fs/nfs/blocklayout/blocklayoutdev.c

   1 /*
   2  *  linux/fs/nfs/blocklayout/blocklayoutdev.c
   3  *
   4  *  Device operations for the pnfs nfs4 file layout driver.
   5  *
   6  *  Copyright (c) 2006 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Andy Adamson <andros@citi.umich.edu>
  10  *  Fred Isaman <iisaman@umich.edu>
  11  *
  12  * permission is granted to use, copy, create derivative works and
  13  * redistribute this software and such derivative works for any purpose,
  14  * so long as the name of the university of michigan is not used in
  15  * any advertising or publicity pertaining to the use or distribution
  16  * of this software without specific, written prior authorization.  if
  17  * the above copyright notice or any other identification of the
  18  * university of michigan is included in any copy of any portion of
  19  * this software, then the disclaimer below must also be included.
  20  *
  21  * this software is provided as is, without representation from the
  22  * university of michigan as to its fitness for any purpose, and without
  23  * warranty by the university of michigan of any kind, either express
  24  * or implied, including without limitation the implied warranties of
  25  * merchantability and fitness for a particular purpose.  the regents
  26  * of the university of michigan shall not be liable for any damages,
  27  * including special, indirect, incidental, or consequential damages,
  28  * with respect to any claim arising out or in connection with the use
  29  * of the software, even if it has been or is hereafter advised of the
  30  * possibility of such damages.
  31  */
  32 #include <linux/module.h>
  33 #include <linux/buffer_head.h> /* __bread */
  34
  35 #include <linux/genhd.h>
  36 #include <linux/blkdev.h>
  37 #include <linux/hash.h>
  38
  39 #include "blocklayout.h"
  40
  41 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  42
  43 static int decode_sector_number(__be32 **rp, sector_t *sp)
  44 {
  45         uint64_t s;
  46
  47         *rp = xdr_decode_hyper(*rp, &s);
  48         if (s & 0x1ff) {
  49                 printk(KERN_WARNING "NFS: %s: sector not aligned\n", __func__);
  50                 return -1;
  51         }
  52         *sp = s >> SECTOR_SHIFT;
  53         return 0;
  54 }
  55
  56 /*
  57  * Release the block device
  58  */
  59 int nfs4_blkdev_put(struct block_device *bdev)
  60 {
  61         dprintk("%s for device %d:%d\n", __func__, MAJOR(bdev->bd_dev),
  62                         MINOR(bdev->bd_dev));
  63         return blkdev_put(bdev, FMODE_READ);
  64 }
  65
  66 ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
  67                          size_t mlen)
  68 {
  69         struct nfs_net *nn = net_generic(filp->f_dentry->d_sb->s_fs_info,
  70                                          nfs_net_id);
  71
  72         if (mlen != sizeof (struct bl_dev_msg))
  73                 return -EINVAL;
  74
  75         if (copy_from_user(&nn->bl_mount_reply, src, mlen) != 0)
  76                 return -EFAULT;
  77
  78         wake_up(&nn->bl_wq);
  79
  80         return mlen;
  81 }
  82
  83 void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
  84 {
  85         struct bl_pipe_msg *bl_pipe_msg = container_of(msg, struct bl_pipe_msg, msg);
  86
  87         if (msg->errno >= 0)
  88                 return;
  89         wake_up(bl_pipe_msg->bl_wq);
  90 }
  91
  92 /*
  93  * Decodes pnfs_block_deviceaddr4 which is XDR encoded in dev->dev_addr_buf.
  94  */
  95 struct pnfs_block_dev *
  96 nfs4_blk_decode_device(struct nfs_server *server,
  97                        struct pnfs_device *dev)
  98 {
  99         struct pnfs_block_dev *rv;
 100         struct block_device *bd = NULL;
 101         struct bl_pipe_msg bl_pipe_msg;
 102         struct rpc_pipe_msg *msg = &bl_pipe_msg.msg;
 103         struct bl_msg_hdr bl_msg = {
 104                 .type = BL_DEVICE_MOUNT,
 105                 .totallen = dev->mincount,
 106         };
 107         uint8_t *dataptr;
 108         DECLARE_WAITQUEUE(wq, current);
 109         int offset, len, i, rc;
 110         struct net *net = server->nfs_client->cl_net;
 111         struct nfs_net *nn = net_generic(net, nfs_net_id);
 112         struct bl_dev_msg *reply = &nn->bl_mount_reply;
 113
 114         dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
 115         dprintk("%s: deviceid: %s, mincount: %d\n", __func__, dev->dev_id.data,
 116                 dev->mincount);
 117
 118         bl_pipe_msg.bl_wq = &nn->bl_wq;
 119         memset(msg, 0, sizeof(*msg));
 120         msg->data = kzalloc(sizeof(bl_msg) + dev->mincount, GFP_NOFS);
 121         if (!msg->data) {
 122                 rv = ERR_PTR(-ENOMEM);
 123                 goto out;
 124         }
 125
 126         memcpy(msg->data, &bl_msg, sizeof(bl_msg));
 127         dataptr = (uint8_t *) msg->data;
 128         len = dev->mincount;
 129         offset = sizeof(bl_msg);
 130         for (i = 0; len > 0; i++) {
 131                 memcpy(&dataptr[offset], page_address(dev->pages[i]),
 132                                 len < PAGE_CACHE_SIZE ? len : PAGE_CACHE_SIZE);
 133                 len -= PAGE_CACHE_SIZE;
 134                 offset += PAGE_CACHE_SIZE;
 135         }
 136         msg->len = sizeof(bl_msg) + dev->mincount;
 137
 138         dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
 139         add_wait_queue(&nn->bl_wq, &wq);
 140         rc = rpc_queue_upcall(nn->bl_device_pipe, msg);
 141         if (rc < 0) {
 142                 remove_wait_queue(&nn->bl_wq, &wq);
 143                 rv = ERR_PTR(rc);
 144                 goto out;
 145         }
 146
 147         set_current_state(TASK_UNINTERRUPTIBLE);
 148         schedule();
 149         __set_current_state(TASK_RUNNING);
 150         remove_wait_queue(&nn->bl_wq, &wq);
 151
 152         if (reply->status != BL_DEVICE_REQUEST_PROC) {
 153                 dprintk("%s failed to open device: %d\n",
 154                         __func__, reply->status);
 155                 rv = ERR_PTR(-EINVAL);
 156                 goto out;
 157         }
 158
 159         bd = blkdev_get_by_dev(MKDEV(reply->major, reply->minor),
 160                                FMODE_READ, NULL);
 161         if (IS_ERR(bd)) {
 162                 dprintk("%s failed to open device : %ld\n", __func__,
 163                         PTR_ERR(bd));
 164                 rv = ERR_CAST(bd);
 165                 goto out;
 166         }
 167
 168         rv = kzalloc(sizeof(*rv), GFP_NOFS);
 169         if (!rv) {
 170                 rv = ERR_PTR(-ENOMEM);
 171                 goto out;
 172         }
 173
 174         rv->bm_mdev = bd;
 175         memcpy(&rv->bm_mdevid, &dev->dev_id, sizeof(struct nfs4_deviceid));
 176         rv->net = net;
 177         dprintk("%s Created device %s with bd_block_size %u\n",
 178                 __func__,
 179                 bd->bd_disk->disk_name,
 180                 bd->bd_block_size);
 181
 182 out:
 183         kfree(msg->data);
 184         return rv;
 185 }
 186
 187 /* Map deviceid returned by the server to constructed block_device */
 188 static struct block_device *translate_devid(struct pnfs_layout_hdr *lo,
 189                                             struct nfs4_deviceid *id)
 190 {
 191         struct block_device *rv = NULL;
 192         struct block_mount_id *mid;
 193         struct pnfs_block_dev *dev;
 194
 195         dprintk("%s enter, lo=%p, id=%p\n", __func__, lo, id);
 196         mid = BLK_ID(lo);
 197         spin_lock(&mid->bm_lock);
 198         list_for_each_entry(dev, &mid->bm_devlist, bm_node) {
 199                 if (memcmp(id->data, dev->bm_mdevid.data,
 200                            NFS4_DEVICEID4_SIZE) == 0) {
 201                         rv = dev->bm_mdev;
 202                         goto out;
 203                 }
 204         }
 205  out:
 206         spin_unlock(&mid->bm_lock);
 207         dprintk("%s returning %p\n", __func__, rv);
 208         return rv;
 209 }
 210
 211 /* Tracks info needed to ensure extents in layout obey constraints of spec */
 212 struct layout_verification {
 213         u32 mode;       /* R or RW */
 214         u64 start;      /* Expected start of next non-COW extent */
 215         u64 inval;      /* Start of INVAL coverage */
 216         u64 cowread;    /* End of COW read coverage */
 217 };
 218
 219 /* Verify the extent meets the layout requirements of the pnfs-block draft,
 220  * section 2.3.1.
 221  */
 222 static int verify_extent(struct pnfs_block_extent *be,
 223                          struct layout_verification *lv)
 224 {
 225         if (lv->mode == IOMODE_READ) {
 226                 if (be->be_state == PNFS_BLOCK_READWRITE_DATA ||
 227                     be->be_state == PNFS_BLOCK_INVALID_DATA)
 228                         return -EIO;
 229                 if (be->be_f_offset != lv->start)
 230                         return -EIO;
 231                 lv->start += be->be_length;
 232                 return 0;
 233         }
 234         /* lv->mode == IOMODE_RW */
 235         if (be->be_state == PNFS_BLOCK_READWRITE_DATA) {
 236                 if (be->be_f_offset != lv->start)
 237                         return -EIO;
 238                 if (lv->cowread > lv->start)
 239                         return -EIO;
 240                 lv->start += be->be_length;
 241                 lv->inval = lv->start;
 242                 return 0;
 243         } else if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
 244                 if (be->be_f_offset != lv->start)
 245                         return -EIO;
 246                 lv->start += be->be_length;
 247                 return 0;
 248         } else if (be->be_state == PNFS_BLOCK_READ_DATA) {
 249                 if (be->be_f_offset > lv->start)
 250                         return -EIO;
 251                 if (be->be_f_offset < lv->inval)
 252                         return -EIO;
 253                 if (be->be_f_offset < lv->cowread)
 254                         return -EIO;
 255                 /* It looks like you might want to min this with lv->start,
 256                  * but you really don't.
 257                  */
 258                 lv->inval = lv->inval + be->be_length;
 259                 lv->cowread = be->be_f_offset + be->be_length;
 260                 return 0;
 261         } else
 262                 return -EIO;
 263 }
 264
 265 /* XDR decode pnfs_block_layout4 structure */
 266 int
 267 nfs4_blk_process_layoutget(struct pnfs_layout_hdr *lo,
 268                            struct nfs4_layoutget_res *lgr, gfp_t gfp_flags)
 269 {
 270         struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
 271         int i, status = -EIO;
 272         uint32_t count;
 273         struct pnfs_block_extent *be = NULL, *save;
 274         struct xdr_stream stream;
 275         struct xdr_buf buf;
 276         struct page *scratch;
 277         __be32 *p;
 278         struct layout_verification lv = {
 279                 .mode = lgr->range.iomode,
 280                 .start = lgr->range.offset >> SECTOR_SHIFT,
 281                 .inval = lgr->range.offset >> SECTOR_SHIFT,
 282                 .cowread = lgr->range.offset >> SECTOR_SHIFT,
 283         };
 284         LIST_HEAD(extents);
 285
 286         dprintk("---> %s\n", __func__);
 287
 288         scratch = alloc_page(gfp_flags);
 289         if (!scratch)
 290                 return -ENOMEM;
 291
 292         xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
 293         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 294
 295         p = xdr_inline_decode(&stream, 4);
 296         if (unlikely(!p))
 297                 goto out_err;
 298
 299         count = be32_to_cpup(p++);
 300
 301         dprintk("%s enter, number of extents %i\n", __func__, count);
 302         p = xdr_inline_decode(&stream, (28 + NFS4_DEVICEID4_SIZE) * count);
 303         if (unlikely(!p))
 304                 goto out_err;
 305
 306         /* Decode individual extents, putting them in temporary
 307          * staging area until whole layout is decoded to make error
 308          * recovery easier.
 309          */
 310         for (i = 0; i < count; i++) {
 311                 be = bl_alloc_extent();
 312                 if (!be) {
 313                         status = -ENOMEM;
 314                         goto out_err;
 315                 }
 316                 memcpy(&be->be_devid, p, NFS4_DEVICEID4_SIZE);
 317                 p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
 318                 be->be_mdev = translate_devid(lo, &be->be_devid);
 319                 if (!be->be_mdev)
 320                         goto out_err;
 321
 322                 /* The next three values are read in as bytes,
 323                  * but stored as 512-byte sector lengths
 324                  */
 325                 if (decode_sector_number(&p, &be->be_f_offset) < 0)
 326                         goto out_err;
 327                 if (decode_sector_number(&p, &be->be_length) < 0)
 328                         goto out_err;
 329                 if (decode_sector_number(&p, &be->be_v_offset) < 0)
 330                         goto out_err;
 331                 be->be_state = be32_to_cpup(p++);
 332                 if (be->be_state == PNFS_BLOCK_INVALID_DATA)
 333                         be->be_inval = &bl->bl_inval;
 334                 if (verify_extent(be, &lv)) {
 335                         dprintk("%s verify failed\n", __func__);
 336                         goto out_err;
 337                 }
 338                 list_add_tail(&be->be_node, &extents);
 339         }
 340         if (lgr->range.offset + lgr->range.length !=
 341                         lv.start << SECTOR_SHIFT) {
 342                 dprintk("%s Final length mismatch\n", __func__);
 343                 be = NULL;
 344                 goto out_err;
 345         }
 346         if (lv.start < lv.cowread) {
 347                 dprintk("%s Final uncovered COW extent\n", __func__);
 348                 be = NULL;
 349                 goto out_err;
 350         }
 351         /* Extents decoded properly, now try to merge them in to
 352          * existing layout extents.
 353          */
 354         spin_lock(&bl->bl_ext_lock);
 355         list_for_each_entry_safe(be, save, &extents, be_node) {
 356                 list_del(&be->be_node);
 357                 status = bl_add_merge_extent(bl, be);
 358                 if (status) {
 359                         spin_unlock(&bl->bl_ext_lock);
 360                         /* This is a fairly catastrophic error, as the
 361                          * entire layout extent lists are now corrupted.
 362                          * We should have some way to distinguish this.
 363                          */
 364                         be = NULL;
 365                         goto out_err;
 366                 }
 367         }
 368         spin_unlock(&bl->bl_ext_lock);
 369         status = 0;
 370  out:
 371         __free_page(scratch);
 372         dprintk("%s returns %i\n", __func__, status);
 373         return status;
 374
 375  out_err:
 376         bl_put_extent(be);
 377         while (!list_empty(&extents)) {
 378                 be = list_first_entry(&extents, struct pnfs_block_extent,
 379                                       be_node);
 380                 list_del(&be->be_node);
 381                 bl_put_extent(be);
 382         }
 383         goto out;
 384 }