to format unlinked inode name");
	110	ret = -1;
	111	goto end;
	112	}
	113
	114	if (pool->file_count == 0) {
	115	DBG("Creating unlinked files directory at %s",
	116	pool->unlink_directory_path);
	117	assert(!pool->unlink_directory_handle);
	118	ret = utils_mkdir(pool->unlink_directory_path,
	119	S_IRWXU \| S_IRWXG, -1, -1);
	120	if (ret) {
	121	if (errno == EEXIST) {
	122	/*
	123	* Unexpected (previous crash?), but not an
	124	* error.
	125	*/
	126	DBG("Unlinked file directory \"%s\" already exists",
	127	pool->unlink_directory_path);
	128	} else {
	129	PERROR("Failed to create unlinked files directory at %s",
	130	pool->unlink_directory_path);
	131	goto end;
	132	}
	133	}
	134	pool->unlink_directory_handle = lttng_directory_handle_create(
	135	pool->unlink_directory_path);
	136	}
	137
	138	ret = lttng_directory_handle_rename(inode->location.directory_handle,
	139	inode->location.path, pool->unlink_directory_handle,
	140	inode_unlinked_name);
	141	if (ret) {
	142	goto end;
	143	}
	144
	145	lttng_directory_handle_put(inode->location.directory_handle);
	146	inode->location.directory_handle = NULL;
	147	reference_acquired = lttng_directory_handle_get(
	148	pool->unlink_directory_handle);
	149	assert(reference_acquired);
	150	inode->location.directory_handle = pool->unlink_directory_handle;
	151
	152	free(inode->location.path);
	153	inode->location.path = inode_unlinked_name;
	154	inode_unlinked_name = NULL;
	155	LTTNG_OPTIONAL_SET(&inode->unlinked_id, unlinked_id);
	156	pool->file_count++;
	157	end:
	158	free(inode_unlinked_name);
	159	return ret;
160	}
161
162	static int lttng_unlinked_file_pool_remove_inode(
163	struct lttng_unlinked_file_pool *pool,
164	struct lttng_inode *inode)
165	{
166	int ret;
167
168	DBG("Removing inode with unlinked id %u from unlinked file pool",
169	LTTNG_OPTIONAL_GET(inode->unlinked_id));
170
171	ret = lttng_directory_handle_unlink_file(
172	inode->location.directory_handle, inode->location.path);
173	if (ret) {
174	PERROR("Failed to unlink file %s from unlinked file directory",
175	inode->location.path);
176	goto end;
177	}
178	free(inode->location.path);
179	inode->location.path = NULL;
180	lttng_directory_handle_put(inode->location.directory_handle);
181	inode->location.directory_handle = NULL;
182
183	pool->file_count--;
184	if (pool->file_count == 0) {
185	ret = utils_recursive_rmdir(pool->unlink_directory_path);
186	if (ret) {
187	/*
188	* There is nothing the caller can do, don't report an
189	* error except through logging.
190	*/
191	PERROR("Failed to remove unlinked files directory at %s",
192	pool->unlink_directory_path);
193	}
194	lttng_directory_handle_put(pool->unlink_directory_handle);
195	pool->unlink_directory_handle = NULL;
196	}
197	end:
198	return ret;
199	}
200
5c1f54d1	201	static void lttng_inode_destroy(struct lttng_inode *inode)
e0e72660 JG	202	{
	203	if (!inode) {
	204	return;
	205	}
f7c3ffd7 JG	206
	207	rcu_read_lock();
	208	cds_lfht_del(inode->registry_ht, &inode->registry_node);
	209	rcu_read_unlock();
	210
e0e72660	211	if (inode->unlink_pending) {
f7c3ffd7	212	int ret;
e0e72660	213
f7c3ffd7 JG	214	assert(inode->location.directory_handle);
	215	assert(inode->location.path);
	216	DBG("Removing %s from unlinked file pool",
	217	inode->location.path);
	218	ret = lttng_unlinked_file_pool_remove_inode(inode->unlinked_file_pool, inode);
e0e72660	219	if (ret) {
f7c3ffd7	220	PERROR("Failed to unlink %s", inode->location.path);
e0e72660 JG	221	}
e0e72660 JG	222	}
f7c3ffd7 JG	223
	224	lttng_directory_handle_put(
	225	inode->location.directory_handle);
	226	inode->location.directory_handle = NULL;
	227	free(inode->location.path);
	228	inode->location.path = NULL;
	229	call_rcu(&inode->rcu_head, lttng_inode_free);
e0e72660 JG	230	}
e0e72660 JG	231
5c1f54d1	232	static void lttng_inode_release(struct urcu_ref *ref)
e0e72660	233	{
5c1f54d1	234	lttng_inode_destroy(caa_container_of(ref, struct lttng_inode, ref));
e0e72660 JG	235	}
e0e72660 JG	236
5c1f54d1	237	static void lttng_inode_get(struct lttng_inode *inode)
e0e72660 JG	238	{
	239	urcu_ref_get(&inode->ref);
	240	}
	241
f7c3ffd7 JG	242	struct lttng_unlinked_file_pool *lttng_unlinked_file_pool_create(
	243	const char *path)
	244	{
	245	struct lttng_unlinked_file_pool pool = zmalloc(sizeof(pool));
	246
	247	if (!path \|\| *path != '/') {
	248	ERR("Unlinked file pool must be created with an absolute path, path = \"%s\"",
	249	path ? path : "NULL");
	250	goto error;
	251	}
	252
	253	pool->unlink_directory_path = strdup(path);
	254	if (!pool->unlink_directory_path) {
	255	PERROR("Failed to allocation unlinked file pool path");
	256	goto error;
	257	}
	258	DBG("Unlinked file pool created at: %s", path);
	259	return pool;
	260	error:
	261	lttng_unlinked_file_pool_destroy(pool);
	262	return NULL;
	263	}
	264
	265	void lttng_unlinked_file_pool_destroy(
	266	struct lttng_unlinked_file_pool *pool)
	267	{
	268	if (!pool) {
	269	return;
	270	}
	271
	272	assert(pool->file_count == 0);
	273	lttng_directory_handle_put(pool->unlink_directory_handle);
	274	free(pool->unlink_directory_path);
	275	free(pool);
	276	}
	277
e0e72660 JG	278	void lttng_inode_put(struct lttng_inode *inode)
	279	{
	280	urcu_ref_put(&inode->ref, lttng_inode_release);
	281	}
	282
dd95933f JG	283	struct lttng_directory_handle *lttng_inode_get_location_directory_handle(
	284	struct lttng_inode *inode)
	285	{
	286	if (inode->location.directory_handle) {
	287	const bool reference_acquired = lttng_directory_handle_get(
	288	inode->location.directory_handle);
	289
	290	assert(reference_acquired);
	291	}
	292	return inode->location.directory_handle;
	293	}
	294
	295	void lttng_inode_borrow_location(struct lttng_inode *inode,
f7c3ffd7 JG	296	const struct lttng_directory_handle **out_directory_handle,
f7c3ffd7 JG	297	const char **out_path)
e0e72660	298	{
f7c3ffd7 JG	299	if (out_directory_handle) {
	300	*out_directory_handle = inode->location.directory_handle;
	301	}
	302	if (out_path) {
	303	*out_path = inode->location.path;
	304	}
e0e72660 JG	305	}
e0e72660 JG	306
5c1f54d1	307	int lttng_inode_rename(
f7c3ffd7 JG	308	struct lttng_inode *inode,
	309	struct lttng_directory_handle *old_directory_handle,
	310	const char *old_path,
	311	struct lttng_directory_handle *new_directory_handle,
	312	const char *new_path,
	313	bool overwrite)
e0e72660 JG	314	{
e0e72660 JG	315	int ret = 0;
f7c3ffd7 JG	316	char *new_path_copy = strdup(new_path);
	317	bool reference_acquired;
	318
	319	DBG("Performing rename of inode from %s to %s with %s directory handles",
	320	old_path, new_path,
	321	lttng_directory_handle_equals(old_directory_handle,
	322	new_directory_handle) ?
	323	"identical" :
	324	"different");
	325
	326	if (!new_path_copy) {
	327	ret = -ENOMEM;
	328	goto end;
	329	}
e0e72660 JG	330
e0e72660 JG	331	if (inode->unlink_pending) {
f7c3ffd7 JG	332	WARN("An attempt to rename an unlinked file from %s to %s has been performed",
f7c3ffd7 JG	333	old_path, new_path);
e0e72660 JG	334	ret = -ENOENT;
	335	goto end;
	336	}
	337
	338	if (!overwrite) {
f7c3ffd7	339	/* Verify that file doesn't exist. */
e0e72660 JG	340	struct stat statbuf;
e0e72660 JG	341
f7c3ffd7 JG	342	ret = lttng_directory_handle_stat(
f7c3ffd7 JG	343	new_directory_handle, new_path, &statbuf);
e0e72660	344	if (ret == 0) {
f7c3ffd7 JG	345	ERR("Refusing to rename %s as the destination already exists",
f7c3ffd7 JG	346	old_path);
e0e72660 JG	347	ret = -EEXIST;
	348	goto end;
	349	} else if (ret < 0 && errno != ENOENT) {
	350	PERROR("Failed to stat() %s", new_path);
	351	ret = -errno;
	352	goto end;
	353	}
	354	}
	355
f7c3ffd7 JG	356	ret = lttng_directory_handle_rename(old_directory_handle, old_path,
f7c3ffd7 JG	357	new_directory_handle, new_path);
e0e72660	358	if (ret) {
f7c3ffd7	359	PERROR("Failed to rename file %s to %s", old_path, new_path);
e0e72660 JG	360	ret = -errno;
	361	goto end;
	362	}
	363
f7c3ffd7 JG	364	reference_acquired = lttng_directory_handle_get(new_directory_handle);
	365	assert(reference_acquired);
	366	lttng_directory_handle_put(inode->location.directory_handle);
	367	free(inode->location.path);
	368	inode->location.directory_handle = new_directory_handle;
	369	/* Ownership transferred. */
	370	inode->location.path = new_path_copy;
e0e72660 JG	371	new_path_copy = NULL;
	372	end:
	373	free(new_path_copy);
	374	return ret;
	375	}
	376
f7c3ffd7	377	int lttng_inode_unlink(struct lttng_inode *inode)
e0e72660 JG	378	{
e0e72660 JG	379	int ret = 0;
f7c3ffd7 JG	380
f7c3ffd7 JG	381	DBG("Attempting unlink of inode %s", inode->location.path);
e0e72660 JG	382
	383	if (inode->unlink_pending) {
	384	WARN("An attempt to re-unlink %s has been performed, ignoring.",
f7c3ffd7	385	inode->location.path);
e0e72660 JG	386	ret = -ENOENT;
	387	goto end;
	388	}
	389
f7c3ffd7 JG	390	/*
	391	* Move to the temporary "deleted" directory until all
	392	* references are released.
	393	*/
	394	ret = lttng_unlinked_file_pool_add_inode(
	395	inode->unlinked_file_pool, inode);
	396	if (ret) {
	397	PERROR("Failed to add inode \"%s\" to the unlinked file pool",
	398	inode->location.path);
e0e72660 JG	399	goto end;
e0e72660 JG	400	}
f7c3ffd7	401	inode->unlink_pending = true;
e0e72660 JG	402	end:
	403	return ret;
	404	}
	405
5c1f54d1	406	static struct lttng_inode lttng_inode_create(const struct inode_id id,
f7c3ffd7 JG	407	struct cds_lfht *ht,
	408	struct lttng_unlinked_file_pool *unlinked_file_pool,
	409	struct lttng_directory_handle *directory_handle,
	410	const char *path)
e0e72660	411	{
f7c3ffd7 JG	412	struct lttng_inode *inode = NULL;
	413	char *path_copy;
	414	bool reference_acquired;
	415
	416	path_copy = strdup(path);
	417	if (!path_copy) {
	418	goto end;
	419	}
e0e72660	420
f7c3ffd7 JG	421	reference_acquired = lttng_directory_handle_get(directory_handle);
	422	assert(reference_acquired);
	423
	424	inode = zmalloc(sizeof(*inode));
e0e72660 JG	425	if (!inode) {
	426	goto end;
	427	}
	428
	429	urcu_ref_init(&inode->ref);
	430	cds_lfht_node_init(&inode->registry_node);
	431	inode->id = *id;
e0e72660	432	inode->registry_ht = ht;
f7c3ffd7 JG	433	inode->unlinked_file_pool = unlinked_file_pool;
	434	/* Ownership of path copy is transferred to inode. */
	435	inode->location.path = path_copy;
	436	path_copy = NULL;
	437	inode->location.directory_handle = directory_handle;
e0e72660	438	end:
f7c3ffd7	439	free(path_copy);
e0e72660	440	return inode;
e0e72660 JG	441	}
	442
	443	struct lttng_inode_registry *lttng_inode_registry_create(void)
	444	{
	445	struct lttng_inode_registry registry = zmalloc(sizeof(registry));
	446
	447	if (!registry) {
	448	goto end;
	449	}
	450
	451	pthread_mutex_lock(&seed.lock);
	452	if (!seed.initialized) {
	453	seed.value = (unsigned long) time(NULL);
	454	seed.initialized = true;
	455	}
	456	pthread_mutex_unlock(&seed.lock);
	457
	458	registry->inodes = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
	459	CDS_LFHT_AUTO_RESIZE \| CDS_LFHT_ACCOUNTING, NULL);
	460	if (!registry->inodes) {
	461	goto error;
	462	}
	463	end:
	464	return registry;
	465	error:
	466	lttng_inode_registry_destroy(registry);
	467	return NULL;
	468	}
	469
	470	void lttng_inode_registry_destroy(struct lttng_inode_registry *registry)
	471	{
	472	if (!registry) {
	473	return;
	474	}
	475	if (registry->inodes) {
	476	int ret = cds_lfht_destroy(registry->inodes, NULL);
	477
	478	assert(!ret);
	479	}
	480	free(registry);
	481	}
	482
	483	struct lttng_inode *lttng_inode_registry_get_inode(
f7c3ffd7 JG	484	struct lttng_inode_registry *registry,
	485	struct lttng_directory_handle *handle,
	486	const char *path,
	487	int fd,
	488	struct lttng_unlinked_file_pool *unlinked_file_pool)
e0e72660 JG	489	{
	490	int ret;
	491	struct stat statbuf;
	492	struct inode_id id;
	493	struct cds_lfht_iter iter;
	494	struct cds_lfht_node *node;
	495	struct lttng_inode *inode = NULL;
	496
	497	ret = fstat(fd, &statbuf);
	498	if (ret < 0) {
f7c3ffd7	499	PERROR("stat() failed on fd %i", fd);
e0e72660 JG	500	goto end;
	501	}
	502
	503	id.device = statbuf.st_dev;
	504	id.inode = statbuf.st_ino;
	505
	506	rcu_read_lock();
5c1f54d1 JG	507	cds_lfht_lookup(registry->inodes, lttng_inode_id_hash(&id),
5c1f54d1 JG	508	lttng_inode_match, &id, &iter);
e0e72660 JG	509	node = cds_lfht_iter_get_node(&iter);
e0e72660 JG	510	if (node) {
5c1f54d1 JG	511	inode = caa_container_of(
5c1f54d1 JG	512	node, struct lttng_inode, registry_node);
e0e72660 JG	513	lttng_inode_get(inode);
	514	goto end_unlock;
	515	}
	516
f7c3ffd7 JG	517	inode = lttng_inode_create(&id, registry->inodes, unlinked_file_pool,
f7c3ffd7 JG	518	handle, path);
e0e72660	519	node = cds_lfht_add_unique(registry->inodes,
5c1f54d1 JG	520	lttng_inode_id_hash(&inode->id), lttng_inode_match,
5c1f54d1 JG	521	&inode->id, &inode->registry_node);
e0e72660 JG	522	assert(node == &inode->registry_node);
	523	end_unlock:
	524	rcu_read_unlock();
	525	end:
	526	return inode;
	527	}