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 "%s: sector not aligned\n", __func__);
  50                 return -1;
  51         }
  52         *sp = s >> SECTOR_SHIFT;
  53         return 0;
  54 }
  55
  56 /* Open a block_device by device number. */
  57 struct block_device *nfs4_blkdev_get(dev_t dev)
  58 {
  59         struct block_device *bd;
  60
  61         dprintk("%s enter\n", __func__);
  62         bd = blkdev_get_by_dev(dev, FMODE_READ, NULL);
  63         if (IS_ERR(bd))
  64                 goto fail;
  65         return bd;
  66 fail:
  67         dprintk("%s failed to open device : %ld\n",
  68                         __func__, PTR_ERR(bd));
  69         return NULL;
  70 }
  71
  72 /*
  73  * Release the block device
  74  */
  75 int nfs4_blkdev_put(struct block_device *bdev)
  76 {
  77         dprintk("%s for device %d:%d\n", __func__, MAJOR(bdev->bd_dev),
  78                         MINOR(bdev->bd_dev));
  79         return blkdev_put(bdev, FMODE_READ);
  80 }
  81
  82 static struct bl_dev_msg bl_mount_reply;
  83
  84 ssize_t bl_pipe_downcall(struct file *filp, const char __user *src,
  85                          size_t mlen)
  86 {
  87         if (mlen != sizeof (struct bl_dev_msg))
  88                 return -EINVAL;
  89
  90         if (copy_from_user(&bl_mount_reply, src, mlen) != 0)
  91                 return -EFAULT;
  92
  93         wake_up(&bl_wq);
  94
  95         return mlen;
  96 }
  97
  98 void bl_pipe_destroy_msg(struct rpc_pipe_msg *msg)
  99 {
 100         if (msg->errno >= 0)
 101                 return;
 102         wake_up(&bl_wq);
 103 }
 104
 105 /*
 106  * Decodes pnfs_block_deviceaddr4 which is XDR encoded in dev->dev_addr_buf.
 107  */
 108 struct pnfs_block_dev *
 109 nfs4_blk_decode_device(struct nfs_server *server,
 110                        struct pnfs_device *dev)
 111 {
 112         struct pnfs_block_dev *rv;
 113         struct block_device *bd = NULL;
 114         struct rpc_pipe_msg msg;
 115         struct bl_msg_hdr bl_msg = {
 116                 .type = BL_DEVICE_MOUNT,
 117                 .totallen = dev->mincount,
 118         };
 119         uint8_t *dataptr;
 120         DECLARE_WAITQUEUE(wq, current);
 121         struct bl_dev_msg *reply = &bl_mount_reply;
 122         int offset, len, i, rc;
 123
 124         dprintk("%s CREATING PIPEFS MESSAGE\n", __func__);
 125         dprintk("%s: deviceid: %s, mincount: %d\n", __func__, dev->dev_id.data,
 126                 dev->mincount);
 127
 128         memset(&msg, 0, sizeof(msg));
 129         msg.data = kzalloc(sizeof(bl_msg) + dev->mincount, GFP_NOFS);
 130         if (!msg.data) {
 131                 rv = ERR_PTR(-ENOMEM);
 132                 goto out;
 133         }
 134
 135         memcpy(msg.data, &bl_msg, sizeof(bl_msg));
 136         dataptr = (uint8_t *) msg.data;
 137         len = dev->mincount;
 138         offset = sizeof(bl_msg);
 139         for (i = 0; len > 0; i++) {
 140                 memcpy(&dataptr[offset], page_address(dev->pages[i]),
 141                                 len < PAGE_CACHE_SIZE ? len : PAGE_CACHE_SIZE);
 142                 len -= PAGE_CACHE_SIZE;
 143                 offset += PAGE_CACHE_SIZE;
 144         }
 145         msg.len = sizeof(bl_msg) + dev->mincount;
 146
 147         dprintk("%s CALLING USERSPACE DAEMON\n", __func__);
 148         add_wait_queue(&bl_wq, &wq);
 149         rc = rpc_queue_upcall(bl_device_pipe->d_inode, &msg);
 150         if (rc < 0) {
 151                 remove_wait_queue(&bl_wq, &wq);
 152                 rv = ERR_PTR(rc);
 153                 goto out;
 154         }
 155
 156         set_current_state(TASK_UNINTERRUPTIBLE);
 157         schedule();
 158         __set_current_state(TASK_RUNNING);
 159         remove_wait_queue(&bl_wq, &wq);
 160
 161         if (reply->status != BL_DEVICE_REQUEST_PROC) {
 162                 dprintk("%s failed to open device: %d\n",
 163                         __func__, reply->status);
 164                 rv = ERR_PTR(-EINVAL);
 165                 goto out;
 166         }
 167
 168         bd = nfs4_blkdev_get(MKDEV(reply->major, reply->minor));
 169         if (IS_ERR(bd)) {
 170                 rc = PTR_ERR(bd);
 171                 dprintk("%s failed to open device : %d\n", __func__, rc);
 172                 rv = ERR_PTR(rc);
 173                 goto out;
 174         }
 175
 176         rv = kzalloc(sizeof(*rv), GFP_NOFS);
 177         if (!rv) {
 178                 rv = ERR_PTR(-ENOMEM);
 179                 goto out;
 180         }
 181
 182         rv->bm_mdev = bd;
 183         memcpy(&rv->bm_mdevid, &dev->dev_id, sizeof(struct nfs4_deviceid));
 184         dprintk("%s Created device %s with bd_block_size %u\n",
 185                 __func__,
 186                 bd->bd_disk->disk_name,
 187                 bd->bd_block_size);
 188
 189 out:
 190         kfree(msg.data);
 191         return rv;
 192 }
 193
 194 /* Map deviceid returned by the server to constructed block_device */
 195 static struct block_device *translate_devid(struct pnfs_layout_hdr *lo,
 196                                             struct nfs4_deviceid *id)
 197 {
 198         struct block_device *rv = NULL;
 199         struct block_mount_id *mid;
 200         struct pnfs_block_dev *dev;
 201
 202         dprintk("%s enter, lo=%p, id=%p\n", __func__, lo, id);
 203         mid = BLK_ID(lo);
 204         spin_lock(&mid->bm_lock);
 205         list_for_each_entry(dev, &mid->bm_devlist, bm_node) {
 206                 if (memcmp(id->data, dev->bm_mdevid.data,
 207                            NFS4_DEVICEID4_SIZE) == 0) {
 208                         rv = dev->bm_mdev;
 209                         goto out;
 210                 }
 211         }
 212  out:
 213         spin_unlock(&mid->bm_lock);
 214         dprintk("%s returning %p\n", __func__, rv);
 215         return rv;
 216 }
 217
 218 /* Tracks info needed to ensure extents in layout obey constraints of spec */
 219 struct layout_verification {
 220         u32 mode;       /* R or RW */
 221         u64 start;      /* Expected start of next non-COW extent */
 222         u64 inval;      /* Start of INVAL coverage */
 223         u64 cowread;    /* End of COW read coverage */
 224 };
 225
 226 /* Verify the extent meets the layout requirements of the pnfs-block draft,
 227  * section 2.3.1.
 228  */
 229 static int verify_extent(struct pnfs_block_extent *be,
 230                          struct layout_verification *lv)
 231 {
 232         if (lv->mode == IOMODE_READ) {
 233                 if (be->be_state == PNFS_BLOCK_READWRITE_DATA ||
 234                     be->be_state == PNFS_BLOCK_INVALID_DATA)
 235                         return -EIO;
 236                 if (be->be_f_offset != lv->start)
 237                         return -EIO;
 238                 lv->start += be->be_length;
 239                 return 0;
 240         }
 241         /* lv->mode == IOMODE_RW */
 242         if (be->be_state == PNFS_BLOCK_READWRITE_DATA) {
 243                 if (be->be_f_offset != lv->start)
 244                         return -EIO;
 245                 if (lv->cowread > lv->start)
 246                         return -EIO;
 247                 lv->start += be->be_length;
 248                 lv->inval = lv->start;
 249                 return 0;
 250         } else if (be->be_state == PNFS_BLOCK_INVALID_DATA) {
 251                 if (be->be_f_offset != lv->start)
 252                         return -EIO;
 253                 lv->start += be->be_length;
 254                 return 0;
 255         } else if (be->be_state == PNFS_BLOCK_READ_DATA) {
 256                 if (be->be_f_offset > lv->start)
 257                         return -EIO;
 258                 if (be->be_f_offset < lv->inval)
 259                         return -EIO;
 260                 if (be->be_f_offset < lv->cowread)
 261                         return -EIO;
 262                 /* It looks like you might want to min this with lv->start,
 263                  * but you really don't.
 264                  */
 265                 lv->inval = lv->inval + be->be_length;
 266                 lv->cowread = be->be_f_offset + be->be_length;
 267                 return 0;
 268         } else
 269                 return -EIO;
 270 }
 271
 272 /* XDR decode pnfs_block_layout4 structure */
 273 int
 274 nfs4_blk_process_layoutget(struct pnfs_layout_hdr *lo,
 275                            struct nfs4_layoutget_res *lgr, gfp_t gfp_flags)
 276 {
 277         struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
 278         int i, status = -EIO;
 279         uint32_t count;
 280         struct pnfs_block_extent *be = NULL, *save;
 281         struct xdr_stream stream;
 282         struct xdr_buf buf;
 283         struct page *scratch;
 284         __be32 *p;
 285         struct layout_verification lv = {
 286                 .mode = lgr->range.iomode,
 287                 .start = lgr->range.offset >> SECTOR_SHIFT,
 288                 .inval = lgr->range.offset >> SECTOR_SHIFT,
 289                 .cowread = lgr->range.offset >> SECTOR_SHIFT,
 290         };
 291         LIST_HEAD(extents);
 292
 293         dprintk("---> %s\n", __func__);
 294
 295         scratch = alloc_page(gfp_flags);
 296         if (!scratch)
 297                 return -ENOMEM;
 298
 299         xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
 300         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 301
 302         p = xdr_inline_decode(&stream, 4);
 303         if (unlikely(!p))
 304                 goto out_err;
 305
 306         count = be32_to_cpup(p++);
 307
 308         dprintk("%s enter, number of extents %i\n", __func__, count);
 309         p = xdr_inline_decode(&stream, (28 + NFS4_DEVICEID4_SIZE) * count);
 310         if (unlikely(!p))
 311                 goto out_err;
 312
 313         /* Decode individual extents, putting them in temporary
 314          * staging area until whole layout is decoded to make error
 315          * recovery easier.
 316          */
 317         for (i = 0; i < count; i++) {
 318                 be = bl_alloc_extent();
 319                 if (!be) {
 320                         status = -ENOMEM;
 321                         goto out_err;
 322                 }
 323                 memcpy(&be->be_devid, p, NFS4_DEVICEID4_SIZE);
 324                 p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
 325                 be->be_mdev = translate_devid(lo, &be->be_devid);
 326                 if (!be->be_mdev)
 327                         goto out_err;
 328
 329                 /* The next three values are read in as bytes,
 330                  * but stored as 512-byte sector lengths
 331                  */
 332                 if (decode_sector_number(&p, &be->be_f_offset) < 0)
 333                         goto out_err;
 334                 if (decode_sector_number(&p, &be->be_length) < 0)
 335                         goto out_err;
 336                 if (decode_sector_number(&p, &be->be_v_offset) < 0)
 337                         goto out_err;
 338                 be->be_state = be32_to_cpup(p++);
 339                 if (be->be_state == PNFS_BLOCK_INVALID_DATA)
 340                         be->be_inval = &bl->bl_inval;
 341                 if (verify_extent(be, &lv)) {
 342                         dprintk("%s verify failed\n", __func__);
 343                         goto out_err;
 344                 }
 345                 list_add_tail(&be->be_node, &extents);
 346         }
 347         if (lgr->range.offset + lgr->range.length !=
 348                         lv.start << SECTOR_SHIFT) {
 349                 dprintk("%s Final length mismatch\n", __func__);
 350                 be = NULL;
 351                 goto out_err;
 352         }
 353         if (lv.start < lv.cowread) {
 354                 dprintk("%s Final uncovered COW extent\n", __func__);
 355                 be = NULL;
 356                 goto out_err;
 357         }
 358         /* Extents decoded properly, now try to merge them in to
 359          * existing layout extents.
 360          */
 361         spin_lock(&bl->bl_ext_lock);
 362         list_for_each_entry_safe(be, save, &extents, be_node) {
 363                 list_del(&be->be_node);
 364                 status = bl_add_merge_extent(bl, be);
 365                 if (status) {
 366                         spin_unlock(&bl->bl_ext_lock);
 367                         /* This is a fairly catastrophic error, as the
 368                          * entire layout extent lists are now corrupted.
 369                          * We should have some way to distinguish this.
 370                          */
 371                         be = NULL;
 372                         goto out_err;
 373                 }
 374         }
 375         spin_unlock(&bl->bl_ext_lock);
 376         status = 0;
 377  out:
 378         __free_page(scratch);
 379         dprintk("%s returns %i\n", __func__, status);
 380         return status;
 381
 382  out_err:
 383         bl_put_extent(be);
 384         while (!list_empty(&extents)) {
 385                 be = list_first_entry(&extents, struct pnfs_block_extent,
 386                                       be_node);
 387                 list_del(&be->be_node);
 388                 bl_put_extent(be);
 389         }
 390         goto out;
 391 }