fs/nfs/pnfs.h

   1 /*
   2  *  pNFS client data structures.
   3  *
   4  *  Copyright (c) 2002
   5  *  The Regents of the University of Michigan
   6  *  All Rights Reserved
   7  *
   8  *  Dean Hildebrand <dhildebz@umich.edu>
   9  *
  10  *  Permission is granted to use, copy, create derivative works, and
  11  *  redistribute this software and such derivative works for any purpose,
  12  *  so long as the name of the University of Michigan is not used in
  13  *  any advertising or publicity pertaining to the use or distribution
  14  *  of this software without specific, written prior authorization. If
  15  *  the above copyright notice or any other identification of the
  16  *  University of Michigan is included in any copy of any portion of
  17  *  this software, then the disclaimer below must also be included.
  18  *
  19  *  This software is provided as is, without representation or warranty
  20  *  of any kind either express or implied, including without limitation
  21  *  the implied warranties of merchantability, fitness for a particular
  22  *  purpose, or noninfringement.  The Regents of the University of
  23  *  Michigan shall not be liable for any damages, including special,
  24  *  indirect, incidental, or consequential damages, with respect to any
  25  *  claim arising out of or in connection with the use of the software,
  26  *  even if it has been or is hereafter advised of the possibility of
  27  *  such damages.
  28  */
  29
  30 #ifndef FS_NFS_PNFS_H
  31 #define FS_NFS_PNFS_H
  32
  33 struct pnfs_layout_segment {
  34         struct list_head fi_list;
  35         struct pnfs_layout_range range;
  36         struct kref kref;
  37         struct pnfs_layout_hdr *layout;
  38 };
  39
  40 #ifdef CONFIG_NFS_V4_1
  41
  42 #define LAYOUT_NFSV4_1_MODULE_PREFIX "nfs-layouttype4"
  43
  44 enum {
  45         NFS_LAYOUT_RO_FAILED = 0,       /* get ro layout failed stop trying */
  46         NFS_LAYOUT_RW_FAILED,           /* get rw layout failed stop trying */
  47         NFS_LAYOUT_STATEID_SET,         /* have a valid layout stateid */
  48 };
  49
  50 /* Per-layout driver specific registration structure */
  51 struct pnfs_layoutdriver_type {
  52         struct list_head pnfs_tblid;
  53         const u32 id;
  54         const char *name;
  55         struct module *owner;
  56         int (*set_layoutdriver) (struct nfs_server *);
  57         int (*clear_layoutdriver) (struct nfs_server *);
  58         struct pnfs_layout_segment * (*alloc_lseg) (struct pnfs_layout_hdr *layoutid, struct nfs4_layoutget_res *lgr);
  59         void (*free_lseg) (struct pnfs_layout_segment *lseg);
  60 };
  61
  62 struct pnfs_layout_hdr {
  63         unsigned long           refcount;
  64         struct list_head        layouts;   /* other client layouts */
  65         struct list_head        segs;      /* layout segments list */
  66         seqlock_t               seqlock;   /* Protects the stateid */
  67         nfs4_stateid            stateid;
  68         unsigned long           state;
  69         struct inode            *inode;
  70 };
  71
  72 struct pnfs_device {
  73         struct nfs4_deviceid dev_id;
  74         unsigned int  layout_type;
  75         unsigned int  mincount;
  76         struct page **pages;
  77         void          *area;
  78         unsigned int  pgbase;
  79         unsigned int  pglen;
  80 };
  81
  82 /*
  83  * Device ID RCU cache. A device ID is unique per client ID and layout type.
  84  */
  85 #define NFS4_DEVICE_ID_HASH_BITS        5
  86 #define NFS4_DEVICE_ID_HASH_SIZE        (1 << NFS4_DEVICE_ID_HASH_BITS)
  87 #define NFS4_DEVICE_ID_HASH_MASK        (NFS4_DEVICE_ID_HASH_SIZE - 1)
  88
  89 static inline u32
  90 nfs4_deviceid_hash(struct nfs4_deviceid *id)
  91 {
  92         unsigned char *cptr = (unsigned char *)id->data;
  93         unsigned int nbytes = NFS4_DEVICEID4_SIZE;
  94         u32 x = 0;
  95
  96         while (nbytes--) {
  97                 x *= 37;
  98                 x += *cptr++;
  99         }
 100         return x & NFS4_DEVICE_ID_HASH_MASK;
 101 }
 102
 103 struct pnfs_deviceid_node {
 104         struct hlist_node       de_node;
 105         struct nfs4_deviceid    de_id;
 106         atomic_t                de_ref;
 107 };
 108
 109 struct pnfs_deviceid_cache {
 110         spinlock_t              dc_lock;
 111         atomic_t                dc_ref;
 112         void                    (*dc_free_callback)(struct pnfs_deviceid_node *);
 113         struct hlist_head       dc_deviceids[NFS4_DEVICE_ID_HASH_SIZE];
 114 };
 115
 116 extern int pnfs_alloc_init_deviceid_cache(struct nfs_client *,
 117                         void (*free_callback)(struct pnfs_deviceid_node *));
 118 extern void pnfs_put_deviceid_cache(struct nfs_client *);
 119 extern struct pnfs_deviceid_node *pnfs_find_get_deviceid(
 120                                 struct pnfs_deviceid_cache *,
 121                                 struct nfs4_deviceid *);
 122 extern struct pnfs_deviceid_node *pnfs_add_deviceid(
 123                                 struct pnfs_deviceid_cache *,
 124                                 struct pnfs_deviceid_node *);
 125 extern void pnfs_put_deviceid(struct pnfs_deviceid_cache *c,
 126                               struct pnfs_deviceid_node *devid);
 127
 128 extern int pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *);
 129 extern void pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *);
 130
 131 /* nfs4proc.c */
 132 extern int nfs4_proc_getdeviceinfo(struct nfs_server *server,
 133                                    struct pnfs_device *dev);
 134 extern int nfs4_proc_layoutget(struct nfs4_layoutget *lgp);
 135
 136 /* pnfs.c */
 137 struct pnfs_layout_segment *
 138 pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,
 139                    enum pnfs_iomode access_type);
 140 void set_pnfs_layoutdriver(struct nfs_server *, u32 id);
 141 void unset_pnfs_layoutdriver(struct nfs_server *);
 142 int pnfs_layout_process(struct nfs4_layoutget *lgp);
 143 void pnfs_destroy_layout(struct nfs_inode *);
 144 void pnfs_destroy_all_layouts(struct nfs_client *);
 145 void put_layout_hdr(struct inode *inode);
 146 void pnfs_get_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
 147                              struct nfs4_state *open_state);
 148
 149
 150 static inline int lo_fail_bit(u32 iomode)
 151 {
 152         return iomode == IOMODE_RW ?
 153                          NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
 154 }
 155
 156 /* Return true if a layout driver is being used for this mountpoint */
 157 static inline int pnfs_enabled_sb(struct nfs_server *nfss)
 158 {
 159         return nfss->pnfs_curr_ld != NULL;
 160 }
 161
 162 #else  /* CONFIG_NFS_V4_1 */
 163
 164 static inline void pnfs_destroy_all_layouts(struct nfs_client *clp)
 165 {
 166 }
 167
 168 static inline void pnfs_destroy_layout(struct nfs_inode *nfsi)
 169 {
 170 }
 171
 172 static inline struct pnfs_layout_segment *
 173 pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,
 174                    enum pnfs_iomode access_type)
 175 {
 176         return NULL;
 177 }
 178
 179 static inline void set_pnfs_layoutdriver(struct nfs_server *s, u32 id)
 180 {
 181 }
 182
 183 static inline void unset_pnfs_layoutdriver(struct nfs_server *s)
 184 {
 185 }
 186
 187 #endif /* CONFIG_NFS_V4_1 */
 188
 189 #endif /* FS_NFS_PNFS_H */