blocklayout.h

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/*
 *  linux/fs/nfs/blocklayout/blocklayout.h
 *
 *  Module for the NFSv4.1 pNFS block layout driver.
 *
 *  Copyright (c) 2006 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Andy Adamson <[email protected]>
 *  Fred Isaman <[email protected]>
 *
 * permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any purpose,
 * so long as the name of the university of michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.  if
 * the above copyright notice or any other identification of the
 * university of michigan is included in any copy of any portion of
 * this software, then the disclaimer below must also be included.
 *
 * this software is provided as is, without representation from the
 * university of michigan as to its fitness for any purpose, and without
 * warranty by the university of michigan of any kind, either express
 * or implied, including without limitation the implied warranties of
 * merchantability and fitness for a particular purpose.  the regents
 * of the university of michigan shall not be liable for any damages,
 * including special, indirect, incidental, or consequential damages,
 * with respect to any claim arising out or in connection with the use
 * of the software, even if it has been or is hereafter advised of the
 * possibility of such damages.
 */
#ifndef FS_NFS_NFS4BLOCKLAYOUT_H
#define FS_NFS_NFS4BLOCKLAYOUT_H

#include <linux/device-mapper.h>
#include <linux/nfs_fs.h>
#include <linux/sunrpc/rpc_pipe_fs.h>

#include "../pnfs.h"
#include "../netns.h"

#define PAGE_CACHE_SECTORS (PAGE_CACHE_SIZE >> SECTOR_SHIFT)
#define PAGE_CACHE_SECTOR_SHIFT (PAGE_CACHE_SHIFT - SECTOR_SHIFT)
#define SECTOR_SIZE (1 << SECTOR_SHIFT)

struct block_mount_id {
    spinlock_t          bm_lock;    /* protects list */
    struct list_head        bm_devlist; /* holds pnfs_block_dev */
};

struct pnfs_block_dev {
    struct list_head        bm_node;
    struct nfs4_deviceid        bm_mdevid;    /* associated devid */
    struct block_device     *bm_mdev;     /* meta device itself */
    struct net          *net;
};

enum exstate4 {
    PNFS_BLOCK_READWRITE_DATA   = 0,
    PNFS_BLOCK_READ_DATA        = 1,
    PNFS_BLOCK_INVALID_DATA     = 2, /* mapped, but data is invalid */
    PNFS_BLOCK_NONE_DATA        = 3  /* unmapped, it's a hole */
};

#define MY_MAX_TAGS (15) /* tag bitnums used must be less than this */

struct my_tree {
    sector_t        mtt_step_size;  /* Internal sector alignment */
    struct list_head    mtt_stub; /* Should be a radix tree */
};

struct pnfs_inval_markings {
    spinlock_t  im_lock;
    struct my_tree  im_tree;    /* Sectors that need LAYOUTCOMMIT */
    sector_t    im_block_size;  /* Server blocksize in sectors */
    struct list_head im_extents;    /* Short extents for INVAL->RW conversion */
};

struct pnfs_inval_tracking {
    struct list_head it_link;
    int      it_sector;
    int      it_tags;
};

/* sector_t fields are all in 512-byte sectors */
struct pnfs_block_extent {
    struct kref be_refcnt;
    struct list_head be_node;   /* link into lseg list */
    struct nfs4_deviceid be_devid;  /* FIXME: could use device cache instead */
    struct block_device *be_mdev;
    sector_t    be_f_offset;    /* the starting offset in the file */
    sector_t    be_length;  /* the size of the extent */
    sector_t    be_v_offset;    /* the starting offset in the volume */
    enum exstate4   be_state;   /* the state of this extent */
    struct pnfs_inval_markings *be_inval; /* tracks INVAL->RW transition */
};

/* Shortened extent used by LAYOUTCOMMIT */
struct pnfs_block_short_extent {
    struct list_head bse_node;
    struct nfs4_deviceid bse_devid;
    struct block_device *bse_mdev;
    sector_t    bse_f_offset;   /* the starting offset in the file */
    sector_t    bse_length; /* the size of the extent */
};

static inline void
BL_INIT_INVAL_MARKS(struct pnfs_inval_markings *marks, sector_t blocksize)
{
    spin_lock_init(&marks->im_lock);
    INIT_LIST_HEAD(&marks->im_tree.mtt_stub);
    INIT_LIST_HEAD(&marks->im_extents);
    marks->im_block_size = blocksize;
    marks->im_tree.mtt_step_size = min((sector_t)PAGE_CACHE_SECTORS,
                       blocksize);
}

enum extentclass4 {
    RW_EXTENT       = 0, /* READWRTE and INVAL */
    RO_EXTENT       = 1, /* READ and NONE */
    EXTENT_LISTS    = 2,
};

static inline int bl_choose_list(enum exstate4 state)
{
    if (state == PNFS_BLOCK_READ_DATA || state == PNFS_BLOCK_NONE_DATA)
        return RO_EXTENT;
    else
        return RW_EXTENT;
}

struct pnfs_block_layout {
    struct pnfs_layout_hdr bl_layout;
    struct pnfs_inval_markings bl_inval; /* tracks INVAL->RW transition */
    spinlock_t      bl_ext_lock;   /* Protects list manipulation */
    struct list_head    bl_extents[EXTENT_LISTS]; /* R and RW extents */
    struct list_head    bl_commit;  /* Needs layout commit */
    struct list_head    bl_committing;  /* Layout committing */
    unsigned int        bl_count;   /* entries in bl_commit */
    sector_t        bl_blocksize;  /* Server blocksize in sectors */
};

#define BLK_ID(lo) ((struct block_mount_id *)(NFS_SERVER(lo->plh_inode)->pnfs_ld_data))

static inline struct pnfs_block_layout *
BLK_LO2EXT(struct pnfs_layout_hdr *lo)
{
    return container_of(lo, struct pnfs_block_layout, bl_layout);
}

static inline struct pnfs_block_layout *
BLK_LSEG2EXT(struct pnfs_layout_segment *lseg)
{
    return BLK_LO2EXT(lseg->pls_layout);
}

struct bl_pipe_msg {
    struct rpc_pipe_msg msg;
    wait_queue_head_t *bl_wq;
};

struct bl_msg_hdr {
    u8  type;
    u16 totallen; /* length of entire message, including hdr itself */
};

#define BL_DEVICE_UMOUNT               0x0 /* Umount--delete devices */
#define BL_DEVICE_MOUNT                0x1 /* Mount--create devices*/
#define BL_DEVICE_REQUEST_INIT         0x0 /* Start request */
#define BL_DEVICE_REQUEST_PROC         0x1 /* User level process succeeds */
#define BL_DEVICE_REQUEST_ERR          0x2 /* User level process fails */

/* blocklayoutdev.c */
ssize_t bl_pipe_downcall(struct file *, const char __user *, size_t);
void bl_pipe_destroy_msg(struct rpc_pipe_msg *);
int nfs4_blkdev_put(struct block_device *bdev);
struct pnfs_block_dev *nfs4_blk_decode_device(struct nfs_server *server,
                        struct pnfs_device *dev);
int nfs4_blk_process_layoutget(struct pnfs_layout_hdr *lo,
                struct nfs4_layoutget_res *lgr, gfp_t gfp_flags);

/* blocklayoutdm.c */
void bl_free_block_dev(struct pnfs_block_dev *bdev);

/* extents.c */
struct pnfs_block_extent *
bl_find_get_extent(struct pnfs_block_layout *bl, sector_t isect,
        struct pnfs_block_extent **cow_read);
int bl_mark_sectors_init(struct pnfs_inval_markings *marks,
                 sector_t offset, sector_t length);
void bl_put_extent(struct pnfs_block_extent *be);
struct pnfs_block_extent *bl_alloc_extent(void);
int bl_is_sector_init(struct pnfs_inval_markings *marks, sector_t isect);
int encode_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
                   struct xdr_stream *xdr,
                   const struct nfs4_layoutcommit_args *arg);
void clean_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
                   const struct nfs4_layoutcommit_args *arg,
                   int status);
int bl_add_merge_extent(struct pnfs_block_layout *bl,
             struct pnfs_block_extent *new);
int bl_mark_for_commit(struct pnfs_block_extent *be,
            sector_t offset, sector_t length,
            struct pnfs_block_short_extent *new);
int bl_push_one_short_extent(struct pnfs_inval_markings *marks);
struct pnfs_block_short_extent *
bl_pop_one_short_extent(struct pnfs_inval_markings *marks);
void bl_free_short_extents(struct pnfs_inval_markings *marks, int num_to_free);

#endif /* FS_NFS_NFS4BLOCKLAYOUT_H */