fs/erofs/data.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2017-2018 HUAWEI, Inc.
   4  *             https://www.huawei.com/
   5  * Copyright (C) 2021, Alibaba Cloud
   6  */
   7 #include "internal.h"
   8 #include <linux/prefetch.h>
   9 #include <linux/dax.h>
  10 #include <trace/events/erofs.h>
  11
  12 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
  13 {
  14         struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;
  15         struct page *page;
  16
  17         page = read_cache_page_gfp(mapping, blkaddr,
  18                                    mapping_gfp_constraint(mapping, ~__GFP_FS));
  19         /* should already be PageUptodate */
  20         if (!IS_ERR(page))
  21                 lock_page(page);
  22         return page;
  23 }
  24
  25 static int erofs_map_blocks_flatmode(struct inode *inode,
  26                                      struct erofs_map_blocks *map,
  27                                      int flags)
  28 {
  29         int err = 0;
  30         erofs_blk_t nblocks, lastblk;
  31         u64 offset = map->m_la;
  32         struct erofs_inode *vi = EROFS_I(inode);
  33         bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
  34
  35         trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
  36
  37         nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
  38         lastblk = nblocks - tailendpacking;
  39
  40         /* there is no hole in flatmode */
  41         map->m_flags = EROFS_MAP_MAPPED;
  42
  43         if (offset < blknr_to_addr(lastblk)) {
  44                 map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
  45                 map->m_plen = blknr_to_addr(lastblk) - offset;
  46         } else if (tailendpacking) {
  47                 /* 2 - inode inline B: inode, [xattrs], inline last blk... */
  48                 struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
  49
  50                 map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
  51                         vi->xattr_isize + erofs_blkoff(map->m_la);
  52                 map->m_plen = inode->i_size - offset;
  53
  54                 /* inline data should be located in one meta block */
  55                 if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
  56                         erofs_err(inode->i_sb,
  57                                   "inline data cross block boundary @ nid %llu",
  58                                   vi->nid);
  59                         DBG_BUGON(1);
  60                         err = -EFSCORRUPTED;
  61                         goto err_out;
  62                 }
  63
  64                 map->m_flags |= EROFS_MAP_META;
  65         } else {
  66                 erofs_err(inode->i_sb,
  67                           "internal error @ nid: %llu (size %llu), m_la 0x%llx",
  68                           vi->nid, inode->i_size, map->m_la);
  69                 DBG_BUGON(1);
  70                 err = -EIO;
  71                 goto err_out;
  72         }
  73
  74         map->m_llen = map->m_plen;
  75 err_out:
  76         trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
  77         return err;
  78 }
  79
  80 static int erofs_map_blocks(struct inode *inode,
  81                             struct erofs_map_blocks *map, int flags)
  82 {
  83         struct super_block *sb = inode->i_sb;
  84         struct erofs_inode *vi = EROFS_I(inode);
  85         struct erofs_inode_chunk_index *idx;
  86         struct page *page;
  87         u64 chunknr;
  88         unsigned int unit;
  89         erofs_off_t pos;
  90         int err = 0;
  91
  92         map->m_deviceid = 0;
  93         if (map->m_la >= inode->i_size) {
  94                 /* leave out-of-bound access unmapped */
  95                 map->m_flags = 0;
  96                 map->m_plen = 0;
  97                 goto out;
  98         }
  99
 100         if (vi->datalayout != EROFS_INODE_CHUNK_BASED)
 101                 return erofs_map_blocks_flatmode(inode, map, flags);
 102
 103         if (vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES)
 104                 unit = sizeof(*idx);                    /* chunk index */
 105         else
 106                 unit = EROFS_BLOCK_MAP_ENTRY_SIZE;      /* block map */
 107
 108         chunknr = map->m_la >> vi->chunkbits;
 109         pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
 110                     vi->xattr_isize, unit) + unit * chunknr;
 111
 112         page = erofs_get_meta_page(inode->i_sb, erofs_blknr(pos));
 113         if (IS_ERR(page))
 114                 return PTR_ERR(page);
 115
 116         map->m_la = chunknr << vi->chunkbits;
 117         map->m_plen = min_t(erofs_off_t, 1UL << vi->chunkbits,
 118                             roundup(inode->i_size - map->m_la, EROFS_BLKSIZ));
 119
 120         /* handle block map */
 121         if (!(vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES)) {
 122                 __le32 *blkaddr = page_address(page) + erofs_blkoff(pos);
 123
 124                 if (le32_to_cpu(*blkaddr) == EROFS_NULL_ADDR) {
 125                         map->m_flags = 0;
 126                 } else {
 127                         map->m_pa = blknr_to_addr(le32_to_cpu(*blkaddr));
 128                         map->m_flags = EROFS_MAP_MAPPED;
 129                 }
 130                 goto out_unlock;
 131         }
 132         /* parse chunk indexes */
 133         idx = page_address(page) + erofs_blkoff(pos);
 134         switch (le32_to_cpu(idx->blkaddr)) {
 135         case EROFS_NULL_ADDR:
 136                 map->m_flags = 0;
 137                 break;
 138         default:
 139                 map->m_deviceid = le16_to_cpu(idx->device_id) &
 140                         EROFS_SB(sb)->device_id_mask;
 141                 map->m_pa = blknr_to_addr(le32_to_cpu(idx->blkaddr));
 142                 map->m_flags = EROFS_MAP_MAPPED;
 143                 break;
 144         }
 145 out_unlock:
 146         unlock_page(page);
 147         put_page(page);
 148 out:
 149         map->m_llen = map->m_plen;
 150         return err;
 151 }
 152
 153 int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 154 {
 155         struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
 156         struct erofs_device_info *dif;
 157         int id;
 158
 159         /* primary device by default */
 160         map->m_bdev = sb->s_bdev;
 161         map->m_daxdev = EROFS_SB(sb)->dax_dev;
 162
 163         if (map->m_deviceid) {
 164                 down_read(&devs->rwsem);
 165                 dif = idr_find(&devs->tree, map->m_deviceid - 1);
 166                 if (!dif) {
 167                         up_read(&devs->rwsem);
 168                         return -ENODEV;
 169                 }
 170                 map->m_bdev = dif->bdev;
 171                 map->m_daxdev = dif->dax_dev;
 172                 up_read(&devs->rwsem);
 173         } else if (devs->extra_devices) {
 174                 down_read(&devs->rwsem);
 175                 idr_for_each_entry(&devs->tree, dif, id) {
 176                         erofs_off_t startoff, length;
 177
 178                         if (!dif->mapped_blkaddr)
 179                                 continue;
 180                         startoff = blknr_to_addr(dif->mapped_blkaddr);
 181                         length = blknr_to_addr(dif->blocks);
 182
 183                         if (map->m_pa >= startoff &&
 184                             map->m_pa < startoff + length) {
 185                                 map->m_pa -= startoff;
 186                                 map->m_bdev = dif->bdev;
 187                                 map->m_daxdev = dif->dax_dev;
 188                                 break;
 189                         }
 190                 }
 191                 up_read(&devs->rwsem);
 192         }
 193         return 0;
 194 }
 195
 196 static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 197                 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
 198 {
 199         int ret;
 200         struct erofs_map_blocks map;
 201         struct erofs_map_dev mdev;
 202
 203         map.m_la = offset;
 204         map.m_llen = length;
 205
 206         ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
 207         if (ret < 0)
 208                 return ret;
 209
 210         mdev = (struct erofs_map_dev) {
 211                 .m_deviceid = map.m_deviceid,
 212                 .m_pa = map.m_pa,
 213         };
 214         ret = erofs_map_dev(inode->i_sb, &mdev);
 215         if (ret)
 216                 return ret;
 217
 218         iomap->bdev = mdev.m_bdev;
 219         iomap->dax_dev = mdev.m_daxdev;
 220         iomap->offset = map.m_la;
 221         iomap->length = map.m_llen;
 222         iomap->flags = 0;
 223         iomap->private = NULL;
 224
 225         if (!(map.m_flags & EROFS_MAP_MAPPED)) {
 226                 iomap->type = IOMAP_HOLE;
 227                 iomap->addr = IOMAP_NULL_ADDR;
 228                 if (!iomap->length)
 229                         iomap->length = length;
 230                 return 0;
 231         }
 232
 233         if (map.m_flags & EROFS_MAP_META) {
 234                 struct page *ipage;
 235
 236                 iomap->type = IOMAP_INLINE;
 237                 ipage = erofs_get_meta_page(inode->i_sb,
 238                                             erofs_blknr(mdev.m_pa));
 239                 if (IS_ERR(ipage))
 240                         return PTR_ERR(ipage);
 241                 iomap->inline_data = page_address(ipage) +
 242                                         erofs_blkoff(mdev.m_pa);
 243                 iomap->private = ipage;
 244         } else {
 245                 iomap->type = IOMAP_MAPPED;
 246                 iomap->addr = mdev.m_pa;
 247         }
 248         return 0;
 249 }
 250
 251 static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
 252                 ssize_t written, unsigned int flags, struct iomap *iomap)
 253 {
 254         struct page *ipage = iomap->private;
 255
 256         if (ipage) {
 257                 DBG_BUGON(iomap->type != IOMAP_INLINE);
 258                 unlock_page(ipage);
 259                 put_page(ipage);
 260         } else {
 261                 DBG_BUGON(iomap->type == IOMAP_INLINE);
 262         }
 263         return written;
 264 }
 265
 266 static const struct iomap_ops erofs_iomap_ops = {
 267         .iomap_begin = erofs_iomap_begin,
 268         .iomap_end = erofs_iomap_end,
 269 };
 270
 271 int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 272                  u64 start, u64 len)
 273 {
 274         if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
 275 #ifdef CONFIG_EROFS_FS_ZIP
 276                 return iomap_fiemap(inode, fieinfo, start, len,
 277                                     &z_erofs_iomap_report_ops);
 278 #else
 279                 return -EOPNOTSUPP;
 280 #endif
 281         }
 282         return iomap_fiemap(inode, fieinfo, start, len, &erofs_iomap_ops);
 283 }
 284
 285 /*
 286  * since we dont have write or truncate flows, so no inode
 287  * locking needs to be held at the moment.
 288  */
 289 static int erofs_readpage(struct file *file, struct page *page)
 290 {
 291         return iomap_readpage(page, &erofs_iomap_ops);
 292 }
 293
 294 static void erofs_readahead(struct readahead_control *rac)
 295 {
 296         return iomap_readahead(rac, &erofs_iomap_ops);
 297 }
 298
 299 static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
 300 {
 301         return iomap_bmap(mapping, block, &erofs_iomap_ops);
 302 }
 303
 304 static int erofs_prepare_dio(struct kiocb *iocb, struct iov_iter *to)
 305 {
 306         struct inode *inode = file_inode(iocb->ki_filp);
 307         loff_t align = iocb->ki_pos | iov_iter_count(to) |
 308                 iov_iter_alignment(to);
 309         struct block_device *bdev = inode->i_sb->s_bdev;
 310         unsigned int blksize_mask;
 311
 312         if (bdev)
 313                 blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1;
 314         else
 315                 blksize_mask = (1 << inode->i_blkbits) - 1;
 316
 317         if (align & blksize_mask)
 318                 return -EINVAL;
 319         return 0;
 320 }
 321
 322 static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 323 {
 324         /* no need taking (shared) inode lock since it's a ro filesystem */
 325         if (!iov_iter_count(to))
 326                 return 0;
 327
 328 #ifdef CONFIG_FS_DAX
 329         if (IS_DAX(iocb->ki_filp->f_mapping->host))
 330                 return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
 331 #endif
 332         if (iocb->ki_flags & IOCB_DIRECT) {
 333                 int err = erofs_prepare_dio(iocb, to);
 334
 335                 if (!err)
 336                         return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
 337                                             NULL, 0, 0);
 338                 if (err < 0)
 339                         return err;
 340         }
 341         return filemap_read(iocb, to, 0);
 342 }
 343
 344 /* for uncompressed (aligned) files and raw access for other files */
 345 const struct address_space_operations erofs_raw_access_aops = {
 346         .readpage = erofs_readpage,
 347         .readahead = erofs_readahead,
 348         .bmap = erofs_bmap,
 349         .direct_IO = noop_direct_IO,
 350 };
 351
 352 #ifdef CONFIG_FS_DAX
 353 static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf,
 354                 enum page_entry_size pe_size)
 355 {
 356         return dax_iomap_fault(vmf, pe_size, NULL, NULL, &erofs_iomap_ops);
 357 }
 358
 359 static vm_fault_t erofs_dax_fault(struct vm_fault *vmf)
 360 {
 361         return erofs_dax_huge_fault(vmf, PE_SIZE_PTE);
 362 }
 363
 364 static const struct vm_operations_struct erofs_dax_vm_ops = {
 365         .fault          = erofs_dax_fault,
 366         .huge_fault     = erofs_dax_huge_fault,
 367 };
 368
 369 static int erofs_file_mmap(struct file *file, struct vm_area_struct *vma)
 370 {
 371         if (!IS_DAX(file_inode(file)))
 372                 return generic_file_readonly_mmap(file, vma);
 373
 374         if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
 375                 return -EINVAL;
 376
 377         vma->vm_ops = &erofs_dax_vm_ops;
 378         vma->vm_flags |= VM_HUGEPAGE;
 379         return 0;
 380 }
 381 #else
 382 #define erofs_file_mmap generic_file_readonly_mmap
 383 #endif
 384
 385 const struct file_operations erofs_file_fops = {
 386         .llseek         = generic_file_llseek,
 387         .read_iter      = erofs_file_read_iter,
 388         .mmap           = erofs_file_mmap,
 389         .splice_read    = generic_file_splice_read,
 390 };