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

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

#include <common/defaults.hpp>
#include <common/error.hpp>
#include <common/hashtable/utils.hpp>
#include <common/macros.hpp>
#include <common/optional.hpp>
#include <common/string-utils/format.hpp>
#include <common/utils.hpp>
#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.hpp"

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,
		.initialized = false,
		.value = 0,
};

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 = (inode_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);
		LTTNG_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);
		if (!pool->unlink_directory_handle) {
			ERR("Failed to create directory handle to unlinked file pool at %s",
					pool->unlink_directory_path);
			ret = -1;
			goto end;
		}
	}

	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);
	LTTNG_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;

		LTTNG_ASSERT(inode->location.directory_handle);
		LTTNG_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<lttng_unlinked_file_pool>();

	if (!pool) {
		goto error;
	}

	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;
	}

	LTTNG_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);

		LTTNG_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);
	LTTNG_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);
	LTTNG_ASSERT(reference_acquired);

	inode = zmalloc<lttng_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<lttng_inode_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);

		LTTNG_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);
	if (!inode) {
		goto end_unlock;
	}

	node = cds_lfht_add_unique(registry->inodes,
			lttng_inode_id_hash(&inode->id), lttng_inode_match,
			&inode->id, &inode->registry_node);
	LTTNG_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
c9e313bc SM	8	#include <common/defaults.hpp>
	9	#include <common/error.hpp>
	10	#include <common/hashtable/utils.hpp>
	11	#include <common/macros.hpp>
	12	#include <common/optional.hpp>
	13	#include <common/string-utils/format.hpp>
	14	#include <common/utils.hpp>
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	23
c9e313bc	24	#include "inode.hpp"
e0e72660 JG	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,
1c9a0b0e MJ	69	.initialized = false,
1c9a0b0e MJ	70	.value = 0,
e0e72660 JG	71	};
e0e72660 JG	72
f7c3ffd7	73	static unsigned long lttng_inode_id_hash(const struct inode_id *id)
e0e72660 JG	74	{
	75	uint64_t device = id->device, inode_no = id->inode;
	76
5c1f54d1 JG	77	return hash_key_u64(&device, seed.value) ^
5c1f54d1 JG	78	hash_key_u64(&inode_no, seed.value);
e0e72660 JG	79	}
e0e72660 JG	80
5c1f54d1	81	static int lttng_inode_match(struct cds_lfht_node node, const void key)
e0e72660	82	{
e032c6fd	83	const struct inode_id id = (inode_id ) key;
f7c3ffd7	84	const struct lttng_inode *inode = caa_container_of(
5c1f54d1	85	node, struct lttng_inode, registry_node);
e0e72660 JG	86
	87	return inode->id.device == id->device && inode->id.inode == id->inode;
	88	}
	89
f7c3ffd7	90	static void lttng_inode_free(struct rcu_head *head)
e0e72660	91	{
5c1f54d1 JG	92	struct lttng_inode *inode =
5c1f54d1 JG	93	caa_container_of(head, struct lttng_inode, rcu_head);
e0e72660	94
e0e72660 JG	95	free(inode);
	96	}
	97
f7c3ffd7 JG	98	static int lttng_unlinked_file_pool_add_inode(
	99	struct lttng_unlinked_file_pool *pool,
	100	struct lttng_inode *inode)
	101	{
	102	int ret;
	103	const unsigned int unlinked_id = pool->next_id++;
	104	char *inode_unlinked_name;
	105	bool reference_acquired;
	106
	107	DBG("Adding inode of %s to unlinked file pool as id %u",
	108	inode->location.path, unlinked_id);
	109	ret = asprintf(&inode_unlinked_name, "%u", unlinked_id);
	110	if (ret < 0) {
	111	ERR("Failed to format unlinked inode name");
	112	ret = -1;
	113	goto end;
	114	}
	115
	116	if (pool->file_count == 0) {
	117	DBG("Creating unlinked files directory at %s",
	118	pool->unlink_directory_path);
a0377dfe	119	LTTNG_ASSERT(!pool->unlink_directory_handle);
f7c3ffd7 JG	120	ret = utils_mkdir(pool->unlink_directory_path,
	121	S_IRWXU \| S_IRWXG, -1, -1);
	122	if (ret) {
	123	if (errno == EEXIST) {
	124	/*
	125	* Unexpected (previous crash?), but not an
	126	* error.
	127	*/
	128	DBG("Unlinked file directory \"%s\" already exists",
	129	pool->unlink_directory_path);
	130	} else {
	131	PERROR("Failed to create unlinked files directory at %s",
	132	pool->unlink_directory_path);
	133	goto end;
	134	}
	135	}
	136	pool->unlink_directory_handle = lttng_directory_handle_create(
	137	pool->unlink_directory_path);
d05a3d93 JG	138	if (!pool->unlink_directory_handle) {
	139	ERR("Failed to create directory handle to unlinked file pool at %s",
	140	pool->unlink_directory_path);
	141	ret = -1;
	142	goto end;
	143	}
f7c3ffd7 JG	144	}
	145
	146	ret = lttng_directory_handle_rename(inode->location.directory_handle,
	147	inode->location.path, pool->unlink_directory_handle,
	148	inode_unlinked_name);
	149	if (ret) {
	150	goto end;
	151	}
	152
	153	lttng_directory_handle_put(inode->location.directory_handle);
	154	inode->location.directory_handle = NULL;
	155	reference_acquired = lttng_directory_handle_get(
	156	pool->unlink_directory_handle);
a0377dfe	157	LTTNG_ASSERT(reference_acquired);
f7c3ffd7 JG	158	inode->location.directory_handle = pool->unlink_directory_handle;
	159
	160	free(inode->location.path);
	161	inode->location.path = inode_unlinked_name;
	162	inode_unlinked_name = NULL;
	163	LTTNG_OPTIONAL_SET(&inode->unlinked_id, unlinked_id);
	164	pool->file_count++;
	165	end:
	166	free(inode_unlinked_name);
	167	return ret;
	168	}
	169
	170	static int lttng_unlinked_file_pool_remove_inode(
	171	struct lttng_unlinked_file_pool *pool,
	172	struct lttng_inode *inode)
	173	{
	174	int ret;
	175
	176	DBG("Removing inode with unlinked id %u from unlinked file pool",
	177	LTTNG_OPTIONAL_GET(inode->unlinked_id));
	178
	179	ret = lttng_directory_handle_unlink_file(
	180	inode->location.directory_handle, inode->location.path);
	181	if (ret) {
	182	PERROR("Failed to unlink file %s from unlinked file directory",
	183	inode->location.path);
	184	goto end;
	185	}
	186	free(inode->location.path);
	187	inode->location.path = NULL;
	188	lttng_directory_handle_put(inode->location.directory_handle);
	189	inode->location.directory_handle = NULL;
	190
	191	pool->file_count--;
	192	if (pool->file_count == 0) {
	193	ret = utils_recursive_rmdir(pool->unlink_directory_path);
	194	if (ret) {
	195	/*
	196	* There is nothing the caller can do, don't report an
	197	* error except through logging.
	198	*/
	199	PERROR("Failed to remove unlinked files directory at %s",
	200	pool->unlink_directory_path);
	201	}
	202	lttng_directory_handle_put(pool->unlink_directory_handle);
	203	pool->unlink_directory_handle = NULL;
	204	}
	205	end:
	206	return ret;
	207	}
	208
5c1f54d1	209	static void lttng_inode_destroy(struct lttng_inode *inode)
e0e72660 JG	210	{
	211	if (!inode) {
	212	return;
	213	}
f7c3ffd7 JG	214
	215	rcu_read_lock();
	216	cds_lfht_del(inode->registry_ht, &inode->registry_node);
	217	rcu_read_unlock();
	218
e0e72660	219	if (inode->unlink_pending) {
f7c3ffd7	220	int ret;
e0e72660	221
a0377dfe FD	222	LTTNG_ASSERT(inode->location.directory_handle);
a0377dfe FD	223	LTTNG_ASSERT(inode->location.path);
f7c3ffd7 JG	224	DBG("Removing %s from unlinked file pool",
	225	inode->location.path);
	226	ret = lttng_unlinked_file_pool_remove_inode(inode->unlinked_file_pool, inode);
e0e72660	227	if (ret) {
f7c3ffd7	228	PERROR("Failed to unlink %s", inode->location.path);
e0e72660 JG	229	}
e0e72660 JG	230	}
f7c3ffd7 JG	231
	232	lttng_directory_handle_put(
	233	inode->location.directory_handle);
	234	inode->location.directory_handle = NULL;
	235	free(inode->location.path);
	236	inode->location.path = NULL;
	237	call_rcu(&inode->rcu_head, lttng_inode_free);
e0e72660 JG	238	}
e0e72660 JG	239
5c1f54d1	240	static void lttng_inode_release(struct urcu_ref *ref)
e0e72660	241	{
5c1f54d1	242	lttng_inode_destroy(caa_container_of(ref, struct lttng_inode, ref));
e0e72660 JG	243	}
e0e72660 JG	244
5c1f54d1	245	static void lttng_inode_get(struct lttng_inode *inode)
e0e72660 JG	246	{
	247	urcu_ref_get(&inode->ref);
	248	}
	249
ca806b0b	250	struct lttng_unlinked_file_pool *lttng_unlinked_file_pool_create(
f7c3ffd7 JG	251	const char *path)
f7c3ffd7 JG	252	{
64803277	253	struct lttng_unlinked_file_pool *pool = zmalloc<lttng_unlinked_file_pool>();
f7c3ffd7	254
9604bd17 JG	255	if (!pool) {
	256	goto error;
	257	}
	258
f7c3ffd7 JG	259	if (!path \|\| *path != '/') {
	260	ERR("Unlinked file pool must be created with an absolute path, path = \"%s\"",
	261	path ? path : "NULL");
	262	goto error;
	263	}
	264
	265	pool->unlink_directory_path = strdup(path);
	266	if (!pool->unlink_directory_path) {
	267	PERROR("Failed to allocation unlinked file pool path");
	268	goto error;
	269	}
	270	DBG("Unlinked file pool created at: %s", path);
	271	return pool;
	272	error:
	273	lttng_unlinked_file_pool_destroy(pool);
	274	return NULL;
	275	}
	276
ca806b0b	277	void lttng_unlinked_file_pool_destroy(
f7c3ffd7 JG	278	struct lttng_unlinked_file_pool *pool)
	279	{
	280	if (!pool) {
	281	return;
	282	}
	283
a0377dfe	284	LTTNG_ASSERT(pool->file_count == 0);
f7c3ffd7 JG	285	lttng_directory_handle_put(pool->unlink_directory_handle);
	286	free(pool->unlink_directory_path);
	287	free(pool);
	288	}
	289
ca806b0b	290	void lttng_inode_put(struct lttng_inode *inode)
e0e72660 JG	291	{
	292	urcu_ref_put(&inode->ref, lttng_inode_release);
	293	}
	294
ca806b0b	295	struct lttng_directory_handle *
938bd422	296	lttng_inode_get_location_directory_handle(
dd95933f JG	297	struct lttng_inode *inode)
	298	{
	299	if (inode->location.directory_handle) {
	300	const bool reference_acquired = lttng_directory_handle_get(
	301	inode->location.directory_handle);
	302
a0377dfe	303	LTTNG_ASSERT(reference_acquired);
dd95933f JG	304	}
	305	return inode->location.directory_handle;
	306	}
	307
ca806b0b	308	void lttng_inode_borrow_location(struct lttng_inode *inode,
f7c3ffd7 JG	309	const struct lttng_directory_handle **out_directory_handle,
f7c3ffd7 JG	310	const char **out_path)
e0e72660	311	{
f7c3ffd7 JG	312	if (out_directory_handle) {
	313	*out_directory_handle = inode->location.directory_handle;
	314	}
	315	if (out_path) {
	316	*out_path = inode->location.path;
	317	}
e0e72660 JG	318	}
e0e72660 JG	319
ca806b0b	320	int lttng_inode_rename(
f7c3ffd7 JG	321	struct lttng_inode *inode,
	322	struct lttng_directory_handle *old_directory_handle,
	323	const char *old_path,
	324	struct lttng_directory_handle *new_directory_handle,
	325	const char *new_path,
	326	bool overwrite)
e0e72660 JG	327	{
e0e72660 JG	328	int ret = 0;
f7c3ffd7 JG	329	char *new_path_copy = strdup(new_path);
	330	bool reference_acquired;
	331
	332	DBG("Performing rename of inode from %s to %s with %s directory handles",
	333	old_path, new_path,
	334	lttng_directory_handle_equals(old_directory_handle,
	335	new_directory_handle) ?
	336	"identical" :
	337	"different");
	338
	339	if (!new_path_copy) {
	340	ret = -ENOMEM;
	341	goto end;
	342	}
e0e72660 JG	343
e0e72660 JG	344	if (inode->unlink_pending) {
f7c3ffd7 JG	345	WARN("An attempt to rename an unlinked file from %s to %s has been performed",
f7c3ffd7 JG	346	old_path, new_path);
e0e72660 JG	347	ret = -ENOENT;
	348	goto end;
	349	}
	350
	351	if (!overwrite) {
f7c3ffd7	352	/* Verify that file doesn't exist. */
e0e72660 JG	353	struct stat statbuf;
e0e72660 JG	354
f7c3ffd7 JG	355	ret = lttng_directory_handle_stat(
f7c3ffd7 JG	356	new_directory_handle, new_path, &statbuf);
e0e72660	357	if (ret == 0) {
f7c3ffd7 JG	358	ERR("Refusing to rename %s as the destination already exists",
f7c3ffd7 JG	359	old_path);
e0e72660 JG	360	ret = -EEXIST;
	361	goto end;
	362	} else if (ret < 0 && errno != ENOENT) {
	363	PERROR("Failed to stat() %s", new_path);
	364	ret = -errno;
	365	goto end;
	366	}
	367	}
	368
f7c3ffd7 JG	369	ret = lttng_directory_handle_rename(old_directory_handle, old_path,
f7c3ffd7 JG	370	new_directory_handle, new_path);
e0e72660	371	if (ret) {
f7c3ffd7	372	PERROR("Failed to rename file %s to %s", old_path, new_path);
e0e72660 JG	373	ret = -errno;
	374	goto end;
	375	}
	376
f7c3ffd7	377	reference_acquired = lttng_directory_handle_get(new_directory_handle);
a0377dfe	378	LTTNG_ASSERT(reference_acquired);
f7c3ffd7 JG	379	lttng_directory_handle_put(inode->location.directory_handle);
	380	free(inode->location.path);
	381	inode->location.directory_handle = new_directory_handle;
	382	/* Ownership transferred. */
	383	inode->location.path = new_path_copy;
e0e72660 JG	384	new_path_copy = NULL;
	385	end:
	386	free(new_path_copy);
	387	return ret;
	388	}
	389
ca806b0b	390	int lttng_inode_unlink(struct lttng_inode *inode)
e0e72660 JG	391	{
e0e72660 JG	392	int ret = 0;
f7c3ffd7 JG	393
f7c3ffd7 JG	394	DBG("Attempting unlink of inode %s", inode->location.path);
e0e72660 JG	395
	396	if (inode->unlink_pending) {
	397	WARN("An attempt to re-unlink %s has been performed, ignoring.",
f7c3ffd7	398	inode->location.path);
e0e72660 JG	399	ret = -ENOENT;
	400	goto end;
	401	}
	402
f7c3ffd7 JG	403	/*
	404	* Move to the temporary "deleted" directory until all
	405	* references are released.
	406	*/
	407	ret = lttng_unlinked_file_pool_add_inode(
	408	inode->unlinked_file_pool, inode);
	409	if (ret) {
	410	PERROR("Failed to add inode \"%s\" to the unlinked file pool",
	411	inode->location.path);
e0e72660 JG	412	goto end;
e0e72660 JG	413	}
f7c3ffd7	414	inode->unlink_pending = true;
e0e72660 JG	415	end:
	416	return ret;
	417	}
	418
5c1f54d1	419	static struct lttng_inode lttng_inode_create(const struct inode_id id,
f7c3ffd7 JG	420	struct cds_lfht *ht,
	421	struct lttng_unlinked_file_pool *unlinked_file_pool,
	422	struct lttng_directory_handle *directory_handle,
	423	const char *path)
e0e72660	424	{
f7c3ffd7 JG	425	struct lttng_inode *inode = NULL;
	426	char *path_copy;
	427	bool reference_acquired;
	428
	429	path_copy = strdup(path);
	430	if (!path_copy) {
	431	goto end;
	432	}
e0e72660	433
f7c3ffd7	434	reference_acquired = lttng_directory_handle_get(directory_handle);
a0377dfe	435	LTTNG_ASSERT(reference_acquired);
f7c3ffd7	436
64803277	437	inode = zmalloc<lttng_inode>();
e0e72660 JG	438	if (!inode) {
	439	goto end;
	440	}
	441
	442	urcu_ref_init(&inode->ref);
	443	cds_lfht_node_init(&inode->registry_node);
	444	inode->id = *id;
e0e72660	445	inode->registry_ht = ht;
f7c3ffd7 JG	446	inode->unlinked_file_pool = unlinked_file_pool;
	447	/* Ownership of path copy is transferred to inode. */
	448	inode->location.path = path_copy;
	449	path_copy = NULL;
	450	inode->location.directory_handle = directory_handle;
e0e72660	451	end:
f7c3ffd7	452	free(path_copy);
e0e72660	453	return inode;
e0e72660 JG	454	}
e0e72660 JG	455
ca806b0b	456	struct lttng_inode_registry *lttng_inode_registry_create(void)
e0e72660	457	{
64803277	458	struct lttng_inode_registry *registry = zmalloc<lttng_inode_registry>();
e0e72660 JG	459
	460	if (!registry) {
	461	goto end;
	462	}
	463
	464	pthread_mutex_lock(&seed.lock);
	465	if (!seed.initialized) {
	466	seed.value = (unsigned long) time(NULL);
	467	seed.initialized = true;
	468	}
	469	pthread_mutex_unlock(&seed.lock);
	470
	471	registry->inodes = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
	472	CDS_LFHT_AUTO_RESIZE \| CDS_LFHT_ACCOUNTING, NULL);
	473	if (!registry->inodes) {
	474	goto error;
	475	}
	476	end:
	477	return registry;
	478	error:
	479	lttng_inode_registry_destroy(registry);
	480	return NULL;
	481	}
	482
ca806b0b	483	void lttng_inode_registry_destroy(
938bd422	484	struct lttng_inode_registry *registry)
e0e72660 JG	485	{
	486	if (!registry) {
	487	return;
	488	}
	489	if (registry->inodes) {
	490	int ret = cds_lfht_destroy(registry->inodes, NULL);
	491
a0377dfe	492	LTTNG_ASSERT(!ret);
e0e72660 JG	493	}
	494	free(registry);
	495	}
	496
ca806b0b	497	struct lttng_inode *lttng_inode_registry_get_inode(
f7c3ffd7 JG	498	struct lttng_inode_registry *registry,
	499	struct lttng_directory_handle *handle,
	500	const char *path,
	501	int fd,
	502	struct lttng_unlinked_file_pool *unlinked_file_pool)
e0e72660 JG	503	{
	504	int ret;
	505	struct stat statbuf;
	506	struct inode_id id;
	507	struct cds_lfht_iter iter;
	508	struct cds_lfht_node *node;
	509	struct lttng_inode *inode = NULL;
	510
	511	ret = fstat(fd, &statbuf);
	512	if (ret < 0) {
f7c3ffd7	513	PERROR("stat() failed on fd %i", fd);
e0e72660 JG	514	goto end;
	515	}
	516
	517	id.device = statbuf.st_dev;
	518	id.inode = statbuf.st_ino;
	519
	520	rcu_read_lock();
5c1f54d1 JG	521	cds_lfht_lookup(registry->inodes, lttng_inode_id_hash(&id),
5c1f54d1 JG	522	lttng_inode_match, &id, &iter);
e0e72660 JG	523	node = cds_lfht_iter_get_node(&iter);
e0e72660 JG	524	if (node) {
5c1f54d1 JG	525	inode = caa_container_of(
5c1f54d1 JG	526	node, struct lttng_inode, registry_node);
e0e72660 JG	527	lttng_inode_get(inode);
	528	goto end_unlock;
	529	}
	530
f7c3ffd7 JG	531	inode = lttng_inode_create(&id, registry->inodes, unlinked_file_pool,
f7c3ffd7 JG	532	handle, path);
640b9481 JR	533	if (!inode) {
	534	goto end_unlock;
	535	}
	536
e0e72660	537	node = cds_lfht_add_unique(registry->inodes,
5c1f54d1 JG	538	lttng_inode_id_hash(&inode->id), lttng_inode_match,
5c1f54d1 JG	539	&inode->id, &inode->registry_node);
a0377dfe	540	LTTNG_ASSERT(node == &inode->registry_node);
e0e72660 JG	541	end_unlock:
	542	rcu_read_unlock();
	543	end:
	544	return inode;
	545	}