[deliverable/linux.git] / fs / ceph / mds_client.h

#ifndef _FS_CEPH_MDS_CLIENT_H
#define _FS_CEPH_MDS_CLIENT_H

#include <linux/completion.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/spinlock.h>

#include <linux/ceph/types.h>
#include <linux/ceph/messenger.h>
#include <linux/ceph/mdsmap.h>
#include <linux/ceph/auth.h>

/*
 * Some lock dependencies:
 *
 * session->s_mutex
 *         mdsc->mutex
 *
 *         mdsc->snap_rwsem
 *
 *         ci->i_ceph_lock
 *                 mdsc->snap_flush_lock
 *                 mdsc->cap_delay_lock
 *
 */

struct ceph_fs_client;
struct ceph_cap;

/*
 * parsed info about a single inode.  pointers are into the encoded
 * on-wire structures within the mds reply message payload.
 */
struct ceph_mds_reply_info_in {
	struct ceph_mds_reply_inode *in;
	struct ceph_dir_layout dir_layout;
	u32 symlink_len;
	char *symlink;
	u32 xattr_len;
	char *xattr_data;
};

/*
 * parsed info about an mds reply, including information about
 * either: 1) the target inode and/or its parent directory and dentry,
 * and directory contents (for readdir results), or
 * 2) the file range lock info (for fcntl F_GETLK results).
 */
struct ceph_mds_reply_info_parsed {
	struct ceph_mds_reply_head    *head;

	/* trace */
	struct ceph_mds_reply_info_in diri, targeti;
	struct ceph_mds_reply_dirfrag *dirfrag;
	char                          *dname;
	u32                           dname_len;
	struct ceph_mds_reply_lease   *dlease;

	/* extra */
	union {
		/* for fcntl F_GETLK results */
		struct ceph_filelock *filelock_reply;

		/* for readdir results */
		struct {
			struct ceph_mds_reply_dirfrag *dir_dir;
			size_t			      dir_buf_size;
			int                           dir_nr;
			char                          **dir_dname;
			u32                           *dir_dname_len;
			struct ceph_mds_reply_lease   **dir_dlease;
			struct ceph_mds_reply_info_in *dir_in;
			u8                            dir_complete, dir_end;
		};

		/* for create results */
		struct {
			bool has_create_ino;
			u64 ino;
		};
	};

	/* encoded blob describing snapshot contexts for certain
	   operations (e.g., open) */
	void *snapblob;
	int snapblob_len;
};


/*
 * cap releases are batched and sent to the MDS en masse.
 */
#define CEPH_CAPS_PER_RELEASE ((PAGE_CACHE_SIZE -			\
				sizeof(struct ceph_mds_cap_release)) /	\
			       sizeof(struct ceph_mds_cap_item))


/*
 * state associated with each MDS<->client session
 */
enum {
	CEPH_MDS_SESSION_NEW = 1,
	CEPH_MDS_SESSION_OPENING = 2,
	CEPH_MDS_SESSION_OPEN = 3,
	CEPH_MDS_SESSION_HUNG = 4,
	CEPH_MDS_SESSION_CLOSING = 5,
	CEPH_MDS_SESSION_RESTARTING = 6,
	CEPH_MDS_SESSION_RECONNECTING = 7,
};

struct ceph_mds_session {
	struct ceph_mds_client *s_mdsc;
	int               s_mds;
	int               s_state;
	unsigned long     s_ttl;      /* time until mds kills us */
	u64               s_seq;      /* incoming msg seq # */
	struct mutex      s_mutex;    /* serialize session messages */

	struct ceph_connection s_con;

	struct ceph_auth_handshake s_auth;

	/* protected by s_gen_ttl_lock */
	spinlock_t        s_gen_ttl_lock;
	u32               s_cap_gen;  /* inc each time we get mds stale msg */
	unsigned long     s_cap_ttl;  /* when session caps expire */

	/* protected by s_cap_lock */
	spinlock_t        s_cap_lock;
	struct list_head  s_caps;     /* all caps issued by this session */
	int               s_nr_caps, s_trim_caps;
	int               s_num_cap_releases;
	int		  s_cap_reconnect;
	struct list_head  s_cap_releases; /* waiting cap_release messages */
	struct list_head  s_cap_releases_done; /* ready to send */
	struct ceph_cap  *s_cap_iterator;

	/* protected by mutex */
	struct list_head  s_cap_flushing;     /* inodes w/ flushing caps */
	struct list_head  s_cap_snaps_flushing;
	unsigned long     s_renew_requested; /* last time we sent a renew req */
	u64               s_renew_seq;

	atomic_t          s_ref;
	struct list_head  s_waiting;  /* waiting requests */
	struct list_head  s_unsafe;   /* unsafe requests */
};

/*
 * modes of choosing which MDS to send a request to
 */
enum {
	USE_ANY_MDS,
	USE_RANDOM_MDS,
	USE_AUTH_MDS,   /* prefer authoritative mds for this metadata item */
};

struct ceph_mds_request;
struct ceph_mds_client;

/*
 * request completion callback
 */
typedef void (*ceph_mds_request_callback_t) (struct ceph_mds_client *mdsc,
					     struct ceph_mds_request *req);

/*
 * an in-flight mds request
 */
struct ceph_mds_request {
	u64 r_tid;                   /* transaction id */
	struct rb_node r_node;
	struct ceph_mds_client *r_mdsc;

	int r_op;                    /* mds op code */

	/* operation on what? */
	struct inode *r_inode;              /* arg1 */
	struct dentry *r_dentry;            /* arg1 */
	struct dentry *r_old_dentry;        /* arg2: rename from or link from */
	struct inode *r_old_dentry_dir;     /* arg2: old dentry's parent dir */
	char *r_path1, *r_path2;
	struct ceph_vino r_ino1, r_ino2;

	struct inode *r_locked_dir; /* dir (if any) i_mutex locked by vfs */
	struct inode *r_target_inode;       /* resulting inode */

	struct mutex r_fill_mutex;

	union ceph_mds_request_args r_args;
	int r_fmode;        /* file mode, if expecting cap */
	kuid_t r_uid;
	kgid_t r_gid;

	/* for choosing which mds to send this request to */
	int r_direct_mode;
	u32 r_direct_hash;      /* choose dir frag based on this dentry hash */
	bool r_direct_is_hash;  /* true if r_direct_hash is valid */

	/* data payload is used for xattr ops */
	struct page **r_pages;
	int r_num_pages;
	int r_data_len;

	/* what caps shall we drop? */
	int r_inode_drop, r_inode_unless;
	int r_dentry_drop, r_dentry_unless;
	int r_old_dentry_drop, r_old_dentry_unless;
	struct inode *r_old_inode;
	int r_old_inode_drop, r_old_inode_unless;

	struct ceph_msg  *r_request;  /* original request */
	int r_request_release_offset;
	struct ceph_msg  *r_reply;
	struct ceph_mds_reply_info_parsed r_reply_info;
	int r_err;
	bool r_aborted;

	unsigned long r_timeout;  /* optional.  jiffies */
	unsigned long r_started;  /* start time to measure timeout against */
	unsigned long r_request_started; /* start time for mds request only,
					    used to measure lease durations */

	/* link unsafe requests to parent directory, for fsync */
	struct inode	*r_unsafe_dir;
	struct list_head r_unsafe_dir_item;

	struct ceph_mds_session *r_session;

	int               r_attempts;   /* resend attempts */
	int               r_num_fwd;    /* number of forward attempts */
	int               r_resend_mds; /* mds to resend to next, if any*/
	u32               r_sent_on_mseq; /* cap mseq request was sent at*/

	struct kref       r_kref;
	struct list_head  r_wait;
	struct completion r_completion;
	struct completion r_safe_completion;
	ceph_mds_request_callback_t r_callback;
	struct list_head  r_unsafe_item;  /* per-session unsafe list item */
	bool		  r_got_unsafe, r_got_safe, r_got_result;

	bool              r_did_prepopulate;
	u32               r_readdir_offset;

	struct ceph_cap_reservation r_caps_reservation;
	int r_num_caps;
};

/*
 * mds client state
 */
struct ceph_mds_client {
	struct ceph_fs_client  *fsc;
	struct mutex            mutex;         /* all nested structures */

	struct ceph_mdsmap      *mdsmap;
	struct completion       safe_umount_waiters;
	wait_queue_head_t       session_close_wq;
	struct list_head        waiting_for_map;

	struct ceph_mds_session **sessions;    /* NULL for mds if no session */
	int                     max_sessions;  /* len of s_mds_sessions */
	int                     stopping;      /* true if shutting down */

	/*
	 * snap_rwsem will cover cap linkage into snaprealms, and
	 * realm snap contexts.  (later, we can do per-realm snap
	 * contexts locks..)  the empty list contains realms with no
	 * references (implying they contain no inodes with caps) that
	 * should be destroyed.
	 */
	struct rw_semaphore     snap_rwsem;
	struct rb_root          snap_realms;
	struct list_head        snap_empty;
	spinlock_t              snap_empty_lock;  /* protect snap_empty */

	u64                    last_tid;      /* most recent mds request */
	struct rb_root         request_tree;  /* pending mds requests */
	struct delayed_work    delayed_work;  /* delayed work */
	unsigned long    last_renew_caps;  /* last time we renewed our caps */
	struct list_head cap_delay_list;   /* caps with delayed release */
	spinlock_t       cap_delay_lock;   /* protects cap_delay_list */
	struct list_head snap_flush_list;  /* cap_snaps ready to flush */
	spinlock_t       snap_flush_lock;

	u64               cap_flush_seq;
	struct list_head  cap_dirty;        /* inodes with dirty caps */
	struct list_head  cap_dirty_migrating; /* ...that are migration... */
	int               num_cap_flushing; /* # caps we are flushing */
	spinlock_t        cap_dirty_lock;   /* protects above items */
	wait_queue_head_t cap_flushing_wq;

	/*
	 * Cap reservations
	 *
	 * Maintain a global pool of preallocated struct ceph_caps, referenced
	 * by struct ceph_caps_reservations.  This ensures that we preallocate
	 * memory needed to successfully process an MDS response.  (If an MDS
	 * sends us cap information and we fail to process it, we will have
	 * problems due to the client and MDS being out of sync.)
	 *
	 * Reservations are 'owned' by a ceph_cap_reservation context.
	 */
	spinlock_t	caps_list_lock;
	struct		list_head caps_list; /* unused (reserved or
						unreserved) */
	int		caps_total_count;    /* total caps allocated */
	int		caps_use_count;      /* in use */
	int		caps_reserve_count;  /* unused, reserved */
	int		caps_avail_count;    /* unused, unreserved */
	int		caps_min_count;      /* keep at least this many
						(unreserved) */
	spinlock_t	  dentry_lru_lock;
	struct list_head  dentry_lru;
	int		  num_dentry;
};

extern const char *ceph_mds_op_name(int op);

extern struct ceph_mds_session *
__ceph_lookup_mds_session(struct ceph_mds_client *, int mds);

static inline struct ceph_mds_session *
ceph_get_mds_session(struct ceph_mds_session *s)
{
	atomic_inc(&s->s_ref);
	return s;
}

extern void ceph_put_mds_session(struct ceph_mds_session *s);

extern int ceph_send_msg_mds(struct ceph_mds_client *mdsc,
			     struct ceph_msg *msg, int mds);

extern int ceph_mdsc_init(struct ceph_fs_client *fsc);
extern void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc);
extern void ceph_mdsc_destroy(struct ceph_fs_client *fsc);

extern void ceph_mdsc_sync(struct ceph_mds_client *mdsc);

extern void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc,
				    struct inode *inode,
				    struct dentry *dn);

extern void ceph_invalidate_dir_request(struct ceph_mds_request *req);
extern int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
					   struct inode *dir);
extern struct ceph_mds_request *
ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode);
extern void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
				     struct ceph_mds_request *req);
extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
				struct inode *dir,
				struct ceph_mds_request *req);
static inline void ceph_mdsc_get_request(struct ceph_mds_request *req)
{
	kref_get(&req->r_kref);
}
extern void ceph_mdsc_release_request(struct kref *kref);
static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
{
	kref_put(&req->r_kref, ceph_mdsc_release_request);
}

extern int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
				 struct ceph_mds_session *session);
extern void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
				   struct ceph_mds_session *session);

extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);

extern char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
				  int stop_on_nosnap);

extern void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry);
extern void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
				     struct inode *inode,
				     struct dentry *dentry, char action,
				     u32 seq);

extern void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc,
				 struct ceph_msg *msg);

extern struct ceph_mds_session *
ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target);
extern void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
					  struct ceph_mds_session *session);

#endif
Commit	Line	Data
2f2dc053 SW	1	#ifndef _FS_CEPH_MDS_CLIENT_H
	2	#define _FS_CEPH_MDS_CLIENT_H
	3
	4	#include <linux/completion.h>
153c8e6b	5	#include <linux/kref.h>
2f2dc053 SW	6	#include <linux/list.h>
2f2dc053 SW	7	#include <linux/mutex.h>
44ca18f2	8	#include <linux/rbtree.h>
2f2dc053 SW	9	#include <linux/spinlock.h>
2f2dc053 SW	10
3d14c5d2 YS	11	#include <linux/ceph/types.h>
	12	#include <linux/ceph/messenger.h>
	13	#include <linux/ceph/mdsmap.h>
6c4a1915	14	#include <linux/ceph/auth.h>
2f2dc053 SW	15
	16	/*
	17	* Some lock dependencies:
	18	*
	19	* session->s_mutex
	20	* mdsc->mutex
	21	*
	22	* mdsc->snap_rwsem
	23	*
be655596	24	* ci->i_ceph_lock
2f2dc053 SW	25	* mdsc->snap_flush_lock
	26	* mdsc->cap_delay_lock
	27	*
	28	*/
	29
3d14c5d2	30	struct ceph_fs_client;
2f2dc053 SW	31	struct ceph_cap;
	32
	33	/*
	34	* parsed info about a single inode. pointers are into the encoded
	35	* on-wire structures within the mds reply message payload.
	36	*/
	37	struct ceph_mds_reply_info_in {
	38	struct ceph_mds_reply_inode *in;
14303d20	39	struct ceph_dir_layout dir_layout;
2f2dc053 SW	40	u32 symlink_len;
	41	char *symlink;
	42	u32 xattr_len;
	43	char *xattr_data;
	44	};
	45
	46	/*
25933abd HS	47	* parsed info about an mds reply, including information about
	48	* either: 1) the target inode and/or its parent directory and dentry,
	49	* and directory contents (for readdir results), or
	50	* 2) the file range lock info (for fcntl F_GETLK results).
2f2dc053 SW	51	*/
	52	struct ceph_mds_reply_info_parsed {
	53	struct ceph_mds_reply_head *head;
	54
25933abd	55	/* trace */
2f2dc053 SW	56	struct ceph_mds_reply_info_in diri, targeti;
	57	struct ceph_mds_reply_dirfrag *dirfrag;
	58	char *dname;
	59	u32 dname_len;
	60	struct ceph_mds_reply_lease *dlease;
	61
25933abd HS	62	/* extra */
	63	union {
	64	/* for fcntl F_GETLK results */
	65	struct ceph_filelock *filelock_reply;
	66
	67	/* for readdir results */
	68	struct {
	69	struct ceph_mds_reply_dirfrag *dir_dir;
54008399	70	size_t dir_buf_size;
25933abd HS	71	int dir_nr;
	72	char **dir_dname;
	73	u32 *dir_dname_len;
	74	struct ceph_mds_reply_lease **dir_dlease;
	75	struct ceph_mds_reply_info_in *dir_in;
	76	u8 dir_complete, dir_end;
	77	};
6e8575fa SL	78
	79	/* for create results */
	80	struct {
	81	bool has_create_ino;
	82	u64 ino;
	83	};
25933abd	84	};
2f2dc053 SW	85
	86	/* encoded blob describing snapshot contexts for certain
	87	operations (e.g., open) */
	88	void *snapblob;
	89	int snapblob_len;
	90	};
	91
	92
	93	/*
	94	* cap releases are batched and sent to the MDS en masse.
	95	*/
	96	#define CEPH_CAPS_PER_RELEASE ((PAGE_CACHE_SIZE - \
	97	sizeof(struct ceph_mds_cap_release)) / \
	98	sizeof(struct ceph_mds_cap_item))
	99
	100
	101	/*
	102	* state associated with each MDS<->client session
	103	*/
	104	enum {
	105	CEPH_MDS_SESSION_NEW = 1,
	106	CEPH_MDS_SESSION_OPENING = 2,
	107	CEPH_MDS_SESSION_OPEN = 3,
	108	CEPH_MDS_SESSION_HUNG = 4,
	109	CEPH_MDS_SESSION_CLOSING = 5,
	110	CEPH_MDS_SESSION_RESTARTING = 6,
	111	CEPH_MDS_SESSION_RECONNECTING = 7,
	112	};
	113
	114	struct ceph_mds_session {
	115	struct ceph_mds_client *s_mdsc;
	116	int s_mds;
	117	int s_state;
	118	unsigned long s_ttl; /* time until mds kills us */
	119	u64 s_seq; /* incoming msg seq # */
	120	struct mutex s_mutex; /* serialize session messages */
	121
	122	struct ceph_connection s_con;
	123
6c4a1915	124	struct ceph_auth_handshake s_auth;
4e7a5dcd	125
d8fb02ab AE	126	/* protected by s_gen_ttl_lock */
d8fb02ab AE	127	spinlock_t s_gen_ttl_lock;
2f2dc053 SW	128	u32 s_cap_gen; /* inc each time we get mds stale msg */
2f2dc053 SW	129	unsigned long s_cap_ttl; /* when session caps expire */
d8fb02ab AE	130
	131	/* protected by s_cap_lock */
	132	spinlock_t s_cap_lock;
2f2dc053 SW	133	struct list_head s_caps; /* all caps issued by this session */
	134	int s_nr_caps, s_trim_caps;
	135	int s_num_cap_releases;
99a9c273	136	int s_cap_reconnect;
2f2dc053 SW	137	struct list_head s_cap_releases; /* waiting cap_release messages */
2f2dc053 SW	138	struct list_head s_cap_releases_done; /* ready to send */
7c1332b8	139	struct ceph_cap *s_cap_iterator;
2f2dc053 SW	140
	141	/* protected by mutex */
	142	struct list_head s_cap_flushing; /* inodes w/ flushing caps */
	143	struct list_head s_cap_snaps_flushing;
	144	unsigned long s_renew_requested; /* last time we sent a renew req */
	145	u64 s_renew_seq;
	146
	147	atomic_t s_ref;
	148	struct list_head s_waiting; /* waiting requests */
	149	struct list_head s_unsafe; /* unsafe requests */
	150	};
	151
	152	/*
	153	* modes of choosing which MDS to send a request to
	154	*/
	155	enum {
	156	USE_ANY_MDS,
	157	USE_RANDOM_MDS,
	158	USE_AUTH_MDS, /* prefer authoritative mds for this metadata item */
	159	};
	160
	161	struct ceph_mds_request;
	162	struct ceph_mds_client;
	163
	164	/*
	165	* request completion callback
	166	*/
	167	typedef void (ceph_mds_request_callback_t) (struct ceph_mds_client mdsc,
	168	struct ceph_mds_request *req);
	169
	170	/*
	171	* an in-flight mds request
	172	*/
	173	struct ceph_mds_request {
	174	u64 r_tid; /* transaction id */
44ca18f2	175	struct rb_node r_node;
37151668	176	struct ceph_mds_client *r_mdsc;
2f2dc053 SW	177
2f2dc053 SW	178	int r_op; /* mds op code */
2f2dc053 SW	179
	180	/* operation on what? */
	181	struct inode r_inode; / arg1 */
	182	struct dentry r_dentry; / arg1 */
	183	struct dentry r_old_dentry; / arg2: rename from or link from */
41b02e1f	184	struct inode r_old_dentry_dir; / arg2: old dentry's parent dir */
2f2dc053 SW	185	char r_path1, r_path2;
	186	struct ceph_vino r_ino1, r_ino2;
	187
	188	struct inode r_locked_dir; / dir (if any) i_mutex locked by vfs */
	189	struct inode r_target_inode; / resulting inode */
	190
b4556396 SW	191	struct mutex r_fill_mutex;
b4556396 SW	192
2f2dc053 SW	193	union ceph_mds_request_args r_args;
2f2dc053 SW	194	int r_fmode; /* file mode, if expecting cap */
ff3d0046 EB	195	kuid_t r_uid;
ff3d0046 EB	196	kgid_t r_gid;
2f2dc053 SW	197
	198	/* for choosing which mds to send this request to */
	199	int r_direct_mode;
	200	u32 r_direct_hash; /* choose dir frag based on this dentry hash */
	201	bool r_direct_is_hash; /* true if r_direct_hash is valid */
	202
	203	/* data payload is used for xattr ops */
	204	struct page **r_pages;
	205	int r_num_pages;
	206	int r_data_len;
	207
	208	/* what caps shall we drop? */
	209	int r_inode_drop, r_inode_unless;
	210	int r_dentry_drop, r_dentry_unless;
	211	int r_old_dentry_drop, r_old_dentry_unless;
	212	struct inode *r_old_inode;
	213	int r_old_inode_drop, r_old_inode_unless;
	214
	215	struct ceph_msg r_request; / original request */
e979cf50	216	int r_request_release_offset;
2f2dc053 SW	217	struct ceph_msg *r_reply;
	218	struct ceph_mds_reply_info_parsed r_reply_info;
	219	int r_err;
5b1daecd	220	bool r_aborted;
2f2dc053 SW	221
	222	unsigned long r_timeout; /* optional. jiffies */
	223	unsigned long r_started; /* start time to measure timeout against */
	224	unsigned long r_request_started; /* start time for mds request only,
	225	used to measure lease durations */
	226
	227	/* link unsafe requests to parent directory, for fsync */
	228	struct inode *r_unsafe_dir;
	229	struct list_head r_unsafe_dir_item;
	230
	231	struct ceph_mds_session *r_session;
	232
	233	int r_attempts; /* resend attempts */
	234	int r_num_fwd; /* number of forward attempts */
2f2dc053	235	int r_resend_mds; /* mds to resend to next, if any*/
e55b71f8	236	u32 r_sent_on_mseq; /* cap mseq request was sent at*/
2f2dc053	237
153c8e6b	238	struct kref r_kref;
2f2dc053 SW	239	struct list_head r_wait;
	240	struct completion r_completion;
	241	struct completion r_safe_completion;
	242	ceph_mds_request_callback_t r_callback;
	243	struct list_head r_unsafe_item; /* per-session unsafe list item */
e1518c7c	244	bool r_got_unsafe, r_got_safe, r_got_result;
2f2dc053 SW	245
	246	bool r_did_prepopulate;
	247	u32 r_readdir_offset;
	248
	249	struct ceph_cap_reservation r_caps_reservation;
	250	int r_num_caps;
	251	};
	252
	253	/*
	254	* mds client state
	255	*/
	256	struct ceph_mds_client {
3d14c5d2	257	struct ceph_fs_client *fsc;
2f2dc053 SW	258	struct mutex mutex; /* all nested structures */
	259
	260	struct ceph_mdsmap *mdsmap;
f3c60c59 SW	261	struct completion safe_umount_waiters;
f3c60c59 SW	262	wait_queue_head_t session_close_wq;
2f2dc053 SW	263	struct list_head waiting_for_map;
	264
	265	struct ceph_mds_session *sessions; / NULL for mds if no session */
	266	int max_sessions; /* len of s_mds_sessions */
	267	int stopping; /* true if shutting down */
	268
	269	/*
	270	* snap_rwsem will cover cap linkage into snaprealms, and
	271	* realm snap contexts. (later, we can do per-realm snap
	272	* contexts locks..) the empty list contains realms with no
	273	* references (implying they contain no inodes with caps) that
	274	* should be destroyed.
	275	*/
	276	struct rw_semaphore snap_rwsem;
a105f00c	277	struct rb_root snap_realms;
2f2dc053 SW	278	struct list_head snap_empty;
	279	spinlock_t snap_empty_lock; /* protect snap_empty */
	280
	281	u64 last_tid; /* most recent mds request */
44ca18f2	282	struct rb_root request_tree; /* pending mds requests */
2f2dc053 SW	283	struct delayed_work delayed_work; /* delayed work */
	284	unsigned long last_renew_caps; /* last time we renewed our caps */
	285	struct list_head cap_delay_list; /* caps with delayed release */
	286	spinlock_t cap_delay_lock; /* protects cap_delay_list */
	287	struct list_head snap_flush_list; /* cap_snaps ready to flush */
	288	spinlock_t snap_flush_lock;
	289
	290	u64 cap_flush_seq;
	291	struct list_head cap_dirty; /* inodes with dirty caps */
db354052	292	struct list_head cap_dirty_migrating; /* ...that are migration... */
2f2dc053 SW	293	int num_cap_flushing; /* # caps we are flushing */
	294	spinlock_t cap_dirty_lock; /* protects above items */
	295	wait_queue_head_t cap_flushing_wq;
	296
37151668 YS	297	/*
	298	* Cap reservations
	299	*
	300	* Maintain a global pool of preallocated struct ceph_caps, referenced
	301	* by struct ceph_caps_reservations. This ensures that we preallocate
	302	* memory needed to successfully process an MDS response. (If an MDS
	303	* sends us cap information and we fail to process it, we will have
	304	* problems due to the client and MDS being out of sync.)
	305	*
	306	* Reservations are 'owned' by a ceph_cap_reservation context.
	307	*/
	308	spinlock_t caps_list_lock;
	309	struct list_head caps_list; /* unused (reserved or
	310	unreserved) */
	311	int caps_total_count; /* total caps allocated */
	312	int caps_use_count; /* in use */
	313	int caps_reserve_count; /* unused, reserved */
	314	int caps_avail_count; /* unused, unreserved */
	315	int caps_min_count; /* keep at least this many
	316	(unreserved) */
2f2dc053 SW	317	spinlock_t dentry_lru_lock;
	318	struct list_head dentry_lru;
	319	int num_dentry;
	320	};
	321
	322	extern const char *ceph_mds_op_name(int op);
	323
	324	extern struct ceph_mds_session *
	325	__ceph_lookup_mds_session(struct ceph_mds_client *, int mds);
	326
	327	static inline struct ceph_mds_session *
	328	ceph_get_mds_session(struct ceph_mds_session *s)
	329	{
	330	atomic_inc(&s->s_ref);
	331	return s;
	332	}
	333
	334	extern void ceph_put_mds_session(struct ceph_mds_session *s);
	335
	336	extern int ceph_send_msg_mds(struct ceph_mds_client *mdsc,
	337	struct ceph_msg *msg, int mds);
	338
3d14c5d2	339	extern int ceph_mdsc_init(struct ceph_fs_client *fsc);
2f2dc053	340	extern void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc);
3d14c5d2	341	extern void ceph_mdsc_destroy(struct ceph_fs_client *fsc);
2f2dc053 SW	342
	343	extern void ceph_mdsc_sync(struct ceph_mds_client *mdsc);
	344
	345	extern void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc,
	346	struct inode *inode,
2f90b852	347	struct dentry *dn);
2f2dc053	348
167c9e35	349	extern void ceph_invalidate_dir_request(struct ceph_mds_request *req);
54008399 YZ	350	extern int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
54008399 YZ	351	struct inode *dir);
2f2dc053 SW	352	extern struct ceph_mds_request *
	353	ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode);
	354	extern void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
	355	struct ceph_mds_request *req);
	356	extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
	357	struct inode *dir,
	358	struct ceph_mds_request *req);
	359	static inline void ceph_mdsc_get_request(struct ceph_mds_request *req)
	360	{
153c8e6b SW	361	kref_get(&req->r_kref);
	362	}
	363	extern void ceph_mdsc_release_request(struct kref *kref);
	364	static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
	365	{
	366	kref_put(&req->r_kref, ceph_mdsc_release_request);
2f2dc053	367	}
2f2dc053	368
2b2300d6	369	extern int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
ee6b272b	370	struct ceph_mds_session *session);
3d7ded4d SW	371	extern void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
	372	struct ceph_mds_session *session);
	373
2f2dc053 SW	374	extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);
	375
	376	extern char ceph_mdsc_build_path(struct dentry dentry, int plen, u64 base,
	377	int stop_on_nosnap);
	378
	379	extern void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry);
	380	extern void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
	381	struct inode *inode,
	382	struct dentry *dentry, char action,
	383	u32 seq);
	384
	385	extern void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc,
	386	struct ceph_msg *msg);
	387
5d72d13c YZ	388	extern struct ceph_mds_session *
5d72d13c YZ	389	ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target);
154f42c2 SW	390	extern void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
	391	struct ceph_mds_session *session);
	392
2f2dc053	393	#endif