Add action=spare-same-slot policy.

[thirdparty/mdadm.git] / mdadm.h

/*
 * mdadm - manage Linux "md" devices aka RAID arrays.
 *
 * Copyright (C) 2001-2009 Neil Brown <neilb@suse.de>
 *
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *    Author: Neil Brown
 *    Email: <neilb@suse.de>
 */

#define _GNU_SOURCE
#define _FILE_OFFSET_BITS 64
#include        <unistd.h>
#if !defined(__dietlibc__) && !defined(__KLIBC__)
extern __off64_t lseek64 __P ((int __fd, __off64_t __offset, int __whence));
#else
# if defined(__NO_STAT64) || __WORDSIZE != 32
# define lseek64 lseek
# endif
#endif

#include        <sys/types.h>
#include        <sys/stat.h>
#include        <stdlib.h>
#include        <time.h>
#include        <sys/time.h>
#include        <getopt.h>
#include        <fcntl.h>
#include        <stdio.h>
#include        <errno.h>
#include        <string.h>
#include        <syslog.h>
#ifdef __dietlibc__
#include        <strings.h>
/* dietlibc has deprecated random and srandom!! */
#define random rand
#define srandom srand
#endif


#include        <linux/kdev_t.h>
/*#include      <linux/fs.h> */
#include        <sys/mount.h>
#include        <asm/types.h>
#include        <sys/ioctl.h>
#define MD_MAJOR 9
#define MdpMinorShift 6

#ifndef BLKGETSIZE64
#define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
#endif

#define DEFAULT_BITMAP_CHUNK 4096
#define DEFAULT_BITMAP_DELAY 5
#define DEFAULT_MAX_WRITE_BEHIND 256

/* MAP_DIR should be somewhere that persists across the pivotroot
 * from early boot to late boot.
 * Currently /dev seems to be the only option on most distros.
 */
#ifndef MAP_DIR
#define MAP_DIR "/dev/.mdadm"
#endif /* MAP_DIR */
/* MAP_FILE is what we name the map file we put in MAP_DIR, in case you
 * want something other than the default of "map"
 */
#ifndef MAP_FILE
#define MAP_FILE "map"
#endif /* MAP_FILE */
/* MDMON_DIR is where pid and socket files used for communicating
 * with mdmon normally live.  It *should* be /var/run, but when
 * mdmon is needed at early boot then it needs to write there prior
 * to /var/run being mounted read/write, and it also then needs to
 * persist beyond when /var/run is mounter read-only.  So, to be
 * safe, the default is somewhere that is read/write early in the
 * boot process and stays up as long as possible during shutdown.
 */
#ifndef MDMON_DIR
#define MDMON_DIR "/dev/.mdadm/"
#endif /* MDMON_DIR */

/* FAILED_SLOTS is where to save files storing recent removal of array
 * member in order to allow future reuse of disk inserted in the same
 * slot for array recovery
 */
#ifndef FAILED_SLOTS_DIR
#define FAILED_SLOTS_DIR "/dev/.mdadm/failed-slots"
#endif /* FAILED_SLOTS */

#include        "md_u.h"
#include        "md_p.h"
#include        "bitmap.h"
#include        "msg.h"

#include <endian.h>
/* Redhat don't like to #include <asm/byteorder.h>, and
 * some time include <linux/byteorder/xxx_endian.h> isn't enough,
 * and there is no standard conversion function so... */
/* And dietlibc doesn't think byteswap is ok, so.. */
/*  #include <byteswap.h> */
#define bswap_16(x) (((x) & 0x00ffU) << 8 | \
                     ((x) & 0xff00U) >> 8)
#define bswap_32(x) (((x) & 0x000000ffU) << 24 | \
                     ((x) & 0xff000000U) >> 24 | \
                     ((x) & 0x0000ff00U) << 8  | \
                     ((x) & 0x00ff0000U) >> 8)
#define bswap_64(x) (((x) & 0x00000000000000ffULL) << 56 | \
                     ((x) & 0xff00000000000000ULL) >> 56 | \
                     ((x) & 0x000000000000ff00ULL) << 40 | \
                     ((x) & 0x00ff000000000000ULL) >> 40 | \
                     ((x) & 0x0000000000ff0000ULL) << 24 | \
                     ((x) & 0x0000ff0000000000ULL) >> 24 | \
                     ((x) & 0x00000000ff000000ULL) << 8 | \
                     ((x) & 0x000000ff00000000ULL) >> 8)

#if !defined(__KLIBC__)
#if BYTE_ORDER == LITTLE_ENDIAN
#define __cpu_to_le16(_x) (_x)
#define __cpu_to_le32(_x) (_x)
#define __cpu_to_le64(_x) (_x)
#define __le16_to_cpu(_x) (_x)
#define __le32_to_cpu(_x) (_x)
#define __le64_to_cpu(_x) (_x)

#define __cpu_to_be16(_x) bswap_16(_x)
#define __cpu_to_be32(_x) bswap_32(_x)
#define __cpu_to_be64(_x) bswap_64(_x)
#define __be16_to_cpu(_x) bswap_16(_x)
#define __be32_to_cpu(_x) bswap_32(_x)
#define __be64_to_cpu(_x) bswap_64(_x)
#elif BYTE_ORDER == BIG_ENDIAN
#define __cpu_to_le16(_x) bswap_16(_x)
#define __cpu_to_le32(_x) bswap_32(_x)
#define __cpu_to_le64(_x) bswap_64(_x)
#define __le16_to_cpu(_x) bswap_16(_x)
#define __le32_to_cpu(_x) bswap_32(_x)
#define __le64_to_cpu(_x) bswap_64(_x)

#define __cpu_to_be16(_x) (_x)
#define __cpu_to_be32(_x) (_x)
#define __cpu_to_be64(_x) (_x)
#define __be16_to_cpu(_x) (_x)
#define __be32_to_cpu(_x) (_x)
#define __be64_to_cpu(_x) (_x)
#else
#  error "unknown endianness."
#endif
#endif /* __KLIBC__ */


/*
 * min()/max()/clamp() macros that also do
 * strict type-checking.. See the
 * "unnecessary" pointer comparison.
 */
#define min(x, y) ({                            \
        typeof(x) _min1 = (x);                  \
        typeof(y) _min2 = (y);                  \
        (void) (&_min1 == &_min2);              \
        _min1 < _min2 ? _min1 : _min2; })

#define max(x, y) ({                            \
        typeof(x) _max1 = (x);                  \
        typeof(y) _max2 = (y);                  \
        (void) (&_max1 == &_max2);              \
        _max1 > _max2 ? _max1 : _max2; })

/* general information that might be extracted from a superblock */
struct mdinfo {
        mdu_array_info_t        array;
        mdu_disk_info_t         disk;
        __u64                   events;
        int                     uuid[4];
        char                    name[33];
        unsigned long long      data_offset;
        unsigned long long      component_size; /* same as array.size, except in
                                                 * sectors and up to 64bits.
                                                 */
        unsigned long long      custom_array_size; /* size for non-default sized
                                                    * arrays (in sectors)
                                                    */
        int                     reshape_active;
        unsigned long long      reshape_progress;
        union {
                unsigned long long resync_start; /* per-array resync position */
                unsigned long long recovery_start; /* per-device rebuild position */
                #define MaxSector  (~0ULL) /* resync/recovery complete position */
        };
        unsigned long           safe_mode_delay; /* ms delay to mark clean */
        int                     new_level, delta_disks, new_layout, new_chunk;
        int                     errors;
        unsigned long           cache_size; /* size of raid456 stripe cache*/
        int                     mismatch_cnt;
        char                    text_version[50];
        void                    *update_private; /* for passing metadata-format
                                                  * specific update data
                                                  * between successive calls to
                                                  * update_super()
                                                  */

        int container_member; /* for assembling external-metatdata arrays
                               * This is to be used internally by metadata
                               * handler only */
        int container_enough; /* flag external handlers can set to
                               * indicate that subarrays have not enough (-1),
                               * enough to start (0), or all expected disks (1) */
        char            sys_name[20];
        struct mdinfo *devs;
        struct mdinfo *next;

        /* Device info for mdmon: */
        int recovery_fd;
        int state_fd;
        #define DS_FAULTY       1
        #define DS_INSYNC       2
        #define DS_WRITE_MOSTLY 4
        #define DS_SPARE        8
        #define DS_BLOCKED      16
        #define DS_REMOVE       1024
        #define DS_UNBLOCK      2048
        int prev_state, curr_state, next_state;

};

struct createinfo {
        int     uid;
        int     gid;
        int     autof;
        int     mode;
        int     symlinks;
        struct supertype *supertype;
};

#define Name "mdadm"

enum mode {
        ASSEMBLE=1,
        BUILD,
        CREATE,
        MANAGE,
        MISC,
        MONITOR,
        GROW,
        INCREMENTAL,
        AUTODETECT,
};

extern char short_options[];
extern char short_bitmap_options[];
extern char short_bitmap_auto_options[];
extern struct option long_options[];
extern char Version[], Usage[], Help[], OptionHelp[],
        Help_create[], Help_build[], Help_assemble[], Help_grow[],
        Help_incr[],
        Help_manage[], Help_misc[], Help_monitor[], Help_config[];

/* for option that don't have short equivilents, we assign arbitrary
 * small numbers.  '1' means an undecorated option, so we start at '2'.
 * (note we must stop before we get to 65 i.e. 'A')
 */
enum special_options {
        AssumeClean = 2,
        BitmapChunk,
        WriteBehind,
        ReAdd,
        NoDegraded,
        Sparc22,
        BackupFile, /* 8 */
        HomeHost,
        AutoHomeHost,
        Symlinks,
        AutoDetect,
        Waitclean,
        DetailPlatform,
        KillSubarray,
        UpdateSubarray, /* 16 */
        IncrementalPath
};

/* structures read from config file */
/* List of mddevice names and identifiers
 * Identifiers can be:
 *    uuid=128-hex-uuid
 *    super-minor=decimal-minor-number-from-superblock
 *    devices=comma,separated,list,of,device,names,with,wildcards
 *
 * If multiple fields are present, the intersection of all matching
 * devices is considered
 */
#define UnSet (0xfffe)
struct mddev_ident {
        char    *devname;

        int     uuid_set;
        int     uuid[4];
        char    name[33];

        int super_minor;

        char    *devices;       /* comma separated list of device
                                 * names with wild cards
                                 */
        int     level;
        int raid_disks;
        int spare_disks;
        struct supertype *st;
        int     autof;          /* 1 for normal, 2 for partitioned */
        char    *spare_group;
        char    *bitmap_file;
        int     bitmap_fd;

        char    *container;     /* /dev/whatever name of container, or
                                 * uuid of container.  You would expect
                                 * this to be the 'devname' or UUID
                                 * of some other entry.
                                 */
        char    *member;        /* subarray within a container */

        struct mddev_ident *next;
        union {
                /* fields needed by different users of this structure */
                int assembled;  /* set when assembly succeeds */
        };
};

/* List of device names - wildcards expanded */
struct mddev_dev {
        char *devname;
        char disposition;       /* 'a' for add, 'r' for remove, 'f' for fail.
                                 * Not set for names read from .config
                                 */
        char writemostly;       /* 1 for 'set writemostly', 2 for 'clear writemostly' */
        char re_add;
        char used;              /* set when used */
        struct mddev_dev *next;
};

typedef struct mapping {
        char *name;
        int num;
} mapping_t;


struct mdstat_ent {
        char            *dev;
        int             devnum;
        int             active;
        char            *level;
        char            *pattern; /* U or up, _ for down */
        int             percent; /* -1 if no resync */
        int             resync; /* 3 if check, 2 if reshape, 1 if resync, 0 if recovery */
        int             devcnt;
        int             raid_disks;
        int             chunk_size;
        char *          metadata_version;
        struct dev_member {
                char                    *name;
                struct dev_member       *next;
        }               *members;
        struct mdstat_ent *next;
};

extern struct mdstat_ent *mdstat_read(int hold, int start);
extern void free_mdstat(struct mdstat_ent *ms);
extern void mdstat_wait(int seconds);
extern void mdstat_wait_fd(int fd, const sigset_t *sigmask);
extern int mddev_busy(int devnum);
extern struct mdstat_ent *mdstat_by_component(char *name);

struct map_ent {
        struct map_ent *next;
        int     devnum;
        char    metadata[20];
        int     uuid[4];
        int     bad;
        char    *path;
};
extern int map_update(struct map_ent **mpp, int devnum, char *metadata,
                      int uuid[4], char *path);
extern void map_remove(struct map_ent **map, int devnum);
extern struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4]);
extern struct map_ent *map_by_devnum(struct map_ent **map, int devnum);
extern struct map_ent *map_by_name(struct map_ent **map, char *name);
extern void map_read(struct map_ent **melp);
extern int map_write(struct map_ent *mel);
extern void map_delete(struct map_ent **mapp, int devnum);
extern void map_free(struct map_ent *map);
extern void map_add(struct map_ent **melp,
                    int devnum, char *metadata, int uuid[4], char *path);
extern int map_lock(struct map_ent **melp);
extern void map_unlock(struct map_ent **melp);

/* various details can be requested */
enum sysfs_read_flags {
        GET_LEVEL       = (1 << 0),
        GET_LAYOUT      = (1 << 1),
        GET_COMPONENT   = (1 << 2),
        GET_CHUNK       = (1 << 3),
        GET_CACHE       = (1 << 4),
        GET_MISMATCH    = (1 << 5),
        GET_VERSION     = (1 << 6),
        GET_DISKS       = (1 << 7),
        GET_DEGRADED    = (1 << 8),
        GET_SAFEMODE    = (1 << 9),
        GET_DEVS        = (1 << 10), /* gets role, major, minor */
        GET_OFFSET      = (1 << 11),
        GET_SIZE        = (1 << 12),
        GET_STATE       = (1 << 13),
        GET_ERROR       = (1 << 14),
};

/* If fd >= 0, get the array it is open on,
 * else use devnum. >=0 -> major9. <0.....
 */
extern int sysfs_open(int devnum, char *devname, char *attr);
extern void sysfs_init(struct mdinfo *mdi, int fd, int devnum);
extern void sysfs_free(struct mdinfo *sra);
extern struct mdinfo *sysfs_read(int fd, int devnum, unsigned long options);
extern int sysfs_attr_match(const char *attr, const char *str);
extern int sysfs_match_word(const char *word, char **list);
extern int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
                         char *name, char *val);
extern int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
                         char *name, unsigned long long val);
extern int sysfs_uevent(struct mdinfo *sra, char *event);
extern int sysfs_get_fd(struct mdinfo *sra, struct mdinfo *dev,
                        char *name);
extern int sysfs_fd_get_ll(int fd, unsigned long long *val);
extern int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
                        char *name, unsigned long long *val);
extern int sysfs_fd_get_str(int fd, char *val, int size);
extern int sysfs_get_str(struct mdinfo *sra, struct mdinfo *dev,
                         char *name, char *val, int size);
extern int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms);
extern int sysfs_set_array(struct mdinfo *info, int vers);
extern int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume);
extern int sysfs_disk_to_scsi_id(int fd, __u32 *id);
extern int sysfs_unique_holder(int devnum, long rdev);
extern int load_sys(char *path, char *buf);


extern int save_stripes(int *source, unsigned long long *offsets,
                        int raid_disks, int chunk_size, int level, int layout,
                        int nwrites, int *dest,
                        unsigned long long start, unsigned long long length,
                        char *buf);
extern int restore_stripes(int *dest, unsigned long long *offsets,
                           int raid_disks, int chunk_size, int level, int layout,
                           int source, unsigned long long read_offset,
                           unsigned long long start, unsigned long long length);

#ifndef Sendmail
#define Sendmail "/usr/lib/sendmail -t"
#endif

#define SYSLOG_FACILITY LOG_DAEMON

extern char *map_num(mapping_t *map, int num);
extern int map_name(mapping_t *map, char *name);
extern mapping_t r5layout[], r6layout[], pers[], modes[], faultylayout[];

extern char *map_dev(int major, int minor, int create);

struct active_array;
struct metadata_update;

/* A superswitch provides entry point the a metadata handler.
 *
 * The super_switch primarily operates on some "metadata" that
 * is accessed via the 'supertype'.
 * This metadata has one of three possible sources.
 * 1/ It is read from a single device.  In this case it may not completely
 *    describe the array or arrays as some information might be on other
 *    devices.
 * 2/ It is read from all devices in a container.  In this case all
 *    information is present.
 * 3/ It is created by ->init_super / ->add_to_super.  In this case it will
 *    be complete once enough ->add_to_super calls have completed.
 *
 * When creating an array inside a container, the metadata will be
 * formed by a combination of 2 and 3.  The metadata or the array is read,
 * then new information is added.
 *
 * The metadata must sometimes have a concept of a 'current' array
 * and a 'current' device.
 * The 'current' array is set by init_super to be the newly created array,
 * or is set by super_by_fd when it finds it is looking at an array inside
 * a container.
 *
 * The 'current' device is either the device that the metadata was read from
 * in case 1, or the last device added by add_to_super in case 3.
 * Case 2 does not identify a 'current' device.
 */
extern struct superswitch {

        /* Used to report details of metadata read from a component
         * device. ->load_super has been called.
         */
        void (*examine_super)(struct supertype *st, char *homehost);
        void (*brief_examine_super)(struct supertype *st, int verbose);
        void (*brief_examine_subarrays)(struct supertype *st, int verbose);
        void (*export_examine_super)(struct supertype *st);

        /* Used to report details of an active array.
         * ->load_super was possibly given a 'component' string.
         */
        void (*detail_super)(struct supertype *st, char *homehost);
        void (*brief_detail_super)(struct supertype *st);
        void (*export_detail_super)(struct supertype *st);

        /* Optional: platform hardware / firmware details */
        int (*detail_platform)(int verbose, int enumerate_only);

        /* Used:
         *   to get uuid to storing in bitmap metadata
         *   and 'reshape' backup-data metadata
         *   To see if a device is being re-added to an array it was part of.
         */
        void (*uuid_from_super)(struct supertype *st, int uuid[4]);

        /* Extract generic details from metadata.  This could be details about
         * the container, or about an individual array within the container.
         * The determination is made either by:
         *   load_super being given a 'component' string.
         *   validate_geometry determining what to create.
         * The info includes both array information and device information.
         * The particular device should be:
         *   The last device added by add_to_super
         *   The device the metadata was loaded from by load_super
         * If 'map' is present, then it is an array raid_disks long
         * (raid_disk must already be set and correct) and it is filled
         * with 1 for slots that are thought to be active and 0 for slots which
         * appear to be failed/missing.
         */
        void (*getinfo_super)(struct supertype *st, struct mdinfo *info, char *map);

        /* Check if the given metadata is flagged as belonging to "this"
         * host.  0 for 'no', 1 for 'yes', -1 for "Don't record homehost"
         */
        int (*match_home)(struct supertype *st, char *homehost);

        /* Make one of several generic modifications to metadata
         * prior to assembly (or other times).
         *   sparc2.2  - first bug in early 0.90 metadata
         *   super-minor - change name of 0.90 metadata
         *   summaries - 'correct' any redundant data
         *   resync - mark array as dirty to trigger a resync.
         *   uuid - set new uuid - only 0.90 or 1.x
         *   name - change the name of the array (where supported)
         *   homehost - change which host this array is tied to.
         *   devicesize - If metadata is at start of device, change recorded
         *               device size to match actual device size
         *   byteorder - swap bytes for 0.90 metadata
         *
         *   force-one  - mark that device as uptodate, not old or failed.
         *   force-array - mark array as clean if it would not otherwise
         *               assemble
         *   assemble   - not sure how this is different from force-one...
         *   linear-grow-new - add a new device to a linear array, but don't
         *                   change the size: so superblock still matches
         *   linear-grow-update - now change the size of the array.
         */
        int (*update_super)(struct supertype *st, struct mdinfo *info,
                            char *update,
                            char *devname, int verbose,
                            int uuid_set, char *homehost);

        /* Create new metadata for new array as described.  This could
         * be a new container, or an array in a pre-existing container.
         * Also used to zero metadata prior to writing it to invalidate old
         * metadata.
         */
        int (*init_super)(struct supertype *st, mdu_array_info_t *info,
                          unsigned long long size, char *name,
                          char *homehost, int *uuid);

        /* update the metadata to include new device, either at create or
         * when hot-adding a spare.
         */
        int (*add_to_super)(struct supertype *st, mdu_disk_info_t *dinfo,
                             int fd, char *devname);

        /* Write metadata to one device when fixing problems or adding
         * a new device.
         */
        int (*store_super)(struct supertype *st, int fd);

        /*  Write all metadata for this array.
         */
        int (*write_init_super)(struct supertype *st);
        int (*compare_super)(struct supertype *st, struct supertype *tst);
        int (*load_super)(struct supertype *st, int fd, char *devname);
        int (*load_container)(struct supertype *st, int fd, char *devname);
        struct supertype * (*match_metadata_desc)(char *arg);
        __u64 (*avail_size)(struct supertype *st, __u64 size);
        int (*add_internal_bitmap)(struct supertype *st, int *chunkp,
                                   int delay, int write_behind,
                                   unsigned long long size, int may_change, int major);
        void (*locate_bitmap)(struct supertype *st, int fd);
        int (*write_bitmap)(struct supertype *st, int fd);
        void (*free_super)(struct supertype *st);

        /* validate_geometry is called with an st returned by
         * match_metadata_desc.
         * It should check that the geometry described in compatible with
         * the metadata type.  It will be called repeatedly as devices
         * added to validate changing size and new devices.  If there are
         * inter-device dependencies, it should record sufficient details
         * so these can be validated.
         * Both 'size' and '*freesize' are in sectors.  chunk is bytes.
         */
        int (*validate_geometry)(struct supertype *st, int level, int layout,
                                 int raiddisks,
                                 int chunk, unsigned long long size,
                                 char *subdev, unsigned long long *freesize,
                                 int verbose);

        struct mdinfo *(*container_content)(struct supertype *st, char *subarray);
        /* Allow a metadata handler to override mdadm's default layouts */
        int (*default_layout)(int level); /* optional */
        /* query the supertype for default chunk size */
        int (*default_chunk)(struct supertype *st); /* optional */
        /* Permit subarray's to be deleted from inactive containers */
        int (*kill_subarray)(struct supertype *st); /* optional */
        /* Permit subarray's to be modified */
        int (*update_subarray)(struct supertype *st, char *subarray,
                               char *update, struct mddev_ident *ident); /* optional */

/* for mdmon */
        int (*open_new)(struct supertype *c, struct active_array *a,
                        char *inst);

        /* Tell the metadata handler the current state of the array.
         * This covers whether it is known to be consistent (no pending writes)
         * and how far along a resync is known to have progressed
         * (in a->resync_start).
         * resync status is really irrelevant if the array is not consistent,
         * but some metadata (DDF!) have a place to record the distinction.
         * If 'consistent' is '2', then the array can mark it dirty if a 
         * resync/recovery/whatever is required, or leave it clean if not.
         * Return value is 0 dirty (not consistent) and 1 if clean.
         * it is only really important if consistent is passed in as '2'.
         */
        int (*set_array_state)(struct active_array *a, int consistent);

        /* When the state of a device might have changed, we call set_disk to
         * tell the metadata what the current state is.
         * Typically this happens on spare->in_sync and (spare|in_sync)->faulty
         * transitions.
         * set_disk might be called when the state of the particular disk has
         * not in fact changed.
         */
        void (*set_disk)(struct active_array *a, int n, int state);
        void (*sync_metadata)(struct supertype *st);
        void (*process_update)(struct supertype *st,
                               struct metadata_update *update);
        void (*prepare_update)(struct supertype *st,
                               struct metadata_update *update);

        /* activate_spare will check if the array is degraded and, if it
         * is, try to find some spare space in the container.
         * On success, it add appropriate updates (For process_update) to
         * to the 'updates' list and returns a list of 'mdinfo' identifying
         * the device, or devices as there might be multiple missing
         * devices and multiple spares available.
         */
        struct mdinfo *(*activate_spare)(struct active_array *a,
                                         struct metadata_update **updates);

        int swapuuid; /* true if uuid is bigending rather than hostendian */
        int external;
        const char *name; /* canonical metadata name */
} *superlist[];

extern struct superswitch super0, super1;
extern struct superswitch super_imsm, super_ddf;
extern struct superswitch mbr, gpt;

struct metadata_update {
        int     len;
        char    *buf;
        void    *space; /* allocated space that monitor will use */
        struct metadata_update *next;
};

/* A supertype holds a particular collection of metadata.
 * It identifies the metadata type by the superswitch, and the particular
 * sub-version of that metadata type.
 * metadata read in or created is stored in 'sb' and 'info'.
 * There are also fields used by mdmon to track containers.
 *
 * A supertype may refer to:
 *   Just an array, possibly in a container
 *   A container, not identifying any particular array
 *   Info read from just one device, not yet fully describing the array/container.
 *
 *
 * A supertype is created by:
 *   super_by_fd
 *   guess_super
 *   dup_super
 */
struct supertype {
        struct superswitch *ss;
        int minor_version;
        int max_devs;
        int container_dev;    /* devnum of container */
        void *sb;
        void *info;

        struct metadata_update *updates;
        struct metadata_update **update_tail;

        /* extra stuff used by mdmon */
        struct active_array *arrays;
        int sock; /* listen to external programs */
        int devnum;
        char *devname; /* e.g. md0.  This appears in metadata_verison:
                        *  external:/md0/12
                        */
        int devcnt;

        struct mdinfo *devs;

};

extern struct supertype *super_by_fd(int fd, char **subarray);
enum guess_types { guess_any, guess_array, guess_partitions };
extern struct supertype *guess_super_type(int fd, enum guess_types guess_type);
static inline struct supertype *guess_super(int fd) {
        return guess_super_type(fd, guess_any);
}
extern struct supertype *dup_super(struct supertype *st);
extern int get_dev_size(int fd, char *dname, unsigned long long *sizep);
extern int must_be_container(int fd);
extern void get_one_disk(int mdfd, mdu_array_info_t *ainf,
                         mdu_disk_info_t *disk);
void wait_for(char *dev, int fd);

/*
 * Data structures for policy management.
 * Each device can have a policy structure that lists
 * various name/value pairs each possibly with a metadata associated.
 * The policy list is sorted by name/value/metadata
 */
struct dev_policy {
        struct dev_policy *next;
        char *name;     /* None of these strings are allocated.  They are
                         * all just references to strings which are known
                         * to exist elsewhere.
                         * name and metadata can be compared by address equality.
                         */
        const char *metadata;
        char *value;
};

extern char pol_act[], pol_domain[], pol_metadata[], pol_auto[];

/* iterate over the sublist starting at list, having the same
 * 'name' as 'list', and matching the given metadata (Where
 * NULL matches anything
 */
#define pol_for_each(item, list, _metadata)                             \
        for (item = list;                                               \
             item && item->name == list->name;                          \
             item = item->next)                                         \
                if (!(!_metadata || !item->metadata || _metadata == item->metadata)) \
                        ; else

/*
 * policy records read from mdadm are largely just name-value pairs.
 * The names are constants, not strdupped
 */
struct pol_rule {
        struct pol_rule *next;
        char *type;     /* rule_policy or rule_part */
        struct rule {
                struct rule *next;
                char *name;
                char *value;
                char *dups; /* duplicates of 'value' with a partNN appended */
        } *rule;
};

extern char rule_policy[], rule_part[];
extern char rule_path[], rule_type[];
extern char type_part[], type_disk[];

extern void policyline(char *line, char *type);
extern void policy_add(char *type, ...);
extern void policy_free(void);

extern struct dev_policy *path_policy(char *path, char *type);
extern struct dev_policy *disk_policy(struct mdinfo *disk);
extern struct dev_policy *devnum_policy(int dev);
extern void dev_policy_free(struct dev_policy *p);

extern void pol_new(struct dev_policy **pol, char *name, char *val, char *metadata);
extern struct dev_policy *pol_find(struct dev_policy *pol, char *name);

enum policy_action {
        act_default,
        act_include,
        act_re_add,
        act_spare,      /* This only applies to bare devices */
        act_spare_same_slot, /* this allows non-bare devices,
                              * but only if recent removal */
        act_force_spare, /* this allow non-bare devices in any case */
        act_err
};

extern int policy_action_allows(struct dev_policy *plist, const char *metadata,
                                enum policy_action want);
extern int disk_action_allows(struct mdinfo *disk, const char *metadata,
                              enum policy_action want);

struct domainlist {
        struct domainlist *next;
        char *dom;
};

extern int domain_test(struct domainlist *dom, struct dev_policy *pol,
                       const char *metadata);
extern struct domainlist *domain_from_array(struct mdinfo *mdi,
                                            const char *metadata);
extern void domain_free(struct domainlist *dl);
extern void domain_merge(struct domainlist **domp, struct dev_policy *pol,
                         const char *metadata);

extern void policy_save_path(char *id_path, struct map_ent *array);
extern int policy_check_path(struct mdinfo *disk, struct map_ent *array);

#if __GNUC__ < 3
struct stat64;
#endif

#define HAVE_NFTW  we assume
#define HAVE_FTW

#ifdef __UCLIBC__
# include <features.h>
# ifndef __UCLIBC_HAS_LFS__
#  define lseek64 lseek
# endif
# ifndef  __UCLIBC_HAS_FTW__
#  undef HAVE_FTW
#  undef HAVE_NFTW
# endif
#endif

#ifdef __dietlibc__
# undef HAVE_NFTW
#endif

#if defined(__KLIBC__)
# undef HAVE_NFTW
# undef HAVE_FTW
#endif

#ifndef HAVE_NFTW
# define FTW_PHYS 1
# ifndef HAVE_FTW
  struct FTW {};
# endif
#endif

#ifdef HAVE_FTW
# include <ftw.h>
#endif

extern int add_dev(const char *name, const struct stat *stb, int flag, struct FTW *s);


extern int Manage_ro(char *devname, int fd, int readonly);
extern int Manage_runstop(char *devname, int fd, int runstop, int quiet);
extern int Manage_resize(char *devname, int fd, long long size, int raid_disks);
extern int Manage_subdevs(char *devname, int fd,
                          struct mddev_dev *devlist, int verbose, int test);
extern int autodetect(void);
extern int Grow_Add_device(char *devname, int fd, char *newdev);
extern int Grow_addbitmap(char *devname, int fd, char *file, int chunk, int delay, int write_behind, int force);
extern int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
                        long long size,
                        int level, char *layout_str, int chunksize, int raid_disks);
extern int Grow_restart(struct supertype *st, struct mdinfo *info,
                        int *fdlist, int cnt, char *backup_file, int verbose);
extern int Grow_continue(int mdfd, struct supertype *st,
                         struct mdinfo *info, char *backup_file);

extern int Assemble(struct supertype *st, char *mddev,
                    struct mddev_ident *ident,
                    struct mddev_dev *devlist, char *backup_file,
                    int readonly, int runstop,
                    char *update, char *homehost, int require_homehost,
                    int verbose, int force);

extern int Build(char *mddev, int chunk, int level, int layout,
                 int raiddisks, struct mddev_dev *devlist, int assume_clean,
                 char *bitmap_file, int bitmap_chunk, int write_behind,
                 int delay, int verbose, int autof, unsigned long long size);


extern int Create(struct supertype *st, char *mddev,
                  int chunk, int level, int layout, unsigned long long size, int raiddisks, int sparedisks,
                  char *name, char *homehost, int *uuid,
                  int subdevs, struct mddev_dev *devlist,
                  int runstop, int verbose, int force, int assume_clean,
                  char *bitmap_file, int bitmap_chunk, int write_behind, int delay, int autof);

extern int Detail(char *dev, int brief, int export, int test, char *homehost);
extern int Detail_Platform(struct superswitch *ss, int scan, int verbose);
extern int Query(char *dev);
extern int Examine(struct mddev_dev *devlist, int brief, int export, int scan,
                   int SparcAdjust, struct supertype *forcest, char *homehost);
extern int Monitor(struct mddev_dev *devlist,
                   char *mailaddr, char *alert_cmd,
                   int period, int daemonise, int scan, int oneshot,
                   int dosyslog, int test, char *pidfile, int increments);

extern int Kill(char *dev, struct supertype *st, int force, int quiet, int noexcl);
extern int Kill_subarray(char *dev, char *subarray, int quiet);
extern int Update_subarray(char *dev, char *subarray, char *update, struct mddev_ident *ident, int quiet);
extern int Wait(char *dev);
extern int WaitClean(char *dev, int sock, int verbose);

extern int Incremental(char *devname, int verbose, int runstop,
                       struct supertype *st, char *homehost, int require_homehost,
                       int autof);
extern void RebuildMap(void);
extern int IncrementalScan(int verbose);
extern int IncrementalRemove(char *devname, char *path, int verbose);
extern int CreateBitmap(char *filename, int force, char uuid[16],
                        unsigned long chunksize, unsigned long daemon_sleep,
                        unsigned long write_behind,
                        unsigned long long array_size,
                        int major);
extern int ExamineBitmap(char *filename, int brief, struct supertype *st);
extern int bitmap_update_uuid(int fd, int *uuid, int swap);
extern unsigned long bitmap_sectors(struct bitmap_super_s *bsb);

extern int md_get_version(int fd);
extern int get_linux_version(void);
extern long long parse_size(char *size);
extern int parse_uuid(char *str, int uuid[4]);
extern int parse_layout_10(char *layout);
extern int parse_layout_faulty(char *layout);
extern int check_ext2(int fd, char *name);
extern int check_reiser(int fd, char *name);
extern int check_raid(int fd, char *name);
extern int check_partitions(int fd, char *dname, unsigned long long freesize);

extern int get_mdp_major(void);
extern int dev_open(char *dev, int flags);
extern int open_dev(int devnum);
extern int open_dev_excl(int devnum);
extern int is_standard(char *dev, int *nump);
extern int same_dev(char *one, char *two);

extern int parse_auto(char *str, char *msg, int config);
extern struct mddev_ident *conf_get_ident(char *dev);
extern struct mddev_dev *conf_get_devs(void);
extern int conf_test_dev(char *devname);
extern int conf_test_metadata(const char *version, struct dev_policy *pol, int is_homehost);
extern struct createinfo *conf_get_create_info(void);
extern void set_conffile(char *file);
extern char *conf_get_mailaddr(void);
extern char *conf_get_mailfrom(void);
extern char *conf_get_program(void);
extern char *conf_get_homehost(int *require_homehostp);
extern char *conf_line(FILE *file);
extern char *conf_word(FILE *file, int allow_key);
extern int conf_name_is_free(char *name);
extern int devname_matches(char *name, char *match);
extern struct mddev_ident *conf_match(struct mdinfo *info, struct supertype *st);

extern void free_line(char *line);
extern int match_oneof(char *devices, char *devname);
extern void uuid_from_super(int uuid[4], mdp_super_t *super);
extern const int uuid_match_any[4];
extern int same_uuid(int a[4], int b[4], int swapuuid);
extern void copy_uuid(void *a, int b[4], int swapuuid);
extern char *__fname_from_uuid(int id[4], int swap, char *buf, char sep);
extern char *fname_from_uuid(struct supertype *st,
                             struct mdinfo *info, char *buf, char sep);
extern unsigned long calc_csum(void *super, int bytes);
extern int enough(int level, int raid_disks, int layout, int clean,
                   char *avail, int avail_disks);
extern int enough_fd(int fd);
extern int ask(char *mesg);
extern unsigned long long get_component_size(int fd);
extern void remove_partitions(int fd);
extern int test_partition(int fd);
extern unsigned long long calc_array_size(int level, int raid_disks, int layout,
                                   int chunksize, unsigned long long devsize);
extern int flush_metadata_updates(struct supertype *st);
extern void append_metadata_update(struct supertype *st, void *buf, int len);
extern int assemble_container_content(struct supertype *st, int mdfd,
                                      struct mdinfo *content, int runstop,
                                      char *chosen_name, int verbose);

extern int add_disk(int mdfd, struct supertype *st,
                    struct mdinfo *sra, struct mdinfo *info);
extern int set_array_info(int mdfd, struct supertype *st, struct mdinfo *info);
unsigned long long min_recovery_start(struct mdinfo *array);

extern char *human_size(long long bytes);
extern char *human_size_brief(long long bytes);
extern void print_r10_layout(int layout);

#define NoMdDev (1<<23)
extern int find_free_devnum(int use_partitions);

extern void put_md_name(char *name);
extern char *get_md_name(int dev);

extern char DefaultConfFile[];

extern int create_mddev(char *dev, char *name, int autof, int trustworthy,
                        char *chosen);
/* values for 'trustworthy' */
#define LOCAL   1
#define LOCAL_ANY 10
#define FOREIGN 2
#define METADATA 3
extern int open_mddev(char *dev, int report_errors);
extern int open_container(int fd);
extern int is_container_member(struct mdstat_ent *ent, char *devname);
extern int is_subarray_active(char *subarray, char *devname);
int is_container_active(char *devname);
extern int open_subarray(char *dev, char *subarray, struct supertype *st, int quiet);
extern struct superswitch *version_to_superswitch(char *vers);

extern int mdmon_running(int devnum);
extern int mdmon_pid(int devnum);
extern int check_env(char *name);
extern __u32 random32(void);
extern int start_mdmon(int devnum);

extern char *devnum2devname(int num);
extern int devname2devnum(char *name);
extern int stat2devnum(struct stat *st);
extern int fd2devnum(int fd);

static inline int dev2major(int d)
{
        if (d >= 0)
                return MD_MAJOR;
        else
                return get_mdp_major();
}

static inline int dev2minor(int d)
{
        if (d >= 0)
                return d;
        return (-1-d) << MdpMinorShift;
}

static inline int ROUND_UP(int a, int base)
{
        return ((a+base-1)/base)*base;
}

static inline int is_subarray(char *vers)
{
        /* The version string for a 'subarray' (an array in a container)
         * is 
         *    /containername/componentname    for normal read-write arrays
         *    -containername/componentname    for read-only arrays.
         * containername is e.g. md0, md_d1
         * componentname is dependant on the metadata. e.g. '1' 'S1' ...
         */
        return (*vers == '/' || *vers == '-');
}

#ifdef DEBUG
#define dprintf(fmt, arg...) \
        fprintf(stderr, fmt, ##arg)
#else
#define dprintf(fmt, arg...) \
        ({ if (0) fprintf(stderr, fmt, ##arg); 0; })
#endif
#include <assert.h>
#include <stdarg.h>
static inline int xasprintf(char **strp, const char *fmt, ...) {
        va_list ap;
        int ret;
        va_start(ap, fmt);
        ret = vasprintf(strp, fmt, ap);
        va_end(ap);
        assert(ret >= 0);
        return ret;
}

#define LEVEL_MULTIPATH         (-4)
#define LEVEL_LINEAR            (-1)
#define LEVEL_FAULTY            (-5)

/* kernel module doesn't know about these */
#define LEVEL_CONTAINER         (-100)
#define LEVEL_UNSUPPORTED       (-200)


/* faulty stuff */

#define WriteTransient  0
#define ReadTransient   1
#define WritePersistent 2
#define ReadPersistent  3
#define WriteAll        4 /* doesn't go to device */
#define ReadFixable     5
#define Modes   6

#define ClearErrors     31
#define ClearFaults     30

#define AllPersist      100 /* internal use only */
#define NoPersist       101

#define ModeMask        0x1f
#define ModeShift       5


#ifdef __TINYC__
#undef minor
#undef major
#undef makedev
#define minor(x) ((x)&0xff)
#define major(x) (((x)>>8)&0xff)
#define makedev(M,m) (((M)<<8) | (m))
#endif

/* for raid4/5/6 */
#define ALGORITHM_LEFT_ASYMMETRIC       0
#define ALGORITHM_RIGHT_ASYMMETRIC      1
#define ALGORITHM_LEFT_SYMMETRIC        2
#define ALGORITHM_RIGHT_SYMMETRIC       3

/* Define non-rotating (raid4) algorithms.  These allow
 * conversion of raid4 to raid5.
 */
#define ALGORITHM_PARITY_0              4 /* P or P,Q are initial devices */
#define ALGORITHM_PARITY_N              5 /* P or P,Q are final devices. */

/* DDF RAID6 layouts differ from md/raid6 layouts in two ways.
 * Firstly, the exact positioning of the parity block is slightly
 * different between the 'LEFT_*' modes of md and the "_N_*" modes
 * of DDF.
 * Secondly, or order of datablocks over which the Q syndrome is computed
 * is different.
 * Consequently we have different layouts for DDF/raid6 than md/raid6.
 * These layouts are from the DDFv1.2 spec.
 * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but
 * leaves RLQ=3 as 'Vendor Specific'
 */

#define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */
#define ALGORITHM_ROTATING_N_RESTART    9 /* DDF PRL=6 RLQ=2 */
#define ALGORITHM_ROTATING_N_CONTINUE   10 /*DDF PRL=6 RLQ=3 */


/* For every RAID5 algorithm we define a RAID6 algorithm
 * with exactly the same layout for data and parity, and
 * with the Q block always on the last device (N-1).
 * This allows trivial conversion from RAID5 to RAID6
 */
#define ALGORITHM_LEFT_ASYMMETRIC_6     16
#define ALGORITHM_RIGHT_ASYMMETRIC_6    17
#define ALGORITHM_LEFT_SYMMETRIC_6      18
#define ALGORITHM_RIGHT_SYMMETRIC_6     19
#define ALGORITHM_PARITY_0_6            20
#define ALGORITHM_PARITY_N_6            ALGORITHM_PARITY_N

/* Define PATH_MAX in case we don't use glibc or standard library does
 * not have PATH_MAX defined. Assume max path length is 4K characters.
 */
#ifndef PATH_MAX
#define PATH_MAX        4096
#endif