Ricardo Labiaga | 85e174b | 2010-10-20 00:17:58 -0400 | [diff] [blame] | 1 | /* |
| 2 | * pNFS functions to call and manage layout drivers. |
| 3 | * |
| 4 | * Copyright (c) 2002 [year of first publication] |
| 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 | #include <linux/nfs_fs.h> |
| 31 | #include "pnfs.h" |
| 32 | |
| 33 | #define NFSDBG_FACILITY NFSDBG_PNFS |
| 34 | |
Fred Isaman | 02c35fc | 2010-10-20 00:17:59 -0400 | [diff] [blame] | 35 | /* Locking: |
| 36 | * |
| 37 | * pnfs_spinlock: |
| 38 | * protects pnfs_modules_tbl. |
| 39 | */ |
| 40 | static DEFINE_SPINLOCK(pnfs_spinlock); |
| 41 | |
| 42 | /* |
| 43 | * pnfs_modules_tbl holds all pnfs modules |
| 44 | */ |
| 45 | static LIST_HEAD(pnfs_modules_tbl); |
| 46 | |
| 47 | /* Return the registered pnfs layout driver module matching given id */ |
| 48 | static struct pnfs_layoutdriver_type * |
| 49 | find_pnfs_driver_locked(u32 id) |
| 50 | { |
| 51 | struct pnfs_layoutdriver_type *local; |
| 52 | |
| 53 | list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid) |
| 54 | if (local->id == id) |
| 55 | goto out; |
| 56 | local = NULL; |
| 57 | out: |
| 58 | dprintk("%s: Searching for id %u, found %p\n", __func__, id, local); |
| 59 | return local; |
| 60 | } |
| 61 | |
Ricardo Labiaga | 85e174b | 2010-10-20 00:17:58 -0400 | [diff] [blame] | 62 | static struct pnfs_layoutdriver_type * |
| 63 | find_pnfs_driver(u32 id) |
| 64 | { |
Fred Isaman | 02c35fc | 2010-10-20 00:17:59 -0400 | [diff] [blame] | 65 | struct pnfs_layoutdriver_type *local; |
| 66 | |
| 67 | spin_lock(&pnfs_spinlock); |
| 68 | local = find_pnfs_driver_locked(id); |
| 69 | spin_unlock(&pnfs_spinlock); |
| 70 | return local; |
Ricardo Labiaga | 85e174b | 2010-10-20 00:17:58 -0400 | [diff] [blame] | 71 | } |
| 72 | |
| 73 | void |
| 74 | unset_pnfs_layoutdriver(struct nfs_server *nfss) |
| 75 | { |
Fred Isaman | 02c35fc | 2010-10-20 00:17:59 -0400 | [diff] [blame] | 76 | if (nfss->pnfs_curr_ld) { |
| 77 | nfss->pnfs_curr_ld->uninitialize_mountpoint(nfss); |
| 78 | module_put(nfss->pnfs_curr_ld->owner); |
| 79 | } |
Ricardo Labiaga | 85e174b | 2010-10-20 00:17:58 -0400 | [diff] [blame] | 80 | nfss->pnfs_curr_ld = NULL; |
| 81 | } |
| 82 | |
| 83 | /* |
| 84 | * Try to set the server's pnfs module to the pnfs layout type specified by id. |
| 85 | * Currently only one pNFS layout driver per filesystem is supported. |
| 86 | * |
| 87 | * @id layout type. Zero (illegal layout type) indicates pNFS not in use. |
| 88 | */ |
| 89 | void |
| 90 | set_pnfs_layoutdriver(struct nfs_server *server, u32 id) |
| 91 | { |
| 92 | struct pnfs_layoutdriver_type *ld_type = NULL; |
| 93 | |
| 94 | if (id == 0) |
| 95 | goto out_no_driver; |
| 96 | if (!(server->nfs_client->cl_exchange_flags & |
| 97 | (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) { |
| 98 | printk(KERN_ERR "%s: id %u cl_exchange_flags 0x%x\n", __func__, |
| 99 | id, server->nfs_client->cl_exchange_flags); |
| 100 | goto out_no_driver; |
| 101 | } |
| 102 | ld_type = find_pnfs_driver(id); |
| 103 | if (!ld_type) { |
| 104 | request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id); |
| 105 | ld_type = find_pnfs_driver(id); |
| 106 | if (!ld_type) { |
| 107 | dprintk("%s: No pNFS module found for %u.\n", |
| 108 | __func__, id); |
| 109 | goto out_no_driver; |
| 110 | } |
| 111 | } |
Fred Isaman | 02c35fc | 2010-10-20 00:17:59 -0400 | [diff] [blame] | 112 | if (!try_module_get(ld_type->owner)) { |
| 113 | dprintk("%s: Could not grab reference on module\n", __func__); |
| 114 | goto out_no_driver; |
| 115 | } |
Ricardo Labiaga | 85e174b | 2010-10-20 00:17:58 -0400 | [diff] [blame] | 116 | server->pnfs_curr_ld = ld_type; |
Fred Isaman | 02c35fc | 2010-10-20 00:17:59 -0400 | [diff] [blame] | 117 | if (ld_type->initialize_mountpoint(server)) { |
| 118 | printk(KERN_ERR |
| 119 | "%s: Error initializing mount point for layout driver %u.\n", |
| 120 | __func__, id); |
| 121 | module_put(ld_type->owner); |
| 122 | goto out_no_driver; |
| 123 | } |
Ricardo Labiaga | 85e174b | 2010-10-20 00:17:58 -0400 | [diff] [blame] | 124 | dprintk("%s: pNFS module for %u set\n", __func__, id); |
| 125 | return; |
| 126 | |
| 127 | out_no_driver: |
| 128 | dprintk("%s: Using NFSv4 I/O\n", __func__); |
| 129 | server->pnfs_curr_ld = NULL; |
| 130 | } |
Fred Isaman | 02c35fc | 2010-10-20 00:17:59 -0400 | [diff] [blame] | 131 | |
| 132 | int |
| 133 | pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type) |
| 134 | { |
| 135 | int status = -EINVAL; |
| 136 | struct pnfs_layoutdriver_type *tmp; |
| 137 | |
| 138 | if (ld_type->id == 0) { |
| 139 | printk(KERN_ERR "%s id 0 is reserved\n", __func__); |
| 140 | return status; |
| 141 | } |
| 142 | |
| 143 | spin_lock(&pnfs_spinlock); |
| 144 | tmp = find_pnfs_driver_locked(ld_type->id); |
| 145 | if (!tmp) { |
| 146 | list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl); |
| 147 | status = 0; |
| 148 | dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id, |
| 149 | ld_type->name); |
| 150 | } else { |
| 151 | printk(KERN_ERR "%s Module with id %d already loaded!\n", |
| 152 | __func__, ld_type->id); |
| 153 | } |
| 154 | spin_unlock(&pnfs_spinlock); |
| 155 | |
| 156 | return status; |
| 157 | } |
| 158 | EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver); |
| 159 | |
| 160 | void |
| 161 | pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type) |
| 162 | { |
| 163 | dprintk("%s Deregistering id:%u\n", __func__, ld_type->id); |
| 164 | spin_lock(&pnfs_spinlock); |
| 165 | list_del(&ld_type->pnfs_tblid); |
| 166 | spin_unlock(&pnfs_spinlock); |
| 167 | } |
| 168 | EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver); |
Benny Halevy | e5e9401 | 2010-10-20 00:18:01 -0400 | [diff] [blame^] | 169 | |
| 170 | static void |
| 171 | get_layout_hdr_locked(struct pnfs_layout_hdr *lo) |
| 172 | { |
| 173 | assert_spin_locked(&lo->inode->i_lock); |
| 174 | lo->refcount++; |
| 175 | } |
| 176 | |
| 177 | static void |
| 178 | put_layout_hdr_locked(struct pnfs_layout_hdr *lo) |
| 179 | { |
| 180 | assert_spin_locked(&lo->inode->i_lock); |
| 181 | BUG_ON(lo->refcount == 0); |
| 182 | |
| 183 | lo->refcount--; |
| 184 | if (!lo->refcount) { |
| 185 | dprintk("%s: freeing layout cache %p\n", __func__, lo); |
| 186 | NFS_I(lo->inode)->layout = NULL; |
| 187 | kfree(lo); |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | void |
| 192 | pnfs_destroy_layout(struct nfs_inode *nfsi) |
| 193 | { |
| 194 | struct pnfs_layout_hdr *lo; |
| 195 | |
| 196 | spin_lock(&nfsi->vfs_inode.i_lock); |
| 197 | lo = nfsi->layout; |
| 198 | if (lo) { |
| 199 | /* Matched by refcount set to 1 in alloc_init_layout_hdr */ |
| 200 | put_layout_hdr_locked(lo); |
| 201 | } |
| 202 | spin_unlock(&nfsi->vfs_inode.i_lock); |
| 203 | } |
| 204 | |
| 205 | /* STUB - pretend LAYOUTGET to server failed */ |
| 206 | static struct pnfs_layout_segment * |
| 207 | send_layoutget(struct pnfs_layout_hdr *lo, |
| 208 | struct nfs_open_context *ctx, |
| 209 | u32 iomode) |
| 210 | { |
| 211 | struct inode *ino = lo->inode; |
| 212 | |
| 213 | set_bit(lo_fail_bit(iomode), &lo->state); |
| 214 | spin_lock(&ino->i_lock); |
| 215 | put_layout_hdr_locked(lo); |
| 216 | spin_unlock(&ino->i_lock); |
| 217 | return NULL; |
| 218 | } |
| 219 | |
| 220 | static struct pnfs_layout_hdr * |
| 221 | alloc_init_layout_hdr(struct inode *ino) |
| 222 | { |
| 223 | struct pnfs_layout_hdr *lo; |
| 224 | |
| 225 | lo = kzalloc(sizeof(struct pnfs_layout_hdr), GFP_KERNEL); |
| 226 | if (!lo) |
| 227 | return NULL; |
| 228 | lo->refcount = 1; |
| 229 | lo->inode = ino; |
| 230 | return lo; |
| 231 | } |
| 232 | |
| 233 | static struct pnfs_layout_hdr * |
| 234 | pnfs_find_alloc_layout(struct inode *ino) |
| 235 | { |
| 236 | struct nfs_inode *nfsi = NFS_I(ino); |
| 237 | struct pnfs_layout_hdr *new = NULL; |
| 238 | |
| 239 | dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout); |
| 240 | |
| 241 | assert_spin_locked(&ino->i_lock); |
| 242 | if (nfsi->layout) |
| 243 | return nfsi->layout; |
| 244 | |
| 245 | spin_unlock(&ino->i_lock); |
| 246 | new = alloc_init_layout_hdr(ino); |
| 247 | spin_lock(&ino->i_lock); |
| 248 | |
| 249 | if (likely(nfsi->layout == NULL)) /* Won the race? */ |
| 250 | nfsi->layout = new; |
| 251 | else |
| 252 | kfree(new); |
| 253 | return nfsi->layout; |
| 254 | } |
| 255 | |
| 256 | /* STUB - LAYOUTGET never succeeds, so cache is empty */ |
| 257 | static struct pnfs_layout_segment * |
| 258 | pnfs_has_layout(struct pnfs_layout_hdr *lo, u32 iomode) |
| 259 | { |
| 260 | return NULL; |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * Layout segment is retreived from the server if not cached. |
| 265 | * The appropriate layout segment is referenced and returned to the caller. |
| 266 | */ |
| 267 | struct pnfs_layout_segment * |
| 268 | pnfs_update_layout(struct inode *ino, |
| 269 | struct nfs_open_context *ctx, |
| 270 | enum pnfs_iomode iomode) |
| 271 | { |
| 272 | struct nfs_inode *nfsi = NFS_I(ino); |
| 273 | struct pnfs_layout_hdr *lo; |
| 274 | struct pnfs_layout_segment *lseg = NULL; |
| 275 | |
| 276 | if (!pnfs_enabled_sb(NFS_SERVER(ino))) |
| 277 | return NULL; |
| 278 | spin_lock(&ino->i_lock); |
| 279 | lo = pnfs_find_alloc_layout(ino); |
| 280 | if (lo == NULL) { |
| 281 | dprintk("%s ERROR: can't get pnfs_layout_hdr\n", __func__); |
| 282 | goto out_unlock; |
| 283 | } |
| 284 | |
| 285 | /* Check to see if the layout for the given range already exists */ |
| 286 | lseg = pnfs_has_layout(lo, iomode); |
| 287 | if (lseg) { |
| 288 | dprintk("%s: Using cached lseg %p for iomode %d)\n", |
| 289 | __func__, lseg, iomode); |
| 290 | goto out_unlock; |
| 291 | } |
| 292 | |
| 293 | /* if LAYOUTGET already failed once we don't try again */ |
| 294 | if (test_bit(lo_fail_bit(iomode), &nfsi->layout->state)) |
| 295 | goto out_unlock; |
| 296 | |
| 297 | get_layout_hdr_locked(lo); |
| 298 | spin_unlock(&ino->i_lock); |
| 299 | |
| 300 | lseg = send_layoutget(lo, ctx, iomode); |
| 301 | out: |
| 302 | dprintk("%s end, state 0x%lx lseg %p\n", __func__, |
| 303 | nfsi->layout->state, lseg); |
| 304 | return lseg; |
| 305 | out_unlock: |
| 306 | spin_unlock(&ino->i_lock); |
| 307 | goto out; |
| 308 | } |