Initial import

1 files changed, 608 insertions, 0 deletions

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
new file mode 100644
index 000000000..51cc1deb7
--- /dev/null
+++ b/include/linux/device-mapper.h
@@ -0,0 +1,608 @@
+/*
+ * Copyright (C) 2001 Sistina Software (UK) Limited.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the LGPL.
+ */
+
+#ifndef _LINUX_DEVICE_MAPPER_H
+#define _LINUX_DEVICE_MAPPER_H
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/math64.h>
+#include <linux/ratelimit.h>
+
+struct dm_dev;
+struct dm_target;
+struct dm_table;
+struct mapped_device;
+struct bio_vec;
+
+typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
+
+union map_info {
+	void *ptr;
+};
+
+/*
+ * In the constructor the target parameter will already have the
+ * table, type, begin and len fields filled in.
+ */
+typedef int (*dm_ctr_fn) (struct dm_target *target,
+			  unsigned int argc, char **argv);
+
+/*
+ * The destructor doesn't need to free the dm_target, just
+ * anything hidden ti->private.
+ */
+typedef void (*dm_dtr_fn) (struct dm_target *ti);
+
+/*
+ * The map function must return:
+ * < 0: error
+ * = 0: The target will handle the io by resubmitting it later
+ * = 1: simple remap complete
+ * = 2: The target wants to push back the io
+ */
+typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
+typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
+				  union map_info *map_context);
+typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
+					    struct request *rq,
+					    union map_info *map_context,
+					    struct request **clone);
+typedef void (*dm_release_clone_request_fn) (struct request *clone);
+
+/*
+ * Returns:
+ * < 0 : error (currently ignored)
+ * 0   : ended successfully
+ * 1   : for some reason the io has still not completed (eg,
+ *       multipath target might want to requeue a failed io).
+ * 2   : The target wants to push back the io
+ */
+typedef int (*dm_endio_fn) (struct dm_target *ti,
+			    struct bio *bio, int error);
+typedef int (*dm_request_endio_fn) (struct dm_target *ti,
+				    struct request *clone, int error,
+				    union map_info *map_context);
+
+typedef void (*dm_presuspend_fn) (struct dm_target *ti);
+typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
+typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
+typedef int (*dm_preresume_fn) (struct dm_target *ti);
+typedef void (*dm_resume_fn) (struct dm_target *ti);
+
+typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
+			      unsigned status_flags, char *result, unsigned maxlen);
+
+typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
+
+typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
+			    unsigned long arg);
+
+typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
+			    struct bio_vec *biovec, int max_size);
+
+/*
+ * These iteration functions are typically used to check (and combine)
+ * properties of underlying devices.
+ * E.g. Does at least one underlying device support flush?
+ *      Does any underlying device not support WRITE_SAME?
+ *
+ * The callout function is called once for each contiguous section of
+ * an underlying device.  State can be maintained in *data.
+ * Return non-zero to stop iterating through any further devices.
+ */
+typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
+					   struct dm_dev *dev,
+					   sector_t start, sector_t len,
+					   void *data);
+
+/*
+ * This function must iterate through each section of device used by the
+ * target until it encounters a non-zero return code, which it then returns.
+ * Returns zero if no callout returned non-zero.
+ */
+typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
+				      iterate_devices_callout_fn fn,
+				      void *data);
+
+typedef void (*dm_io_hints_fn) (struct dm_target *ti,
+				struct queue_limits *limits);
+
+/*
+ * Returns:
+ *    0: The target can handle the next I/O immediately.
+ *    1: The target can't handle the next I/O immediately.
+ */
+typedef int (*dm_busy_fn) (struct dm_target *ti);
+
+void dm_error(const char *message);
+
+struct dm_dev {
+	struct block_device *bdev;
+	fmode_t mode;
+	char name[16];
+};
+
+/*
+ * Constructors should call these functions to ensure destination devices
+ * are opened/closed correctly.
+ */
+int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
+		  struct dm_dev **result);
+void dm_put_device(struct dm_target *ti, struct dm_dev *d);
+
+/*
+ * Information about a target type
+ */
+
+struct target_type {
+	uint64_t features;
+	const char *name;
+	struct module *module;
+	unsigned version[3];
+	dm_ctr_fn ctr;
+	dm_dtr_fn dtr;
+	dm_map_fn map;
+	dm_map_request_fn map_rq;
+	dm_clone_and_map_request_fn clone_and_map_rq;
+	dm_release_clone_request_fn release_clone_rq;
+	dm_endio_fn end_io;
+	dm_request_endio_fn rq_end_io;
+	dm_presuspend_fn presuspend;
+	dm_presuspend_undo_fn presuspend_undo;
+	dm_postsuspend_fn postsuspend;
+	dm_preresume_fn preresume;
+	dm_resume_fn resume;
+	dm_status_fn status;
+	dm_message_fn message;
+	dm_ioctl_fn ioctl;
+	dm_merge_fn merge;
+	dm_busy_fn busy;
+	dm_iterate_devices_fn iterate_devices;
+	dm_io_hints_fn io_hints;
+
+	/* For internal device-mapper use. */
+	struct list_head list;
+};
+
+/*
+ * Target features
+ */
+
+/*
+ * Any table that contains an instance of this target must have only one.
+ */
+#define DM_TARGET_SINGLETON		0x00000001
+#define dm_target_needs_singleton(type)	((type)->features & DM_TARGET_SINGLETON)
+
+/*
+ * Indicates that a target does not support read-only devices.
+ */
+#define DM_TARGET_ALWAYS_WRITEABLE	0x00000002
+#define dm_target_always_writeable(type) \
+		((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
+
+/*
+ * Any device that contains a table with an instance of this target may never
+ * have tables containing any different target type.
+ */
+#define DM_TARGET_IMMUTABLE		0x00000004
+#define dm_target_is_immutable(type)	((type)->features & DM_TARGET_IMMUTABLE)
+
+/*
+ * Some targets need to be sent the same WRITE bio severals times so
+ * that they can send copies of it to different devices.  This function
+ * examines any supplied bio and returns the number of copies of it the
+ * target requires.
+ */
+typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);
+
+struct dm_target {
+	struct dm_table *table;
+	struct target_type *type;
+
+	/* target limits */
+	sector_t begin;
+	sector_t len;
+
+	/* If non-zero, maximum size of I/O submitted to a target. */
+	uint32_t max_io_len;
+
+	/*
+	 * A number of zero-length barrier bios that will be submitted
+	 * to the target for the purpose of flushing cache.
+	 *
+	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
+	 * It is a responsibility of the target driver to remap these bios
+	 * to the real underlying devices.
+	 */
+	unsigned num_flush_bios;
+
+	/*
+	 * The number of discard bios that will be submitted to the target.
+	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
+	 */
+	unsigned num_discard_bios;
+
+	/*
+	 * The number of WRITE SAME bios that will be submitted to the target.
+	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
+	 */
+	unsigned num_write_same_bios;
+
+	/*
+	 * The minimum number of extra bytes allocated in each bio for the
+	 * target to use.  dm_per_bio_data returns the data location.
+	 */
+	unsigned per_bio_data_size;
+
+	/*
+	 * If defined, this function is called to find out how many
+	 * duplicate bios should be sent to the target when writing
+	 * data.
+	 */
+	dm_num_write_bios_fn num_write_bios;
+
+	/* target specific data */
+	void *private;
+
+	/* Used to provide an error string from the ctr */
+	char *error;
+
+	/*
+	 * Set if this target needs to receive flushes regardless of
+	 * whether or not its underlying devices have support.
+	 */
+	bool flush_supported:1;
+
+	/*
+	 * Set if this target needs to receive discards regardless of
+	 * whether or not its underlying devices have support.
+	 */
+	bool discards_supported:1;
+
+	/*
+	 * Set if the target required discard bios to be split
+	 * on max_io_len boundary.
+	 */
+	bool split_discard_bios:1;
+
+	/*
+	 * Set if this target does not return zeroes on discarded blocks.
+	 */
+	bool discard_zeroes_data_unsupported:1;
+};
+
+/* Each target can link one of these into the table */
+struct dm_target_callbacks {
+	struct list_head list;
+	int (*congested_fn) (struct dm_target_callbacks *, int);
+};
+
+/*
+ * For bio-based dm.
+ * One of these is allocated for each bio.
+ * This structure shouldn't be touched directly by target drivers.
+ * It is here so that we can inline dm_per_bio_data and
+ * dm_bio_from_per_bio_data
+ */
+struct dm_target_io {
+	struct dm_io *io;
+	struct dm_target *ti;
+	unsigned target_bio_nr;
+	unsigned *len_ptr;
+	struct bio clone;
+};
+
+static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
+{
+	return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
+}
+
+static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
+{
+	return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
+}
+
+static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
+{
+	return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
+}
+
+int dm_register_target(struct target_type *t);
+void dm_unregister_target(struct target_type *t);
+
+/*
+ * Target argument parsing.
+ */
+struct dm_arg_set {
+	unsigned argc;
+	char **argv;
+};
+
+/*
+ * The minimum and maximum value of a numeric argument, together with
+ * the error message to use if the number is found to be outside that range.
+ */
+struct dm_arg {
+	unsigned min;
+	unsigned max;
+	char *error;
+};
+
+/*
+ * Validate the next argument, either returning it as *value or, if invalid,
+ * returning -EINVAL and setting *error.
+ */
+int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+		unsigned *value, char **error);
+
+/*
+ * Process the next argument as the start of a group containing between
+ * arg->min and arg->max further arguments. Either return the size as
+ * *num_args or, if invalid, return -EINVAL and set *error.
+ */
+int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
+		      unsigned *num_args, char **error);
+
+/*
+ * Return the current argument and shift to the next.
+ */
+const char *dm_shift_arg(struct dm_arg_set *as);
+
+/*
+ * Move through num_args arguments.
+ */
+void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
+
+/*-----------------------------------------------------------------
+ * Functions for creating and manipulating mapped devices.
+ * Drop the reference with dm_put when you finish with the object.
+ *---------------------------------------------------------------*/
+
+/*
+ * DM_ANY_MINOR chooses the next available minor number.
+ */
+#define DM_ANY_MINOR (-1)
+int dm_create(int minor, struct mapped_device **md);
+
+/*
+ * Reference counting for md.
+ */
+struct mapped_device *dm_get_md(dev_t dev);
+void dm_get(struct mapped_device *md);
+int dm_hold(struct mapped_device *md);
+void dm_put(struct mapped_device *md);
+
+/*
+ * An arbitrary pointer may be stored alongside a mapped device.
+ */
+void dm_set_mdptr(struct mapped_device *md, void *ptr);
+void *dm_get_mdptr(struct mapped_device *md);
+
+/*
+ * A device can still be used while suspended, but I/O is deferred.
+ */
+int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
+int dm_resume(struct mapped_device *md);
+
+/*
+ * Event functions.
+ */
+uint32_t dm_get_event_nr(struct mapped_device *md);
+int dm_wait_event(struct mapped_device *md, int event_nr);
+uint32_t dm_next_uevent_seq(struct mapped_device *md);
+void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
+
+/*
+ * Info functions.
+ */
+const char *dm_device_name(struct mapped_device *md);
+int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
+struct gendisk *dm_disk(struct mapped_device *md);
+int dm_suspended(struct dm_target *ti);
+int dm_noflush_suspending(struct dm_target *ti);
+void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
+union map_info *dm_get_rq_mapinfo(struct request *rq);
+
+struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
+
+/*
+ * Geometry functions.
+ */
+int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
+int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
+
+/*-----------------------------------------------------------------
+ * Functions for manipulating device-mapper tables.
+ *---------------------------------------------------------------*/
+
+/*
+ * First create an empty table.
+ */
+int dm_table_create(struct dm_table **result, fmode_t mode,
+		    unsigned num_targets, struct mapped_device *md);
+
+/*
+ * Then call this once for each target.
+ */
+int dm_table_add_target(struct dm_table *t, const char *type,
+			sector_t start, sector_t len, char *params);
+
+/*
+ * Target_ctr should call this if it needs to add any callbacks.
+ */
+void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
+
+/*
+ * Finally call this to make the table ready for use.
+ */
+int dm_table_complete(struct dm_table *t);
+
+/*
+ * Target may require that it is never sent I/O larger than len.
+ */
+int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
+
+/*
+ * Table reference counting.
+ */
+struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
+void dm_put_live_table(struct mapped_device *md, int srcu_idx);
+void dm_sync_table(struct mapped_device *md);
+
+/*
+ * Queries
+ */
+sector_t dm_table_get_size(struct dm_table *t);
+unsigned int dm_table_get_num_targets(struct dm_table *t);
+fmode_t dm_table_get_mode(struct dm_table *t);
+struct mapped_device *dm_table_get_md(struct dm_table *t);
+
+/*
+ * Trigger an event.
+ */
+void dm_table_event(struct dm_table *t);
+
+/*
+ * Run the queue for request-based targets.
+ */
+void dm_table_run_md_queue_async(struct dm_table *t);
+
+/*
+ * The device must be suspended before calling this method.
+ * Returns the previous table, which the caller must destroy.
+ */
+struct dm_table *dm_swap_table(struct mapped_device *md,
+			       struct dm_table *t);
+
+/*
+ * A wrapper around vmalloc.
+ */
+void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
+
+/*-----------------------------------------------------------------
+ * Macros.
+ *---------------------------------------------------------------*/
+#define DM_NAME "device-mapper"
+
+#ifdef CONFIG_PRINTK
+extern struct ratelimit_state dm_ratelimit_state;
+
+#define dm_ratelimit()	__ratelimit(&dm_ratelimit_state)
+#else
+#define dm_ratelimit()	0
+#endif
+
+#define DMCRIT(f, arg...) \
+	printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
+
+#define DMERR(f, arg...) \
+	printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
+#define DMERR_LIMIT(f, arg...) \
+	do { \
+		if (dm_ratelimit())	\
+			printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
+			       f "\n", ## arg); \
+	} while (0)
+
+#define DMWARN(f, arg...) \
+	printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
+#define DMWARN_LIMIT(f, arg...) \
+	do { \
+		if (dm_ratelimit())	\
+			printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
+			       f "\n", ## arg); \
+	} while (0)
+
+#define DMINFO(f, arg...) \
+	printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
+#define DMINFO_LIMIT(f, arg...) \
+	do { \
+		if (dm_ratelimit())	\
+			printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
+			       "\n", ## arg); \
+	} while (0)
+
+#ifdef CONFIG_DM_DEBUG
+#  define DMDEBUG(f, arg...) \
+	printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
+#  define DMDEBUG_LIMIT(f, arg...) \
+	do { \
+		if (dm_ratelimit())	\
+			printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
+			       "\n", ## arg); \
+	} while (0)
+#else
+#  define DMDEBUG(f, arg...) do {} while (0)
+#  define DMDEBUG_LIMIT(f, arg...) do {} while (0)
+#endif
+
+#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
+			  0 : scnprintf(result + sz, maxlen - sz, x))
+
+#define SECTOR_SHIFT 9
+
+/*
+ * Definitions of return values from target end_io function.
+ */
+#define DM_ENDIO_INCOMPLETE	1
+#define DM_ENDIO_REQUEUE	2
+
+/*
+ * Definitions of return values from target map function.
+ */
+#define DM_MAPIO_SUBMITTED	0
+#define DM_MAPIO_REMAPPED	1
+#define DM_MAPIO_REQUEUE	DM_ENDIO_REQUEUE
+
+#define dm_sector_div64(x, y)( \
+{ \
+	u64 _res; \
+	(x) = div64_u64_rem(x, y, &_res); \
+	_res; \
+} \
+)
+
+/*
+ * Ceiling(n / sz)
+ */
+#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
+
+#define dm_sector_div_up(n, sz) ( \
+{ \
+	sector_t _r = ((n) + (sz) - 1); \
+	sector_div(_r, (sz)); \
+	_r; \
+} \
+)
+
+/*
+ * ceiling(n / size) * size
+ */
+#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
+
+#define dm_array_too_big(fixed, obj, num) \
+	((num) > (UINT_MAX - (fixed)) / (obj))
+
+/*
+ * Sector offset taken relative to the start of the target instead of
+ * relative to the start of the device.
+ */
+#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
+
+static inline sector_t to_sector(unsigned long n)
+{
+	return (n >> SECTOR_SHIFT);
+}
+
+static inline unsigned long to_bytes(sector_t n)
+{
+	return (n << SECTOR_SHIFT);
+}
+
+#endif	/* _LINUX_DEVICE_MAPPER_H */