Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2201 insertions, 0 deletions

diff --git a/src/include/cephfs/libcephfs.h b/src/include/cephfs/libcephfs.h
new file mode 100644
index 000000000..dc62698fa
--- /dev/null
+++ b/src/include/cephfs/libcephfs.h
@@ -0,0 +1,2201 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2009-2011 New Dream Network
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#ifndef CEPH_LIB_H
+#define CEPH_LIB_H
+
+#if defined(__linux__)
+#include <features.h>
+#endif
+#include <utime.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/statvfs.h>
+#include <sys/socket.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <dirent.h>
+
+#include "ceph_ll_client.h"
+
+#ifdef __cplusplus
+namespace ceph::common {
+  class CephContext;
+}
+using CephContext = ceph::common::CephContext;
+extern "C" {
+#endif
+
+#define LIBCEPHFS_VER_MAJOR 10
+#define LIBCEPHFS_VER_MINOR 0
+#define LIBCEPHFS_VER_EXTRA 3
+
+#define LIBCEPHFS_VERSION(maj, min, extra) ((maj << 16) + (min << 8) + extra)
+#define LIBCEPHFS_VERSION_CODE LIBCEPHFS_VERSION(LIBCEPHFS_VER_MAJOR, LIBCEPHFS_VER_MINOR, LIBCEPHFS_VER_EXTRA)
+
+#if __GNUC__ >= 4
+  #define LIBCEPHFS_DEPRECATED   __attribute__((deprecated))
+  #pragma GCC diagnostic push
+  #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#else
+  #define LIBCEPHFS_DEPRECATED
+#endif
+
+/*
+ * If using glibc check that file offset is 64-bit.
+ */
+#if defined(__GLIBC__) && !defined(__USE_FILE_OFFSET64)
+# error libceph: glibc must define __USE_FILE_OFFSET64 or readdir results will be corrupted
+#endif
+
+/*
+ * XXXX redeclarations from ceph_fs.h, rados.h, etc.  We need more of this
+ * in the interface, but shouldn't be re-typing it (and using different
+ * C data types).
+ */
+#ifndef __cplusplus
+
+#define CEPH_INO_ROOT  1
+#define CEPH_NOSNAP  ((uint64_t)(-2))
+
+struct ceph_file_layout {
+	/* file -> object mapping */
+	uint32_t fl_stripe_unit;     /* stripe unit, in bytes.  must be multiple
+				      of page size. */
+	uint32_t fl_stripe_count;    /* over this many objects */
+	uint32_t fl_object_size;     /* until objects are this big, then move to
+				      new objects */
+	uint32_t fl_cas_hash;        /* 0 = none; 1 = sha256 */
+
+	/* pg -> disk layout */
+	uint32_t fl_object_stripe_unit;  /* for per-object parity, if any */
+
+	/* object -> pg layout */
+	uint32_t fl_pg_preferred; /* preferred primary for pg (-1 for none) */
+	uint32_t fl_pg_pool;      /* namespace, crush rule, rep level */
+} __attribute__ ((packed));
+
+struct CephContext;
+#endif /* ! __cplusplus */
+
+struct UserPerm;
+typedef struct UserPerm UserPerm;
+
+struct Inode;
+typedef struct Inode Inode;
+
+struct ceph_mount_info;
+struct ceph_dir_result;
+
+// user supplied key,value pair to be associated with a snapshot.
+// callers can supply an array of this struct via ceph_mksnap().
+struct snap_metadata {
+  const char *key;
+  const char *value;
+};
+
+struct snap_info {
+  uint64_t id;
+  size_t nr_snap_metadata;
+  struct snap_metadata *snap_metadata;
+};
+
+struct ceph_snapdiff_entry_t {
+  struct dirent dir_entry;
+  uint64_t snapid; //should be snapid_t but prefer not to exposure it
+};
+
+/* setattr mask bits (up to an int in size) */
+#ifndef CEPH_SETATTR_MODE
+#define CEPH_SETATTR_MODE		(1 << 0)
+#define CEPH_SETATTR_UID		(1 << 1)
+#define CEPH_SETATTR_GID		(1 << 2)
+#define CEPH_SETATTR_MTIME		(1 << 3)
+#define CEPH_SETATTR_ATIME		(1 << 4)
+#define CEPH_SETATTR_SIZE		(1 << 5)
+#define CEPH_SETATTR_CTIME		(1 << 6)
+#define CEPH_SETATTR_MTIME_NOW		(1 << 7)
+#define CEPH_SETATTR_ATIME_NOW		(1 << 8)
+#define CEPH_SETATTR_BTIME		(1 << 9)
+#define CEPH_SETATTR_KILL_SGUID		(1 << 10)
+#define CEPH_SETATTR_FSCRYPT_AUTH	(1 << 11)
+#define CEPH_SETATTR_FSCRYPT_FILE	(1 << 12)
+#define CEPH_SETATTR_KILL_SUID		(1 << 13)
+#define CEPH_SETATTR_KILL_SGID		(1 << 14)
+#endif
+
+/* define error codes for the mount function*/
+# define CEPHFS_ERROR_MON_MAP_BUILD 1000
+# define CEPHFS_ERROR_NEW_CLIENT 1002
+# define CEPHFS_ERROR_MESSENGER_START 1003
+
+/**
+ * Create a UserPerm credential object.
+ *
+ * Some calls (most notably, the ceph_ll_* ones), take a credential object
+ * that represents the credentials that the calling program is using. This
+ * function creates a new credential object for this purpose. Returns a
+ * pointer to the object, or NULL if it can't be allocated.
+ *
+ * Note that the gidlist array is used directly and is not copied. It must
+ * remain valid over the lifetime of the created UserPerm object.
+ *
+ * @param uid uid to be used
+ * @param gid gid to be used
+ * @param ngids number of gids in supplemental grouplist
+ * @param gidlist array of gid_t's in the list of groups
+ */
+UserPerm *ceph_userperm_new(uid_t uid, gid_t gid, int ngids, gid_t *gidlist);
+
+/**
+ * Destroy a UserPerm credential object.
+ *
+ * @param perm pointer to object to be destroyed
+ *
+ * Currently this just frees the object. Note that the gidlist array is not
+ * freed. The caller must do so if it's necessary.
+ */
+void ceph_userperm_destroy(UserPerm *perm);
+
+/**
+ * Get a pointer to the default UserPerm object for the mount.
+ *
+ * @param cmount the mount info handle
+ *
+ * Every cmount has a default set of credentials. This returns a pointer to
+ * that object.
+ *
+ * Unlike with ceph_userperm_new, this object should not be freed.
+ */
+struct UserPerm *ceph_mount_perms(struct ceph_mount_info *cmount);
+
+/**
+ * Set cmount's default permissions
+ *
+ * @param cmount the mount info handle
+ * @param perm permissions to set to default for mount
+ *
+ * Every cmount has a default set of credentials. This does a deep copy of
+ * the given permissions to the ones in the cmount. Must be done after
+ * ceph_init but before ceph_mount.
+ *
+ * Returns 0 on success, and -EISCONN if the cmount is already mounted.
+ */
+int ceph_mount_perms_set(struct ceph_mount_info *cmount, UserPerm *perm);
+
+/**
+ * @defgroup libcephfs_h_init Setup and Teardown
+ * These are the first and last functions that should be called
+ * when using libcephfs.
+ *
+ * @{
+ */
+
+/**
+ * Get the version of libcephfs.
+ *
+ * The version number is major.minor.patch.
+ *
+ * @param major where to store the major version number
+ * @param minor where to store the minor version number
+ * @param patch where to store the extra version number
+ */
+const char *ceph_version(int *major, int *minor, int *patch);
+
+/**
+ * Create a mount handle for interacting with Ceph.  All libcephfs
+ * functions operate on a mount info handle.
+ *
+ * @param cmount the mount info handle to initialize
+ * @param id the id of the client.  This can be a unique id that identifies
+ *           this client, and will get appended onto "client.".  Callers can
+ *           pass in NULL, and the id will be the process id of the client.
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_create(struct ceph_mount_info **cmount, const char * const id);
+
+/**
+ * Create a mount handle from a CephContext, which holds the configuration
+ * for the ceph cluster.  A CephContext can be acquired from an existing ceph_mount_info
+ * handle, using the @ref ceph_get_mount_context call.  Note that using the same CephContext
+ * for two different mount handles results in the same client entity id being used.
+ *
+ * @param cmount the mount info handle to initialize
+ * @param conf reuse this pre-existing CephContext config
+ * @returns 0 on success, negative error code on failure
+ */
+#ifdef __cplusplus
+int ceph_create_with_context(struct ceph_mount_info **cmount, CephContext *conf);
+#else
+int ceph_create_with_context(struct ceph_mount_info **cmount, struct CephContext *conf);
+#endif
+
+#ifndef VOIDPTR_RADOS_T
+#define VOIDPTR_RADOS_T
+typedef void *rados_t;
+#endif // VOIDPTR_RADOS_T
+
+/**
+ * Create a mount handle from a rados_t, for using libcephfs in the
+ * same process as librados.
+ *
+ * @param cmount the mount info handle to initialize
+ * @param cluster reference to already-initialized librados handle
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_create_from_rados(struct ceph_mount_info **cmount, rados_t cluster);
+
+/**
+ * Initialize the filesystem client (but do not mount the filesystem yet)
+ *
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_init(struct ceph_mount_info *cmount);
+
+/**
+ * Optionally set which filesystem to mount, before calling mount.
+ *
+ * An error will be returned if this libcephfs instance is already
+ * mounted. This function is an alternative to setting the global
+ * client_fs setting.  Using this function enables multiple libcephfs
+ * instances in the same process to mount different filesystems.
+ *
+ * The filesystem name is *not* validated in this function.  That happens
+ * during mount(), where an ENOENT error will result if a non-existent
+ * filesystem was specified here.
+ *
+ * @param cmount the mount info handle
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_select_filesystem(struct ceph_mount_info *cmount, const char *fs_name);
+
+
+/**
+ * Perform a mount using the path for the root of the mount.
+ *
+ * It is optional to call ceph_init before this.  If ceph_init has
+ * not already been called, it will be called in the course of this operation.
+ *
+ * @param cmount the mount info handle
+ * @param root the path for the root of the mount.  This can be an existing
+ *	       directory within the ceph cluster, but most likely it will
+ * 	       be "/".  Passing in NULL is equivalent to "/".
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_mount(struct ceph_mount_info *cmount, const char *root);
+
+/**
+ * Return cluster ID for a mounted ceph filesystem
+ *
+ * Every ceph filesystem has a filesystem ID associated with it. This
+ * function returns that value. If the ceph_mount_info does not refer to a
+ * mounted filesystem, this returns a negative error code.
+ */
+int64_t ceph_get_fs_cid(struct ceph_mount_info *cmount);
+
+/**
+ * Execute a management command remotely on an MDS.
+ *
+ * Must have called ceph_init or ceph_mount before calling this.
+ *
+ * @param mds_spec string representing rank, MDS name, GID or '*'
+ * @param cmd array of null-terminated strings
+ * @param cmdlen length of cmd array
+ * @param inbuf non-null-terminated input data to command
+ * @param inbuflen length in octets of inbuf
+ * @param outbuf populated with pointer to buffer (command output data)
+ * @param outbuflen length of allocated outbuf
+ * @param outs populated with pointer to buffer (command error strings)
+ * @param outslen length of allocated outs
+ *
+ * @return 0 on success, negative error code on failure
+ *
+ */
+int ceph_mds_command(struct ceph_mount_info *cmount,
+    const char *mds_spec,
+    const char **cmd,
+    size_t cmdlen,
+    const char *inbuf, size_t inbuflen,
+    char **outbuf, size_t *outbuflen,
+    char **outs, size_t *outslen);
+
+/**
+ * Free a buffer, such as those used for output arrays from ceph_mds_command
+ */
+void ceph_buffer_free(char *buf);
+
+/**
+ * Unmount a mount handle.
+ *
+ * @param cmount the mount handle
+ * @return 0 on success, negative error code on failure
+ */
+int ceph_unmount(struct ceph_mount_info *cmount);
+
+/**
+ * Abort mds connections
+ *
+ * @param cmount the mount handle
+ * @return 0 on success, negative error code on failure
+ */
+int ceph_abort_conn(struct ceph_mount_info *cmount);
+
+/**
+ * Destroy the mount handle.
+ *
+ * The handle should not be mounted. This should be called on completion of
+ * all libcephfs functions.
+ *
+ * @param cmount the mount handle
+ * @return 0 on success, negative error code on failure.
+ */
+int ceph_release(struct ceph_mount_info *cmount);
+
+/**
+ * Deprecated. Unmount and destroy the ceph mount handle. This should be
+ * called on completion of all libcephfs functions.
+ *
+ * Equivalent to ceph_unmount() + ceph_release() without error handling.
+ *
+ * @param cmount the mount handle to shutdown
+ */
+void ceph_shutdown(struct ceph_mount_info *cmount);
+
+/**
+ * Return associated client addresses
+ *
+ * @param cmount the mount handle
+ * @param addrs the output addresses
+ * @returns 0 on success, a negative error code on failure
+ * @note the returned addrs should be free by the caller
+ */
+int ceph_getaddrs(struct ceph_mount_info *cmount, char** addrs);
+
+/**
+ * Get a global id for current instance
+ *
+ * The handle should not be mounted. This should be called on completion of
+ * all libcephfs functions.
+ *
+ * @param cmount the mount handle
+ * @returns instance global id
+ */
+uint64_t ceph_get_instance_id(struct ceph_mount_info *cmount);
+
+/**
+ * Extract the CephContext from the mount point handle.
+ *
+ * @param cmount the ceph mount handle to get the context from.
+ * @returns the CephContext associated with the mount handle.
+ */
+#ifdef __cplusplus
+CephContext *ceph_get_mount_context(struct ceph_mount_info *cmount);
+#else
+struct CephContext *ceph_get_mount_context(struct ceph_mount_info *cmount);
+#endif
+/*
+ * Check mount status.
+ *
+ * Return non-zero value if mounted. Otherwise, zero.
+ */
+int ceph_is_mounted(struct ceph_mount_info *cmount);
+
+/** @} init */
+
+/**
+ * @defgroup libcephfs_h_config Config
+ * Functions for manipulating the Ceph configuration at runtime.
+ *
+ * @{
+ */
+
+/**
+ * Load the ceph configuration from the specified config file.
+ *
+ * @param cmount the mount handle to load the configuration into.
+ * @param path_list the configuration file path
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_conf_read_file(struct ceph_mount_info *cmount, const char *path_list);
+
+/**
+ * Parse the command line arguments and load the configuration parameters.
+ *
+ * @param cmount the mount handle to load the configuration parameters into.
+ * @param argc count of the arguments in argv
+ * @param argv the argument list
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_conf_parse_argv(struct ceph_mount_info *cmount, int argc, const char **argv);
+
+/**
+ * Configure the cluster handle based on an environment variable
+ *
+ * The contents of the environment variable are parsed as if they were
+ * Ceph command line options. If var is NULL, the CEPH_ARGS
+ * environment variable is used.
+ *
+ * @pre ceph_mount() has not been called on the handle
+ *
+ * @note BUG: this is not threadsafe - it uses a static buffer
+ *
+ * @param cmount handle to configure
+ * @param var name of the environment variable to read
+ * @returns 0 on success, negative error code on failure
+ */
+int ceph_conf_parse_env(struct ceph_mount_info *cmount, const char *var);
+
+/** Sets a configuration value from a string.
+ *
+ * @param cmount the mount handle to set the configuration value on
+ * @param option the configuration option to set
+ * @param value the value of the configuration option to set
+ * 
+ * @returns 0 on success, negative error code otherwise.
+ */
+int ceph_conf_set(struct ceph_mount_info *cmount, const char *option, const char *value);
+
+/** Set mount timeout.
+ *
+ * @param cmount mount handle to set the configuration value on
+ * @param timeout mount timeout interval
+ *
+ * @returns 0 on success, negative error code otherwise.
+ */
+int ceph_set_mount_timeout(struct ceph_mount_info *cmount, uint32_t timeout);
+
+/**
+ * Gets the configuration value as a string.
+ *
+ * @param cmount the mount handle to set the configuration value on
+ * @param option the config option to get
+ * @param buf the buffer to fill with the value
+ * @param len the length of the buffer.
+ * @returns the size of the buffer filled in with the value, or negative error code on failure
+ */
+int ceph_conf_get(struct ceph_mount_info *cmount, const char *option, char *buf, size_t len);
+
+/** @} config */
+
+/**
+ * @defgroup libcephfs_h_fsops File System Operations.
+ * Functions for getting/setting file system wide information specific to a particular
+ * mount handle.
+ *
+ * @{
+ */
+
+/**
+ * Perform a statfs on the ceph file system.  This call fills in file system wide statistics
+ * into the passed in buffer.
+ *
+ * @param cmount the ceph mount handle to use for performing the statfs.
+ * @param path can be any path within the mounted filesystem
+ * @param stbuf the file system statistics filled in by this function.
+ * @return 0 on success, negative error code otherwise.
+ */
+int ceph_statfs(struct ceph_mount_info *cmount, const char *path, struct statvfs *stbuf);
+
+/**
+ * Synchronize all filesystem data to persistent media.
+ *
+ * @param cmount the ceph mount handle to use for performing the sync_fs.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_sync_fs(struct ceph_mount_info *cmount);
+
+/**
+ * Get the current working directory.
+ *
+ * @param cmount the ceph mount to get the current working directory for.
+ * @returns the path to the current working directory
+ */
+const char* ceph_getcwd(struct ceph_mount_info *cmount);
+
+/**
+ * Change the current working directory.
+ *
+ * @param cmount the ceph mount to change the current working directory for.
+ * @param path the path to the working directory to change into.
+ * @returns 0 on success, negative error code otherwise.
+ */
+int ceph_chdir(struct ceph_mount_info *cmount, const char *path);
+
+/** @} fsops */
+
+/**
+ * @defgroup libcephfs_h_dir Directory Operations.
+ * Functions for manipulating and listing directories.
+ *
+ * @{
+ */
+
+/**
+ * Open the given directory.
+ *
+ * @param cmount the ceph mount handle to use to open the directory
+ * @param name the path name of the directory to open.  Must be either an absolute path
+ *        or a path relative to the current working directory.
+ * @param dirpp the directory result pointer structure to fill in.
+ * @returns 0 on success or negative error code otherwise.
+ */
+int ceph_opendir(struct ceph_mount_info *cmount, const char *name, struct ceph_dir_result **dirpp);
+
+/**
+ * Open a directory referred to by a file descriptor
+ *
+ * @param cmount the ceph mount handle to use to open the directory
+ * @param dirfd open file descriptor for the directory
+ * @param dirpp the directory result pointer structure to fill in
+ * @returns 0 on success or negative error code otherwise
+ */
+int ceph_fdopendir(struct ceph_mount_info *cmount, int dirfd, struct ceph_dir_result **dirpp);
+
+/**
+ * Close the open directory.
+ *
+ * @param cmount the ceph mount handle to use for closing the directory
+ * @param dirp the directory result pointer (set by ceph_opendir) to close
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_closedir(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp);
+
+/**
+ * Get the next entry in an open directory.
+ *
+ * @param cmount the ceph mount handle to use for performing the readdir.
+ * @param dirp the directory stream pointer from an opendir holding the state of the
+ *        next entry to return.
+ * @returns the next directory entry or NULL if at the end of the directory (or the directory
+ *          is empty.  This pointer should not be freed by the caller, and is only safe to
+ *          access between return and the next call to ceph_readdir or ceph_closedir.
+ */
+struct dirent * ceph_readdir(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp);
+
+/**
+ * A safe version of ceph_readdir, where the directory entry struct is allocated by the caller.
+ *
+ * @param cmount the ceph mount handle to use for performing the readdir.
+ * @param dirp the directory stream pointer from an opendir holding the state of the
+ *        next entry to return.
+ * @param de the directory entry pointer filled in with the next directory entry of the dirp state.
+ * @returns 1 if the next entry was filled in, 0 if the end of the directory stream was reached,
+ *          and a negative error code on failure.
+ */
+int ceph_readdir_r(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp, struct dirent *de);
+
+/**
+ * A safe version of ceph_readdir that also returns the file statistics (readdir+stat).
+ *
+ * @param cmount the ceph mount handle to use for performing the readdir_plus_r.
+ * @param dirp the directory stream pointer from an opendir holding the state of the
+ *        next entry to return.
+ * @param de the directory entry pointer filled in with the next directory entry of the dirp state.
+ * @param stx the stats of the file/directory of the entry returned
+ * @param want mask showing desired inode attrs for returned entry
+ * @param flags bitmask of flags to use when filling out attributes
+ * @param out optional returned Inode argument. If non-NULL, then a reference will be taken on
+ *            the inode and the pointer set on success.
+ * @returns 1 if the next entry was filled in, 0 if the end of the directory stream was reached,
+ *          and a negative error code on failure.
+ */
+int ceph_readdirplus_r(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp, struct dirent *de,
+		       struct ceph_statx *stx, unsigned want, unsigned flags, struct Inode **out);
+
+struct ceph_snapdiff_info
+{
+  struct ceph_mount_info* cmount;
+  struct ceph_dir_result* dir1;    // primary dir entry to build snapdiff for.
+  struct ceph_dir_result* dir_aux; // aux dir entry to identify the second snapshot.
+                                   // Can point to the parent dir entry if entry-in-question
+                                   // doesn't exist in the second snapshot
+};
+
+/**
+ * Opens snapdiff stream to get snapshots delta (aka snapdiff).
+ *
+ * @param cmount the ceph mount handle to use for snapdiff retrieval.
+ * @param root_path  root path for snapshots-in-question
+ * @param rel_path subpath under the root to build delta for
+ * @param snap1 the first snapshot name
+ * @param snap2 the second snapshot name
+ * @param out resulting snapdiff stream handle to be used for snapdiff results
+              retrieval via ceph_readdir_snapdiff
+ * @returns 0 on success and negative error code otherwise
+ */
+int ceph_open_snapdiff(struct ceph_mount_info* cmount,
+                       const char* root_path,
+                       const char* rel_path,
+                       const char* snap1,
+                       const char* snap2,
+                       struct ceph_snapdiff_info* out);
+/**
+ * Get the next snapshot delta entry.
+ *
+ * @param info snapdiff stream handle opened via ceph_open_snapdiff()
+ * @param out  the next snapdiff entry which includes directory entry and the
+ *             entry's snapshot id - later one for emerged/existing entry or
+ *             former snapshot id for the removed entry.
+ * @returns >0 on success, 0 if no more entries in the stream and negative
+ *          error code otherwise
+ */
+int ceph_readdir_snapdiff(struct ceph_snapdiff_info* snapdiff,
+                          struct ceph_snapdiff_entry_t* out);
+/**
+ * Close snapdiff stream.
+ *
+ * @param info snapdiff stream handle opened via ceph_open_snapdiff()
+ * @returns 0 on success and negative error code otherwise
+ */
+int ceph_close_snapdiff(struct ceph_snapdiff_info* snapdiff);
+
+/**
+ * Gets multiple directory entries.
+ *
+ * @param cmount the ceph mount handle to use for performing the getdents.
+ * @param dirp the directory stream pointer from an opendir holding the state of the
+ *        next entry/entries to return.
+ * @param name an array of struct dirent that gets filled in with the  to fill returned directory entries into.
+ * @param buflen the length of the buffer, which should be the number of dirent structs * sizeof(struct dirent).
+ * @returns the length of the buffer that was filled in, will always be multiples of sizeof(struct dirent), or a
+ *          negative error code.  If the buffer is not large enough for a single entry, -ERANGE is returned.
+ */
+int ceph_getdents(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp, char *name, int buflen);
+
+/**
+ * Gets multiple directory names.
+ * 
+ * @param cmount the ceph mount handle to use for performing the getdents.
+ * @param dirp the directory stream pointer from an opendir holding the state of the
+ *        next entry/entries to return.
+ * @param name a buffer to fill in with directory entry names.
+ * @param buflen the length of the buffer that can be filled in.
+ * @returns the length of the buffer filled in with entry names, or a negative error code on failure.
+ *          If the buffer isn't large enough for a single entry, -ERANGE is returned.
+ */
+int ceph_getdnames(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp, char *name, int buflen);
+
+/**
+ * Rewind the directory stream to the beginning of the directory.
+ *
+ * @param cmount the ceph mount handle to use for performing the rewinddir.
+ * @param dirp the directory stream pointer to rewind.
+ */
+void ceph_rewinddir(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp);
+
+/**
+ * Get the current position of a directory stream.
+ *
+ * @param cmount the ceph mount handle to use for performing the telldir.
+ * @param dirp the directory stream pointer to get the current position of.
+ * @returns the position of the directory stream.  Note that the offsets returned
+ *          by ceph_telldir do not have a particular order (cannot be compared with
+ *          inequality).
+ */
+int64_t ceph_telldir(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp);
+
+/**
+ * Move the directory stream to a position specified by the given offset.
+ *
+ * @param cmount the ceph mount handle to use for performing the seekdir.
+ * @param dirp the directory stream pointer to move.
+ * @param offset the position to move the directory stream to.  This offset should be
+ *        a value returned by telldir.  Note that this value does not refer to the nth
+ *        entry in a directory, and can not be manipulated with plus or minus.
+ */
+void ceph_seekdir(struct ceph_mount_info *cmount, struct ceph_dir_result *dirp, int64_t offset);
+
+/**
+ * Create a directory.
+ *
+ * @param cmount the ceph mount handle to use for making the directory.
+ * @param path the path of the directory to create.  This must be either an
+ *        absolute path or a relative path off of the current working directory.
+ * @param mode the permissions the directory should have once created.
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_mkdir(struct ceph_mount_info *cmount, const char *path, mode_t mode);
+
+/**
+ * Create a directory relative to a file descriptor
+ *
+ * @param cmount the ceph mount handle to use for making the directory.
+ * @param dirfd open file descriptor for a directory (or CEPHFS_AT_FDCWD)
+ * @param relpath the path of the directory to create.
+ * @param mode the permissions the directory should have once created.
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_mkdirat(struct ceph_mount_info *cmount, int dirfd, const char *relpath, mode_t mode);
+
+/**
+ * Create a snapshot
+ *
+ * @param cmount the ceph mount handle to use for making the directory.
+ * @param path the path of the directory to create snapshot.  This must be either an
+ *        absolute path or a relative path off of the current working directory.
+ * @param name snapshot name
+ * @param mode the permissions the directory should have once created.
+ * @param snap_metadata array of snap metadata structs
+ * @param nr_snap_metadata number of snap metadata struct entries
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_mksnap(struct ceph_mount_info *cmount, const char *path, const char *name,
+                mode_t mode, struct snap_metadata *snap_metadata, size_t nr_snap_metadata);
+
+/**
+ * Remove a snapshot
+ *
+ * @param cmount the ceph mount handle to use for making the directory.
+ * @param path the path of the directory to create snapshot.  This must be either an
+ *        absolute path or a relative path off of the current working directory.
+ * @param name snapshot name
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_rmsnap(struct ceph_mount_info *cmount, const char *path, const char *name);
+
+/**
+ * Create multiple directories at once.
+ *
+ * @param cmount the ceph mount handle to use for making the directories.
+ * @param path the full path of directories and sub-directories that should
+ *        be created.
+ * @param mode the permissions the directory should have once created.
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_mkdirs(struct ceph_mount_info *cmount, const char *path, mode_t mode);
+
+/**
+ * Remove a directory.
+ *
+ * @param cmount the ceph mount handle to use for removing directories.
+ * @param path the path of the directory to remove.
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_rmdir(struct ceph_mount_info *cmount, const char *path);
+
+/** @} dir */
+
+/**
+ * @defgroup libcephfs_h_links Links and Link Handling.
+ * Functions for creating and manipulating hard links and symbolic inks.
+ *
+ * @{
+ */
+
+/**
+ * Create a link.
+ *
+ * @param cmount the ceph mount handle to use for creating the link.
+ * @param existing the path to the existing file/directory to link to.
+ * @param newname the path to the new file/directory to link from.
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_link(struct ceph_mount_info *cmount, const char *existing, const char *newname);
+
+/**
+ * Read a symbolic link.
+ *
+ * @param cmount the ceph mount handle to use for creating the link.
+ * @param path the path to the symlink to read
+ * @param buf the buffer to hold the path of the file that the symlink points to.
+ * @param size the length of the buffer
+ * @returns number of bytes copied on success or negative error code on failure
+ */
+int ceph_readlink(struct ceph_mount_info *cmount, const char *path, char *buf, int64_t size);
+
+/**
+ * Read a symbolic link relative to a file descriptor
+ *
+ * @param cmount the ceph mount handle to use for creating the link.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param relpath the path to the symlink to read
+ * @param buf the buffer to hold the path of the file that the symlink points to.
+ * @param size the length of the buffer
+ * @returns number of bytes copied on success or negative error code on failure
+ */
+int ceph_readlinkat(struct ceph_mount_info *cmount, int dirfd, const char *relpath, char *buf,
+                    int64_t size);
+
+/**
+ * Creates a symbolic link.
+ *
+ * @param cmount the ceph mount handle to use for creating the symbolic link.
+ * @param existing the path to the existing file/directory to link to.
+ * @param newname the path to the new file/directory to link from.
+ * @returns 0 on success or a negative return code on failure.
+ */
+int ceph_symlink(struct ceph_mount_info *cmount, const char *existing, const char *newname);
+
+/**
+ * Creates a symbolic link relative to a file descriptor
+ *
+ * @param cmount the ceph mount handle to use for creating the symbolic link.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param existing the path to the existing file/directory to link to.
+ * @param newname the path to the new file/directory to link from.
+ * @returns 0 on success or a negative return code on failure.
+ */
+int ceph_symlinkat(struct ceph_mount_info *cmount, const char *existing, int dirfd,
+                   const char *newname);
+
+/** @} links */
+
+/**
+ * @defgroup libcephfs_h_files File manipulation and handling.
+ * Functions for creating and manipulating files.
+ *
+ * @{
+ */
+
+
+/**
+ * Checks if deleting a file, link or directory is allowed.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file, link or directory.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_may_delete(struct ceph_mount_info *cmount, const char *path);
+
+/**
+ * Removes a file, link, or symbolic link.  If the file/link has multiple links to it, the
+ * file will not disappear from the namespace until all references to it are removed.
+ * 
+ * @param cmount the ceph mount handle to use for performing the unlink.
+ * @param path the path of the file or link to unlink.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_unlink(struct ceph_mount_info *cmount, const char *path);
+
+/**
+ * Removes a file, link, or symbolic link relative to a file descriptor.
+ * If the file/link has multiple links to it, the file will not
+ * disappear from the namespace until all references to it are removed.
+ *
+ * @param cmount the ceph mount handle to use for performing the unlink.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param relpath the path of the file or link to unlink.
+ * @param flags bitfield that can be used to set AT_* modifier flags (only AT_REMOVEDIR)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_unlinkat(struct ceph_mount_info *cmount, int dirfd, const char *relpath, int flags);
+
+/**
+ * Rename a file or directory.
+ *
+ * @param cmount the ceph mount handle to use for performing the rename.
+ * @param from the path to the existing file or directory.
+ * @param to the new name of the file or directory
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_rename(struct ceph_mount_info *cmount, const char *from, const char *to);
+
+/**
+ * Get an open file's extended statistics and attributes.
+ *
+ * @param cmount the ceph mount handle to use for performing the stat.
+ * @param fd the file descriptor of the file to get statistics of.
+ * @param stx the ceph_statx struct that will be filled in with the file's statistics.
+ * @param want bitfield of CEPH_STATX_* flags showing designed attributes
+ * @param flags bitfield that can be used to set AT_* modifier flags (AT_STATX_SYNC_AS_STAT, AT_STATX_FORCE_SYNC, AT_STATX_DONT_SYNC and AT_SYMLINK_NOFOLLOW)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_fstatx(struct ceph_mount_info *cmount, int fd, struct ceph_statx *stx,
+		unsigned int want, unsigned int flags);
+
+/**
+ * Get attributes of a file relative to a file descriptor
+ *
+ * @param cmount the ceph mount handle to use for performing the stat.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param relpath to the file/directory to get statistics of
+ * @param stx the ceph_statx struct that will be filled in with the file's statistics.
+ * @param want bitfield of CEPH_STATX_* flags showing designed attributes
+ * @param flags bitfield that can be used to set AT_* modifier flags (AT_STATX_SYNC_AS_STAT, AT_STATX_FORCE_SYNC, AT_STATX_DONT_SYNC and AT_SYMLINK_NOFOLLOW)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_statxat(struct ceph_mount_info *cmount, int dirfd, const char *relpath,
+                 struct ceph_statx *stx, unsigned int want, unsigned int flags);
+
+/**
+ * Get a file's extended statistics and attributes.
+ *
+ * @param cmount the ceph mount handle to use for performing the stat.
+ * @param path the file or directory to get the statistics of.
+ * @param stx the ceph_statx struct that will be filled in with the file's statistics.
+ * @param want bitfield of CEPH_STATX_* flags showing designed attributes
+ * @param flags bitfield that can be used to set AT_* modifier flags (AT_STATX_SYNC_AS_STAT, AT_STATX_FORCE_SYNC, AT_STATX_DONT_SYNC and AT_SYMLINK_NOFOLLOW)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_statx(struct ceph_mount_info *cmount, const char *path, struct ceph_statx *stx,
+	       unsigned int want, unsigned int flags);
+
+/**
+ * Get a file's statistics and attributes.
+ *
+ * ceph_stat() is deprecated, use ceph_statx() instead.
+ *
+ * @param cmount the ceph mount handle to use for performing the stat.
+ * @param path the file or directory to get the statistics of.
+ * @param stbuf the stat struct that will be filled in with the file's statistics.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_stat(struct ceph_mount_info *cmount, const char *path, struct stat *stbuf)
+  LIBCEPHFS_DEPRECATED;
+
+/**
+ * Get a file's statistics and attributes, without following symlinks.
+ *
+ * ceph_lstat() is deprecated, use ceph_statx(.., AT_SYMLINK_NOFOLLOW) instead.
+ *
+ * @param cmount the ceph mount handle to use for performing the stat.
+ * @param path the file or directory to get the statistics of.
+ * @param stbuf the stat struct that will be filled in with the file's statistics.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_lstat(struct ceph_mount_info *cmount, const char *path, struct stat *stbuf)
+  LIBCEPHFS_DEPRECATED;
+
+/**
+ * Get the open file's statistics.
+ *
+ * ceph_fstat() is deprecated, use ceph_fstatx() instead.
+ *
+ * @param cmount the ceph mount handle to use for performing the fstat.
+ * @param fd the file descriptor of the file to get statistics of.
+ * @param stbuf the stat struct of the file's statistics, filled in by the
+ *    function.
+ * @returns 0 on success or a negative error code on failure
+ */
+int ceph_fstat(struct ceph_mount_info *cmount, int fd, struct stat *stbuf)
+  LIBCEPHFS_DEPRECATED;
+
+/**
+ * Set a file's attributes.
+ *
+ * @param cmount the ceph mount handle to use for performing the setattr.
+ * @param relpath the path to the file/directory to set the attributes of.
+ * @param stx the statx struct that must include attribute values to set on the file.
+ * @param mask a mask of all the CEPH_SETATTR_* values that have been set in the statx struct.
+ * @param flags mask of AT_* flags (only AT_ATTR_NOFOLLOW is respected for now)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_setattrx(struct ceph_mount_info *cmount, const char *relpath, struct ceph_statx *stx, int mask, int flags);
+
+/**
+ * Set a file's attributes (extended version).
+ * 
+ * @param cmount the ceph mount handle to use for performing the setattr.
+ * @param fd the fd of the open file/directory to set the attributes of.
+ * @param stx the statx struct that must include attribute values to set on the file.
+ * @param mask a mask of all the stat values that have been set on the stat struct.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_fsetattrx(struct ceph_mount_info *cmount, int fd, struct ceph_statx *stx, int mask);
+
+/**
+ * Change the mode bits (permissions) of a file/directory.
+ *
+ * @param cmount the ceph mount handle to use for performing the chmod.
+ * @param path the path to the file/directory to change the mode bits on.
+ * @param mode the new permissions to set.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_chmod(struct ceph_mount_info *cmount, const char *path, mode_t mode);
+
+/**
+ * Change the mode bits (permissions) of a file/directory. If the path is a
+ * symbolic link, it's not de-referenced.
+ *
+ * @param cmount the ceph mount handle to use for performing the chmod.
+ * @param path the path of file/directory to change the mode bits on.
+ * @param mode the new permissions to set.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_lchmod(struct ceph_mount_info *cmount, const char *path, mode_t mode);
+
+/**
+ * Change the mode bits (permissions) of an open file.
+ *
+ * @param cmount the ceph mount handle to use for performing the chmod.
+ * @param fd the open file descriptor to change the mode bits on.
+ * @param mode the new permissions to set.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_fchmod(struct ceph_mount_info *cmount, int fd, mode_t mode);
+
+/**
+ * Change the mode bits (permissions) of a file relative to a file descriptor.
+ *
+ * @param cmount the ceph mount handle to use for performing the chown.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param relpath the relpath of the file/directory to change the ownership of.
+ * @param mode the new permissions to set.
+ * @param flags bitfield that can be used to set AT_* modifier flags (AT_SYMLINK_NOFOLLOW)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_chmodat(struct ceph_mount_info *cmount, int dirfd, const char *relpath,
+                 mode_t mode, int flags);
+
+/**
+ * Change the ownership of a file/directory.
+ * 
+ * @param cmount the ceph mount handle to use for performing the chown.
+ * @param path the path of the file/directory to change the ownership of.
+ * @param uid the user id to set on the file/directory.
+ * @param gid the group id to set on the file/directory.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_chown(struct ceph_mount_info *cmount, const char *path, int uid, int gid);
+
+/**
+ * Change the ownership of a file from an open file descriptor.
+ *
+ * @param cmount the ceph mount handle to use for performing the chown.
+ * @param fd the fd of the open file/directory to change the ownership of.
+ * @param uid the user id to set on the file/directory.
+ * @param gid the group id to set on the file/directory.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_fchown(struct ceph_mount_info *cmount, int fd, int uid, int gid);
+
+/**
+ * Change the ownership of a file/directory, don't follow symlinks.
+ * 
+ * @param cmount the ceph mount handle to use for performing the chown.
+ * @param path the path of the file/directory to change the ownership of.
+ * @param uid the user id to set on the file/directory.
+ * @param gid the group id to set on the file/directory.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_lchown(struct ceph_mount_info *cmount, const char *path, int uid, int gid);
+
+/**
+ * Change the ownership of a file/directory releative to a file descriptor.
+ *
+ * @param cmount the ceph mount handle to use for performing the chown.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param relpath the relpath of the file/directory to change the ownership of.
+ * @param uid the user id to set on the file/directory.
+ * @param gid the group id to set on the file/directory.
+ * @param flags bitfield that can be used to set AT_* modifier flags (AT_SYMLINK_NOFOLLOW)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_chownat(struct ceph_mount_info *cmount, int dirfd, const char *relpath,
+                 uid_t uid, gid_t gid, int flags);
+
+/**
+ * Change file/directory last access and modification times.
+ *
+ * @param cmount the ceph mount handle to use for performing the utime.
+ * @param path the path to the file/directory to set the time values of.
+ * @param buf holding the access and modification times to set on the file.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_utime(struct ceph_mount_info *cmount, const char *path, struct utimbuf *buf);
+
+/**
+ * Change file/directory last access and modification times.
+ *
+ * @param cmount the ceph mount handle to use for performing the utime.
+ * @param fd the fd of the open file/directory to set the time values of.
+ * @param buf holding the access and modification times to set on the file.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_futime(struct ceph_mount_info *cmount, int fd, struct utimbuf *buf);
+
+/**
+ * Change file/directory last access and modification times.
+ *
+ * @param cmount the ceph mount handle to use for performing the utime.
+ * @param path the path to the file/directory to set the time values of.
+ * @param times holding the access and modification times to set on the file.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_utimes(struct ceph_mount_info *cmount, const char *path, struct timeval times[2]);
+
+/**
+ * Change file/directory last access and modification times, don't follow symlinks.
+ *
+ * @param cmount the ceph mount handle to use for performing the utime.
+ * @param path the path to the file/directory to set the time values of.
+ * @param times holding the access and modification times to set on the file.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_lutimes(struct ceph_mount_info *cmount, const char *path, struct timeval times[2]);
+
+/**
+ * Change file/directory last access and modification times.
+ *
+ * @param cmount the ceph mount handle to use for performing the utime.
+ * @param fd the fd of the open file/directory to set the time values of.
+ * @param times holding the access and modification times to set on the file.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_futimes(struct ceph_mount_info *cmount, int fd, struct timeval times[2]);
+
+/**
+ * Change file/directory last access and modification times.
+ *
+ * @param cmount the ceph mount handle to use for performing the utime.
+ * @param fd the fd of the open file/directory to set the time values of.
+ * @param times holding the access and modification times to set on the file.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_futimens(struct ceph_mount_info *cmount, int fd, struct timespec times[2]);
+
+/**
+ * Change file/directory last access and modification times relative
+ * to a file descriptor.
+ *
+ * @param cmount the ceph mount handle to use for performing the utime.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param relpath the relpath of the file/directory to change the ownership of.
+ * @param dirfd the fd of the open file/directory to set the time values of.
+ * @param times holding the access and modification times to set on the file.
+ * @param flags bitfield that can be used to set AT_* modifier flags (AT_SYMLINK_NOFOLLOW)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_utimensat(struct ceph_mount_info *cmount, int dirfd, const char *relpath,
+                   struct timespec times[2], int flags);
+
+/**
+ * Apply or remove an advisory lock.
+ *
+ * @param cmount the ceph mount handle to use for performing the lock.
+ * @param fd the open file descriptor to change advisory lock.
+ * @param operation the advisory lock operation to be performed on the file
+ * descriptor among LOCK_SH (shared lock), LOCK_EX (exclusive lock),
+ * or LOCK_UN (remove lock). The LOCK_NB value can be ORed to perform a
+ * non-blocking operation.
+ * @param owner the user-supplied owner identifier (an arbitrary integer)
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_flock(struct ceph_mount_info *cmount, int fd, int operation,
+	       uint64_t owner);
+
+/**
+ * Truncate the file to the given size.  If this operation causes the
+ * file to expand, the empty bytes will be filled in with zeros.
+ *
+ * @param cmount the ceph mount handle to use for performing the truncate.
+ * @param path the path to the file to truncate.
+ * @param size the new size of the file.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_truncate(struct ceph_mount_info *cmount, const char *path, int64_t size);
+
+/**
+ * Make a block or character special file.
+ *
+ * @param cmount the ceph mount handle to use for performing the mknod.
+ * @param path the path to the special file.
+ * @param mode the permissions to use and the type of special file.  The type can be
+ *        one of S_IFREG, S_IFCHR, S_IFBLK, S_IFIFO.
+ * @param rdev If the file type is S_IFCHR or S_IFBLK then this parameter specifies the
+ *        major and minor numbers of the newly created device special file.  Otherwise, 
+ *        it is ignored.
+ * @returns 0 on success or negative error code on failure.
+ */
+int ceph_mknod(struct ceph_mount_info *cmount, const char *path, mode_t mode, dev_t rdev);
+/**
+ * Create and/or open a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the open.
+ * @param path the path of the file to open.  If the flags parameter includes O_CREAT,
+ *        the file will first be created before opening.
+ * @param flags a set of option masks that control how the file is created/opened.
+ * @param mode the permissions to place on the file if the file does not exist and O_CREAT
+ *        is specified in the flags.
+ * @returns a non-negative file descriptor number on success or a negative error code on failure.
+ */
+int ceph_open(struct ceph_mount_info *cmount, const char *path, int flags, mode_t mode);
+
+/**
+ * Create and/or open a file relative to a directory
+ *
+ * @param cmount the ceph mount handle to use for performing the open.
+ * @param dirfd open file descriptor (or CEPHFS_AT_FDCWD)
+ * @param relpath the path of the file to open.  If the flags parameter includes O_CREAT,
+ *        the file will first be created before opening.
+ * @param flags a set of option masks that control how the file is created/opened.
+ * @param mode the permissions to place on the file if the file does not exist and O_CREAT
+ *        is specified in the flags.
+ * @returns a non-negative file descriptor number on success or a negative error code on failure.
+ */
+int ceph_openat(struct ceph_mount_info *cmount, int dirfd, const char *relpath, int flags, mode_t mode);
+
+/**
+ * Create and/or open a file with a specific file layout.
+ *
+ * @param cmount the ceph mount handle to use for performing the open.
+ * @param path the path of the file to open.  If the flags parameter includes O_CREAT,
+ *        the file will first be created before opening.
+ * @param flags a set of option masks that control how the file is created/opened.
+ * @param mode the permissions to place on the file if the file does not exist and O_CREAT
+ *        is specified in the flags.
+ * @param stripe_unit the stripe unit size (option, 0 for default)
+ * @param stripe_count the stripe count (optional, 0 for default)
+ * @param object_size the object size (optional, 0 for default)
+ * @param data_pool name of target data pool name (optional, NULL or empty string for default)
+ * @returns a non-negative file descriptor number on success or a negative error code on failure.
+ */
+int ceph_open_layout(struct ceph_mount_info *cmount, const char *path, int flags,
+ 		     mode_t mode, int stripe_unit, int stripe_count, int object_size,
+ 		     const char *data_pool);
+
+/**
+ * Close the open file.
+ *
+ * @param cmount the ceph mount handle to use for performing the close.
+ * @param fd the file descriptor referring to the open file.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_close(struct ceph_mount_info *cmount, int fd);
+
+/**
+ * Reposition the open file stream based on the given offset.
+ *
+ * @param cmount the ceph mount handle to use for performing the lseek.
+ * @param fd the open file descriptor referring to the open file and holding the
+ *        current position of the stream.
+ * @param offset the offset to set the stream to
+ * @param whence the flag to indicate what type of seeking to perform:
+ *	SEEK_SET: the offset is set to the given offset in the file.
+ *      SEEK_CUR: the offset is set to the current location plus @e offset bytes.
+ *      SEEK_END: the offset is set to the end of the file plus @e offset bytes.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int64_t ceph_lseek(struct ceph_mount_info *cmount, int fd, int64_t offset, int whence);
+/**
+ * Read data from the file.
+ *
+ * @param cmount the ceph mount handle to use for performing the read.
+ * @param fd the file descriptor of the open file to read from.
+ * @param buf the buffer to read data into
+ * @param size the initial size of the buffer
+ * @param offset the offset in the file to read from.  If this value is negative, the
+ *        function reads from the current offset of the file descriptor.
+ * @returns the number of bytes read into buf, or a negative error code on failure.
+ */
+int ceph_read(struct ceph_mount_info *cmount, int fd, char *buf, int64_t size, int64_t offset);
+
+/**
+ * Read data from the file.
+ * @param cmount the ceph mount handle to use for performing the read.
+ * @param fd the file descriptor of the open file to read from.
+ * @param iov the iov structure to read data into
+ * @param iovcnt the number of items that iov includes
+ * @param offset the offset in the file to read from.  If this value is negative, the
+ *        function reads from the current offset of the file descriptor.
+ * @returns the number of bytes read into buf, or a negative error code on failure.
+ */
+int ceph_preadv(struct ceph_mount_info *cmount, int fd, const struct iovec *iov, int iovcnt,
+           int64_t offset);
+
+/**
+ * Write data to a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the write.
+ * @param fd the file descriptor of the open file to write to
+ * @param buf the bytes to write to the file
+ * @param size the size of the buf array
+ * @param offset the offset of the file write into.  If this value is negative, the
+ *        function writes to the current offset of the file descriptor.
+ * @returns the number of bytes written, or a negative error code
+ */
+int ceph_write(struct ceph_mount_info *cmount, int fd, const char *buf, int64_t size,
+	       int64_t offset);
+
+/**
+ * Write data to a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the write.
+ * @param fd the file descriptor of the open file to write to
+ * @param iov the iov structure to read data into
+ * @param iovcnt the number of items that iov includes
+ * @param offset the offset of the file write into.  If this value is negative, the
+ *        function writes to the current offset of the file descriptor.
+ * @returns the number of bytes written, or a negative error code
+ */
+int ceph_pwritev(struct ceph_mount_info *cmount, int fd, const struct iovec *iov, int iovcnt,
+           int64_t offset);
+
+/**
+ * Truncate a file to the given size.
+ *
+ * @param cmount the ceph mount handle to use for performing the ftruncate.
+ * @param fd the file descriptor of the file to truncate
+ * @param size the new size of the file
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_ftruncate(struct ceph_mount_info *cmount, int fd, int64_t size);
+
+/**
+ * Synchronize an open file to persistent media.
+ *
+ * @param cmount the ceph mount handle to use for performing the fsync.
+ * @param fd the file descriptor of the file to sync.
+ * @param syncdataonly a boolean whether to synchronize metadata and data (0)
+ *        or just data (1).
+ * @return 0 on success or a negative error code on failure.
+ */
+int ceph_fsync(struct ceph_mount_info *cmount, int fd, int syncdataonly);
+
+/**
+ * Preallocate or release disk space for the file for the byte range.
+ *
+ * @param cmount the ceph mount handle to use for performing the fallocate.
+ * @param fd the file descriptor of the file to fallocate.
+ * @param mode the flags determines the operation to be performed on the given range.
+ *        default operation (0) allocate and initialize to zero the file in the byte range,
+ *        and the file size will be changed if offset + length is greater than
+ *        the file size. if the FALLOC_FL_KEEP_SIZE flag is specified in the mode,
+ *        the file size will not be changed. if the FALLOC_FL_PUNCH_HOLE flag is
+ *        specified in the mode, the operation is deallocate space and zero the byte range.
+ * @param offset the byte range starting.
+ * @param length the length of the range.
+ * @return 0 on success or a negative error code on failure.
+ */
+int ceph_fallocate(struct ceph_mount_info *cmount, int fd, int mode,
+	                      int64_t offset, int64_t length);
+
+/**
+ * Enable/disable lazyio for the file.
+ *
+ * @param cmount the ceph mount handle to use for performing the fsync.
+ * @param fd the file descriptor of the file to sync.
+ * @param enable a boolean to enable lazyio or disable lazyio.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_lazyio(struct ceph_mount_info *cmount, int fd, int enable);
+
+
+/**
+ * Flushes the write buffer for the file thereby propogating the buffered write to the file.
+ *
+ * @param cmount the ceph mount handle to use for performing the fsync.
+ * @param fd the file descriptor of the file to sync.
+ * @param offset a boolean to enable lazyio or disable lazyio.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_lazyio_propagate(struct ceph_mount_info *cmount, int fd, int64_t offset, size_t count);
+
+
+/**
+ * Flushes the write buffer for the file and invalidate the read cache. This allows a subsequent read operation to read and cache data directly from the file and hence everyone's propagated writes would be visible. 
+ *
+ * @param cmount the ceph mount handle to use for performing the fsync.
+ * @param fd the file descriptor of the file to sync.
+ * @param offset a boolean to enable lazyio or disable lazyio.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_lazyio_synchronize(struct ceph_mount_info *cmount, int fd, int64_t offset, size_t count);
+
+/** @} file */
+
+/**
+ * @defgroup libcephfs_h_xattr Extended Attribute manipulation and handling.
+ * Functions for creating and manipulating extended attributes on files.
+ *
+ * @{
+ */
+
+/**
+ * Get an extended attribute.
+ *
+ * @param cmount the ceph mount handle to use for performing the getxattr.
+ * @param path the path to the file
+ * @param name the name of the extended attribute to get
+ * @param value a pre-allocated buffer to hold the xattr's value
+ * @param size the size of the pre-allocated buffer
+ * @returns the size of the value or a negative error code on failure.
+ */
+int ceph_getxattr(struct ceph_mount_info *cmount, const char *path, const char *name, 
+	void *value, size_t size);
+
+/**
+ * Get an extended attribute.
+ *
+ * @param cmount the ceph mount handle to use for performing the getxattr.
+ * @param fd the open file descriptor referring to the file to get extended attribute from.
+ * @param name the name of the extended attribute to get
+ * @param value a pre-allocated buffer to hold the xattr's value
+ * @param size the size of the pre-allocated buffer
+ * @returns the size of the value or a negative error code on failure.
+ */
+int ceph_fgetxattr(struct ceph_mount_info *cmount, int fd, const char *name,
+	void *value, size_t size);
+
+/**
+ * Get an extended attribute without following symbolic links.  This function is
+ * identical to ceph_getxattr, but if the path refers to a symbolic link,
+ * we get the extended attributes of the symlink rather than the attributes
+ * of the link itself.
+ *
+ * @param cmount the ceph mount handle to use for performing the lgetxattr.
+ * @param path the path to the file
+ * @param name the name of the extended attribute to get
+ * @param value a pre-allocated buffer to hold the xattr's value
+ * @param size the size of the pre-allocated buffer
+ * @returns the size of the value or a negative error code on failure.
+ */
+int ceph_lgetxattr(struct ceph_mount_info *cmount, const char *path, const char *name, 
+	void *value, size_t size);
+
+/**
+ * List the extended attribute keys on a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the listxattr.
+ * @param path the path to the file.
+ * @param list a buffer to be filled in with the list of extended attributes keys.
+ * @param size the size of the list buffer.
+ * @returns the size of the resulting list filled in.
+ */
+int ceph_listxattr(struct ceph_mount_info *cmount, const char *path, char *list, size_t size);
+
+/**
+ * List the extended attribute keys on a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the listxattr.
+ * @param fd the open file descriptor referring to the file to list extended attributes on.
+ * @param list a buffer to be filled in with the list of extended attributes keys.
+ * @param size the size of the list buffer.
+ * @returns the size of the resulting list filled in.
+ */
+int ceph_flistxattr(struct ceph_mount_info *cmount, int fd, char *list, size_t size);
+
+/**
+ * Get the list of extended attribute keys on a file, but do not follow symbolic links.
+ *
+ * @param cmount the ceph mount handle to use for performing the llistxattr.
+ * @param path the path to the file.
+ * @param list a buffer to be filled in with the list of extended attributes keys.
+ * @param size the size of the list buffer.
+ * @returns the size of the resulting list filled in.
+ */
+int ceph_llistxattr(struct ceph_mount_info *cmount, const char *path, char *list, size_t size);
+
+/**
+ * Remove an extended attribute from a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the removexattr.
+ * @param path the path to the file.
+ * @param name the name of the extended attribute to remove.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_removexattr(struct ceph_mount_info *cmount, const char *path, const char *name);
+
+/**
+ * Remove an extended attribute from a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the removexattr.
+ * @param fd the open file descriptor referring to the file to remove extended attribute from.
+ * @param name the name of the extended attribute to remove.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_fremovexattr(struct ceph_mount_info *cmount, int fd, const char *name);
+
+/**
+ * Remove the extended attribute from a file, do not follow symbolic links.
+ *
+ * @param cmount the ceph mount handle to use for performing the lremovexattr.
+ * @param path the path to the file.
+ * @param name the name of the extended attribute to remove.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_lremovexattr(struct ceph_mount_info *cmount, const char *path, const char *name);
+
+/**
+ * Set an extended attribute on a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the setxattr.
+ * @param path the path to the file.
+ * @param name the name of the extended attribute to set.
+ * @param value the bytes of the extended attribute value
+ * @param size the size of the extended attribute value
+ * @param flags the flags can be:
+ *	CEPH_XATTR_CREATE: create the extended attribute.  Must not exist.
+ *      CEPH_XATTR_REPLACE: replace the extended attribute, Must already exist.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_setxattr(struct ceph_mount_info *cmount, const char *path, const char *name, 
+	const void *value, size_t size, int flags);
+
+/**
+ * Set an extended attribute on a file.
+ *
+ * @param cmount the ceph mount handle to use for performing the setxattr.
+ * @param fd the open file descriptor referring to the file to set extended attribute on.
+ * @param name the name of the extended attribute to set.
+ * @param value the bytes of the extended attribute value
+ * @param size the size of the extended attribute value
+ * @param flags the flags can be:
+ *	CEPH_XATTR_CREATE: create the extended attribute.  Must not exist.
+ *      CEPH_XATTR_REPLACE: replace the extended attribute, Must already exist.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_fsetxattr(struct ceph_mount_info *cmount, int fd, const char *name,
+	const void *value, size_t size, int flags);
+
+/**
+ * Set an extended attribute on a file, do not follow symbolic links.
+ *
+ * @param cmount the ceph mount handle to use for performing the lsetxattr.
+ * @param path the path to the file.
+ * @param name the name of the extended attribute to set.
+ * @param value the bytes of the extended attribute value
+ * @param size the size of the extended attribute value
+ * @param flags the flags can be:
+ *	CEPH_XATTR_CREATE: create the extended attribute.  Must not exist.
+ *      CEPH_XATTR_REPLACE: replace the extended attribute, Must already exist.
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_lsetxattr(struct ceph_mount_info *cmount, const char *path, const char *name, 
+	const void *value, size_t size, int flags);
+
+/** @} xattr */
+
+/**
+ * @defgroup libcephfs_h_filelayout Control File Layout.
+ * Functions for setting and getting the file layout of existing files.
+ *
+ * @{
+ */
+
+/**
+ * Get the file striping unit from an open file descriptor.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fh the open file descriptor referring to the file to get the striping unit of.
+ * @returns the striping unit of the file or a negative error code on failure.
+ */
+int ceph_get_file_stripe_unit(struct ceph_mount_info *cmount, int fh);
+
+/**
+ * Get the file striping unit.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file/directory get the striping unit of.
+ * @returns the striping unit of the file or a negative error code on failure.
+ */
+int ceph_get_path_stripe_unit(struct ceph_mount_info *cmount, const char *path);
+
+/**
+ * Get the file striping count from an open file descriptor.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fh the open file descriptor referring to the file to get the striping count of.
+ * @returns the striping count of the file or a negative error code on failure.
+ */
+int ceph_get_file_stripe_count(struct ceph_mount_info *cmount, int fh);
+
+/**
+ * Get the file striping count.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file/directory get the striping count of.
+ * @returns the striping count of the file or a negative error code on failure.
+ */
+int ceph_get_path_stripe_count(struct ceph_mount_info *cmount, const char *path);
+
+/**
+ * Get the file object size from an open file descriptor.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fh the open file descriptor referring to the file to get the object size of.
+ * @returns the object size of the file or a negative error code on failure.
+ */
+int ceph_get_file_object_size(struct ceph_mount_info *cmount, int fh);
+
+/**
+ * Get the file object size.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file/directory get the object size of.
+ * @returns the object size of the file or a negative error code on failure.
+ */
+int ceph_get_path_object_size(struct ceph_mount_info *cmount, const char *path);
+
+/**
+ * Get the file pool information from an open file descriptor.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fh the open file descriptor referring to the file to get the pool information of.
+ * @returns the ceph pool id that the file is in
+ */
+int ceph_get_file_pool(struct ceph_mount_info *cmount, int fh);
+
+/**
+ * Get the file pool information.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file/directory get the pool information of.
+ * @returns the ceph pool id that the file is in
+ */
+int ceph_get_path_pool(struct ceph_mount_info *cmount, const char *path);
+
+/**
+ * Get the name of the pool a opened file is stored in,
+ *
+ * Write the name of the file's pool to the buffer.  If buflen is 0, return
+ * a suggested length for the buffer.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fh the open file descriptor referring to the file
+ * @param buf buffer to store the name in
+ * @param buflen size of the buffer
+ * @returns length in bytes of the pool name, or -ERANGE if the buffer is not large enough.
+ */
+int ceph_get_file_pool_name(struct ceph_mount_info *cmount, int fh, char *buf, size_t buflen);
+
+/**
+ * get the name of a pool by id
+ *
+ * Given a pool's numeric identifier, get the pool's alphanumeric name.
+ *
+ * @param cmount the ceph mount handle to use
+ * @param pool the numeric pool id
+ * @param buf buffer to sore the name in
+ * @param buflen size of the buffer
+ * @returns length in bytes of the pool name, or -ERANGE if the buffer is not large enough
+ */
+int ceph_get_pool_name(struct ceph_mount_info *cmount, int pool, char *buf, size_t buflen);
+
+/**
+ * Get the name of the pool a file is stored in
+ *
+ * Write the name of the file's pool to the buffer.  If buflen is 0, return
+ * a suggested length for the buffer.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file/directory
+ * @param buf buffer to store the name in
+ * @param buflen size of the buffer
+ * @returns length in bytes of the pool name, or -ERANGE if the buffer is not large enough.
+ */
+int ceph_get_path_pool_name(struct ceph_mount_info *cmount, const char *path, char *buf, size_t buflen);
+
+/**
+ * Get the default pool name of cephfs
+ * Write the name of the default pool to the buffer. If buflen is 0, return
+ * a suggested length for the buffer.
+ * @param cmount the ceph mount handle to use.
+ * @param buf buffer to store the name in
+ * @param buflen size of the buffer
+ * @returns length in bytes of the pool name, or -ERANGE if the buffer is not large enough.
+ */
+int ceph_get_default_data_pool_name(struct ceph_mount_info *cmount, char *buf, size_t buflen);
+
+/**
+ * Get the file layout from an open file descriptor.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fh the open file descriptor referring to the file to get the layout of.
+ * @param stripe_unit where to store the striping unit of the file
+ * @param stripe_count where to store the striping count of the file
+ * @param object_size where to store the object size of the file
+ * @param pg_pool where to store the ceph pool id that the file is in
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_get_file_layout(struct ceph_mount_info *cmount, int fh, int *stripe_unit, int *stripe_count, int *object_size, int *pg_pool);
+
+/**
+ * Get the file layout.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file/directory get the layout of.
+ * @param stripe_unit where to store the striping unit of the file
+ * @param stripe_count where to store the striping count of the file
+ * @param object_size where to store the object size of the file
+ * @param pg_pool where to store the ceph pool id that the file is in
+ * @returns 0 on success or a negative error code on failure.
+ */
+int ceph_get_path_layout(struct ceph_mount_info *cmount, const char *path, int *stripe_unit, int *stripe_count, int *object_size, int *pg_pool);
+
+/**
+ * Get the file replication information from an open file descriptor.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fh the open file descriptor referring to the file to get the replication information of.
+ * @returns the replication factor of the file.
+ */
+int ceph_get_file_replication(struct ceph_mount_info *cmount, int fh);
+
+/**
+ * Get the file replication information.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path of the file/directory get the replication information of.
+ * @returns the replication factor of the file.
+ */
+int ceph_get_path_replication(struct ceph_mount_info *cmount, const char *path);
+
+/**
+ * Get the id of the named pool.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param pool_name the name of the pool.
+ * @returns the pool id, or a negative error code on failure.
+ */
+int ceph_get_pool_id(struct ceph_mount_info *cmount, const char *pool_name);
+
+/**
+ * Get the pool replication factor.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param pool_id the pool id to look up
+ * @returns the replication factor, or a negative error code on failure.
+ */
+int ceph_get_pool_replication(struct ceph_mount_info *cmount, int pool_id);
+
+/**
+ * Get the OSD address where the primary copy of a file stripe is located.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fd the open file descriptor referring to the file to get the striping unit of.
+ * @param offset the offset into the file to specify the stripe.  The offset can be
+ *	anywhere within the stripe unit.
+ * @param addr the address of the OSD holding that stripe
+ * @param naddr the capacity of the address passed in.
+ * @returns the size of the addressed filled into the @e addr parameter, or a negative
+ *	error code on failure.
+ */
+int ceph_get_file_stripe_address(struct ceph_mount_info *cmount, int fd, int64_t offset,
+				 struct sockaddr_storage *addr, int naddr);
+
+/**
+ * Get the list of OSDs where the objects containing a file offset are located.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fd the open file descriptor referring to the file.
+ * @param offset the offset within the file.
+ * @param length return the number of bytes between the offset and the end of
+ * the stripe unit (optional).
+ * @param osds an integer array to hold the OSD ids.
+ * @param nosds the size of the integer array.
+ * @returns the number of items stored in the output array, or -ERANGE if the
+ * array is not large enough.
+ */
+int ceph_get_file_extent_osds(struct ceph_mount_info *cmount, int fd,
+                              int64_t offset, int64_t *length, int *osds, int nosds);
+
+/**
+ * Get the fully qualified CRUSH location of an OSD.
+ *
+ * Returns (type, name) string pairs for each device in the CRUSH bucket
+ * hierarchy starting from the given osd to the root. Each pair element is
+ * separated by a NULL character.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param osd the OSD id.
+ * @param path buffer to store location.
+ * @param len size of buffer.
+ * @returns the amount of bytes written into the buffer, or -ERANGE if the
+ * array is not large enough.
+ */
+int ceph_get_osd_crush_location(struct ceph_mount_info *cmount,
+    int osd, char *path, size_t len);
+
+/**
+ * Get the network address of an OSD.
+ *
+ * @param cmount the ceph mount handle.
+ * @param osd the OSD id.
+ * @param addr the OSD network address.
+ * @returns zero on success, other returns a negative error code.
+ */
+int ceph_get_osd_addr(struct ceph_mount_info *cmount, int osd,
+    struct sockaddr_storage *addr);
+
+/**
+ * Get the file layout stripe unit granularity.
+ * @param cmount the ceph mount handle.
+ * @returns the stripe unit granularity or a negative error code on failure.
+ */
+int ceph_get_stripe_unit_granularity(struct ceph_mount_info *cmount);
+
+/** @} filelayout */
+
+/**
+ * No longer available.  Do not use.
+ * These functions will return -EOPNOTSUPP.
+ */
+int ceph_set_default_file_stripe_unit(struct ceph_mount_info *cmount, int stripe);
+int ceph_set_default_file_stripe_count(struct ceph_mount_info *cmount, int count);
+int ceph_set_default_object_size(struct ceph_mount_info *cmount, int size);
+int ceph_set_default_preferred_pg(struct ceph_mount_info *cmount, int osd);
+int ceph_set_default_file_replication(struct ceph_mount_info *cmount, int replication);
+
+/**
+ * Read from local replicas when possible.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param val a boolean to set (1) or clear (0) the option to favor local objects
+ *     for reads.
+ * @returns 0
+ */
+int ceph_localize_reads(struct ceph_mount_info *cmount, int val);
+
+/**
+ * Get the osd id of the local osd (if any)
+ *
+ * @param cmount the ceph mount handle to use.
+ * @returns the osd (if any) local to the node where this call is made, otherwise
+ *	-1 is returned.
+ */
+int ceph_get_local_osd(struct ceph_mount_info *cmount);
+
+/** @} default_filelayout */
+
+/**
+ * Get the capabilities currently issued to the client.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param fd the file descriptor to get issued
+ * @returns the current capabilities issued to this client
+ *       for the open file
+ */
+int ceph_debug_get_fd_caps(struct ceph_mount_info *cmount, int fd);
+
+/**
+ * Get the capabilities currently issued to the client.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param path the path to the file
+ * @returns the current capabilities issued to this client
+ *       for the file
+ */
+int ceph_debug_get_file_caps(struct ceph_mount_info *cmount, const char *path);
+
+/* Low Level */
+struct Inode *ceph_ll_get_inode(struct ceph_mount_info *cmount,
+				vinodeno_t vino);
+
+int ceph_ll_lookup_vino(struct ceph_mount_info *cmount, vinodeno_t vino,
+			Inode **inode);
+
+int ceph_ll_lookup_inode(
+    struct ceph_mount_info *cmount,
+    struct inodeno_t ino,
+    Inode **inode);
+
+/**
+ * Get the root inode of FS. Increase counter of references for root Inode. You must call ceph_ll_forget for it!
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param parent pointer to pointer to Inode struct. Pointer to root inode will be returned
+ * @returns 0 if all good
+ */
+int ceph_ll_lookup_root(struct ceph_mount_info *cmount,
+                  Inode **parent);
+int ceph_ll_lookup(struct ceph_mount_info *cmount, Inode *parent,
+		   const char *name, Inode **out, struct ceph_statx *stx,
+		   unsigned want, unsigned flags, const UserPerm *perms);
+int ceph_ll_put(struct ceph_mount_info *cmount, struct Inode *in);
+int ceph_ll_forget(struct ceph_mount_info *cmount, struct Inode *in,
+		   int count);
+int ceph_ll_walk(struct ceph_mount_info *cmount, const char* name, Inode **i,
+		 struct ceph_statx *stx, unsigned int want, unsigned int flags,
+		 const UserPerm *perms);
+int ceph_ll_getattr(struct ceph_mount_info *cmount, struct Inode *in,
+		    struct ceph_statx *stx, unsigned int want, unsigned int flags,
+		    const UserPerm *perms);
+int ceph_ll_setattr(struct ceph_mount_info *cmount, struct Inode *in,
+		    struct ceph_statx *stx, int mask, const UserPerm *perms);
+int ceph_ll_open(struct ceph_mount_info *cmount, struct Inode *in, int flags,
+		 struct Fh **fh, const UserPerm *perms);
+off_t ceph_ll_lseek(struct ceph_mount_info *cmount, struct Fh* filehandle,
+		     off_t offset, int whence);
+int ceph_ll_read(struct ceph_mount_info *cmount, struct Fh* filehandle,
+		 int64_t off, uint64_t len, char* buf);
+int ceph_ll_fsync(struct ceph_mount_info *cmount, struct Fh *fh,
+		  int syncdataonly);
+int ceph_ll_sync_inode(struct ceph_mount_info *cmount, struct Inode *in,
+		  int syncdataonly);
+int ceph_ll_fallocate(struct ceph_mount_info *cmount, struct Fh *fh,
+		      int mode, int64_t offset, int64_t length);
+int ceph_ll_write(struct ceph_mount_info *cmount, struct Fh* filehandle,
+		  int64_t off, uint64_t len, const char *data);
+int64_t ceph_ll_readv(struct ceph_mount_info *cmount, struct Fh *fh,
+		      const struct iovec *iov, int iovcnt, int64_t off);
+int64_t ceph_ll_writev(struct ceph_mount_info *cmount, struct Fh *fh,
+		       const struct iovec *iov, int iovcnt, int64_t off);
+int ceph_ll_close(struct ceph_mount_info *cmount, struct Fh* filehandle);
+int ceph_ll_iclose(struct ceph_mount_info *cmount, struct Inode *in, int mode);
+/**
+ * Get xattr value by xattr name.
+ *
+ * @param cmount the ceph mount handle to use.
+ * @param in file handle
+ * @param name name of attribute
+ * @param value pointer to begin buffer
+ * @param size buffer size
+ * @param perms pointer to UserPerms object
+ * @returns size of returned buffer. Negative number in error case
+ */
+int ceph_ll_getxattr(struct ceph_mount_info *cmount, struct Inode *in,
+		     const char *name, void *value, size_t size,
+		     const UserPerm *perms);
+int ceph_ll_setxattr(struct ceph_mount_info *cmount, struct Inode *in,
+		     const char *name, const void *value, size_t size,
+		     int flags, const UserPerm *perms);
+int ceph_ll_listxattr(struct ceph_mount_info *cmount, struct Inode *in,
+                      char *list, size_t buf_size, size_t *list_size,
+		      const UserPerm *perms);
+int ceph_ll_removexattr(struct ceph_mount_info *cmount, struct Inode *in,
+			const char *name, const UserPerm *perms);
+int ceph_ll_create(struct ceph_mount_info *cmount, Inode *parent,
+		   const char *name, mode_t mode, int oflags, Inode **outp,
+		   Fh **fhp, struct ceph_statx *stx, unsigned want,
+		   unsigned lflags, const UserPerm *perms);
+int ceph_ll_mknod(struct ceph_mount_info *cmount, Inode *parent,
+		  const char *name, mode_t mode, dev_t rdev, Inode **out,
+		  struct ceph_statx *stx, unsigned want, unsigned flags,
+		  const UserPerm *perms);
+int ceph_ll_mkdir(struct ceph_mount_info *cmount, Inode *parent,
+		  const char *name, mode_t mode, Inode **out,
+		  struct ceph_statx *stx, unsigned want,
+		  unsigned flags, const UserPerm *perms);
+int ceph_ll_link(struct ceph_mount_info *cmount, struct Inode *in,
+		 struct Inode *newparent, const char *name,
+		 const UserPerm *perms);
+int ceph_ll_opendir(struct ceph_mount_info *cmount, struct Inode *in,
+		    struct ceph_dir_result **dirpp, const UserPerm *perms);
+int ceph_ll_releasedir(struct ceph_mount_info *cmount,
+		       struct ceph_dir_result* dir);
+int ceph_ll_rename(struct ceph_mount_info *cmount, struct Inode *parent,
+		   const char *name, struct Inode *newparent,
+		   const char *newname, const UserPerm *perms);
+int ceph_ll_unlink(struct ceph_mount_info *cmount, struct Inode *in,
+		   const char *name, const UserPerm *perms);
+int ceph_ll_statfs(struct ceph_mount_info *cmount, struct Inode *in,
+		   struct statvfs *stbuf);
+int ceph_ll_readlink(struct ceph_mount_info *cmount, struct Inode *in,
+		     char *buf, size_t bufsize, const UserPerm *perms);
+int ceph_ll_symlink(struct ceph_mount_info *cmount,
+		    Inode *in, const char *name, const char *value,
+		    Inode **out, struct ceph_statx *stx,
+		    unsigned want, unsigned flags,
+		    const UserPerm *perms);
+int ceph_ll_rmdir(struct ceph_mount_info *cmount, struct Inode *in,
+		  const char *name, const UserPerm *perms);
+uint32_t ceph_ll_stripe_unit(struct ceph_mount_info *cmount,
+			     struct Inode *in);
+uint32_t ceph_ll_file_layout(struct ceph_mount_info *cmount,
+			     struct Inode *in,
+			     struct ceph_file_layout *layout);
+uint64_t ceph_ll_snap_seq(struct ceph_mount_info *cmount,
+			  struct Inode *in);
+int ceph_ll_get_stripe_osd(struct ceph_mount_info *cmount,
+			   struct Inode *in,
+			   uint64_t blockno,
+			   struct ceph_file_layout* layout);
+int ceph_ll_num_osds(struct ceph_mount_info *cmount);
+int ceph_ll_osdaddr(struct ceph_mount_info *cmount,
+		    int osd, uint32_t *addr);
+uint64_t ceph_ll_get_internal_offset(struct ceph_mount_info *cmount,
+				     struct Inode *in, uint64_t blockno);
+int ceph_ll_read_block(struct ceph_mount_info *cmount,
+		       struct Inode *in, uint64_t blockid,
+		       char* bl, uint64_t offset, uint64_t length,
+		       struct ceph_file_layout* layout);
+int ceph_ll_write_block(struct ceph_mount_info *cmount,
+			struct Inode *in, uint64_t blockid,
+			char* buf, uint64_t offset,
+			uint64_t length, struct ceph_file_layout* layout,
+			uint64_t snapseq, uint32_t sync);
+int ceph_ll_commit_blocks(struct ceph_mount_info *cmount,
+			  struct Inode *in, uint64_t offset, uint64_t range);
+
+
+int ceph_ll_getlk(struct ceph_mount_info *cmount,
+		  Fh *fh, struct flock *fl, uint64_t owner);
+int ceph_ll_setlk(struct ceph_mount_info *cmount,
+		  Fh *fh, struct flock *fl, uint64_t owner, int sleep);
+
+int ceph_ll_lazyio(struct ceph_mount_info *cmount, Fh *fh, int enable);
+
+/*
+ * Delegation support
+ *
+ * Delegations are way for an application to request exclusive or
+ * semi-exclusive access to an Inode. The client requests the delegation and
+ * if it's successful it can reliably cache file data and metadata until the
+ * delegation is recalled.
+ *
+ * Recalls are issued via a callback function, provided by the application.
+ * Callback functions should act something like signal handlers.  You want to
+ * do as little as possible in the callback. Any major work should be deferred
+ * in some fashion as it's difficult to predict the context in which this
+ * function will be called.
+ *
+ * Once the delegation has been recalled, the application should return it as
+ * soon as possible. The application has client_deleg_timeout seconds to
+ * return it, after which the cmount structure is forcibly unmounted and
+ * further calls into it fail.
+ *
+ * The application can set the client_deleg_timeout config option to suit its
+ * needs, but it should take care to choose a value that allows it to avoid
+ * forcible eviction from the cluster in the event of an application bug.
+ */
+
+/* Commands for manipulating delegation state */
+#ifndef CEPH_DELEGATION_NONE
+# define CEPH_DELEGATION_NONE	0
+# define CEPH_DELEGATION_RD	1
+# define CEPH_DELEGATION_WR	2
+#endif
+
+/**
+ * Get the amount of time that the client has to return caps
+ * @param cmount the ceph mount handle to use.
+ *
+ * In the event that a client does not return its caps, the MDS may blocklist
+ * it after this timeout. Applications should check this value and ensure
+ * that they set the delegation timeout to a value lower than this.
+ *
+ * This call returns the cap return timeout (in seconds) for this cmount, or
+ * zero if it's not mounted.
+ */
+uint32_t ceph_get_cap_return_timeout(struct ceph_mount_info *cmount);
+
+/**
+ * Set the delegation timeout for the mount (thereby enabling delegations)
+ * @param cmount the ceph mount handle to use.
+ * @param timeout the delegation timeout (in seconds)
+ *
+ * Since the client could end up blocklisted if it doesn't return delegations
+ * in time, we mandate that any application wanting to use delegations
+ * explicitly set the timeout beforehand. Until this call is done on the
+ * mount, attempts to set a delegation will return -ETIME.
+ *
+ * Once a delegation is recalled, if it is not returned in this amount of
+ * time, the cmount will be forcibly unmounted and further access attempts
+ * will fail (usually with -ENOTCONN errors).
+ *
+ * This value is further vetted against the cap return timeout, and this call
+ * can fail with -EINVAL if the timeout value is too long. Delegations can be
+ * disabled again by setting the timeout to 0.
+ */
+int ceph_set_deleg_timeout(struct ceph_mount_info *cmount, uint32_t timeout);
+
+/**
+ * Request a delegation on an open Fh
+ * @param cmount the ceph mount handle to use.
+ * @param fh file handle
+ * @param cmd CEPH_DELEGATION_* command
+ * @param cb callback function for recalling delegation
+ * @param priv opaque token passed back during recalls
+ *
+ * Returns 0 if the delegation was granted, -EAGAIN if there was a conflict
+ * and other error codes if there is a fatal error of some sort (e.g. -ENOMEM,
+ * -ETIME)
+ */
+int ceph_ll_delegation(struct ceph_mount_info *cmount, Fh *fh,
+		       unsigned int cmd, ceph_deleg_cb_t cb, void *priv);
+
+mode_t ceph_umask(struct ceph_mount_info *cmount, mode_t mode);
+
+/* state reclaim */
+#define CEPH_RECLAIM_RESET 	1
+
+/**
+ * Set ceph client uuid
+ * @param cmount the ceph mount handle to use.
+ * @param uuid the uuid to set
+ *
+ * Must be called before mount.
+ */
+void ceph_set_uuid(struct ceph_mount_info *cmount, const char *uuid);
+
+/**
+ * Set ceph client session timeout
+ * @param cmount the ceph mount handle to use.
+ * @param timeout the timeout to set
+ *
+ * Must be called before mount.
+ */
+void ceph_set_session_timeout(struct ceph_mount_info *cmount, unsigned timeout);
+
+/**
+ * Start to reclaim states of other client
+ * @param cmount the ceph mount handle to use.
+ * @param uuid uuid of client whose states need to be reclaimed
+ * @param flags flags that control how states get reclaimed
+ *
+ * Returns 0 success, -EOPNOTSUPP if mds does not support the operation,
+ * -ENOENT if CEPH_RECLAIM_RESET is specified and there is no client
+ * with the given uuid, -ENOTRECOVERABLE in all other error cases.
+ */
+int ceph_start_reclaim(struct ceph_mount_info *cmount,
+		       const char *uuid, unsigned flags);
+
+/**
+ * finish reclaiming states of other client (
+ * @param cmount the ceph mount handle to use.
+ */
+void ceph_finish_reclaim(struct ceph_mount_info *cmount);
+
+/**
+ * Register a set of callbacks to be used with this cmount
+ *
+ * This is deprecated, use ceph_ll_register_callbacks2() instead.
+ *
+ * @param cmount the ceph mount handle on which the cb's should be registerd
+ * @param args   callback arguments to register with the cmount
+ *
+ * Any fields set to NULL will be ignored. There currently is no way to
+ * unregister these callbacks, so this is a one-way change.
+ */
+void ceph_ll_register_callbacks(struct ceph_mount_info *cmount,
+				struct ceph_client_callback_args *args);
+
+/**
+ * Register a set of callbacks to be used with this cmount
+ * @param cmount the ceph mount handle on which the cb's should be registerd
+ * @param args   callback arguments to register with the cmount
+ *
+ * Any fields set to NULL will be ignored. There currently is no way to
+ * unregister these callbacks, so this is a one-way change.
+ *
+ * Returns 0 on success or -EBUSY if the cmount is mounting or already mounted.
+ */
+int ceph_ll_register_callbacks2(struct ceph_mount_info *cmount,
+				struct ceph_client_callback_args *args);
+
+/**
+ * Get snapshot info
+ *
+ * @param cmount the ceph mount handle to use for making the directory.
+ * @param path the path of the snapshot.  This must be either an
+ *        absolute path or a relative path off of the current working directory.
+ * @returns 0 on success or a negative return code on error.
+ */
+int ceph_get_snap_info(struct ceph_mount_info *cmount,
+                       const char *path, struct snap_info *snap_info);
+
+/**
+ * Free snapshot info buffers
+ *
+ * @param snap_info snapshot info struct (fetched via call to ceph_get_snap_info()).
+ */
+void ceph_free_snap_info_buffer(struct snap_info *snap_info);
+#ifdef __cplusplus
+}
+#endif
+
+#endif