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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * linux/fs/adfs/inode.c4 *5 * Copyright (C) 1997-1999 Russell King6 */7#include <linux/buffer_head.h>8#include <linux/mpage.h>9#include <linux/writeback.h>10#include "adfs.h"11 12/*13 * Lookup/Create a block at offset 'block' into 'inode'. We currently do14 * not support creation of new blocks, so we return -EIO for this case.15 */16static int17adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,18 int create)19{20 if (!create) {21 if (block >= inode->i_blocks)22 goto abort_toobig;23 24 block = __adfs_block_map(inode->i_sb, ADFS_I(inode)->indaddr,25 block);26 if (block)27 map_bh(bh, inode->i_sb, block);28 return 0;29 }30 /* don't support allocation of blocks yet */31 return -EIO;32 33abort_toobig:34 return 0;35}36 37static int adfs_writepages(struct address_space *mapping,38 struct writeback_control *wbc)39{40 return mpage_writepages(mapping, wbc, adfs_get_block);41}42 43static int adfs_read_folio(struct file *file, struct folio *folio)44{45 return block_read_full_folio(folio, adfs_get_block);46}47 48static void adfs_write_failed(struct address_space *mapping, loff_t to)49{50 struct inode *inode = mapping->host;51 52 if (to > inode->i_size)53 truncate_pagecache(inode, inode->i_size);54}55 56static int adfs_write_begin(struct file *file, struct address_space *mapping,57 loff_t pos, unsigned len,58 struct folio **foliop, void **fsdata)59{60 int ret;61 62 ret = cont_write_begin(file, mapping, pos, len, foliop, fsdata,63 adfs_get_block,64 &ADFS_I(mapping->host)->mmu_private);65 if (unlikely(ret))66 adfs_write_failed(mapping, pos + len);67 68 return ret;69}70 71static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)72{73 return generic_block_bmap(mapping, block, adfs_get_block);74}75 76static const struct address_space_operations adfs_aops = {77 .dirty_folio = block_dirty_folio,78 .invalidate_folio = block_invalidate_folio,79 .read_folio = adfs_read_folio,80 .writepages = adfs_writepages,81 .write_begin = adfs_write_begin,82 .write_end = generic_write_end,83 .migrate_folio = buffer_migrate_folio,84 .bmap = _adfs_bmap,85};86 87/*88 * Convert ADFS attributes and filetype to Linux permission.89 */90static umode_t91adfs_atts2mode(struct super_block *sb, struct inode *inode)92{93 unsigned int attr = ADFS_I(inode)->attr;94 umode_t mode, rmask;95 struct adfs_sb_info *asb = ADFS_SB(sb);96 97 if (attr & ADFS_NDA_DIRECTORY) {98 mode = S_IRUGO & asb->s_owner_mask;99 return S_IFDIR | S_IXUGO | mode;100 }101 102 switch (adfs_filetype(ADFS_I(inode)->loadaddr)) {103 case 0xfc0: /* LinkFS */104 return S_IFLNK|S_IRWXUGO;105 106 case 0xfe6: /* UnixExec */107 rmask = S_IRUGO | S_IXUGO;108 break;109 110 default:111 rmask = S_IRUGO;112 }113 114 mode = S_IFREG;115 116 if (attr & ADFS_NDA_OWNER_READ)117 mode |= rmask & asb->s_owner_mask;118 119 if (attr & ADFS_NDA_OWNER_WRITE)120 mode |= S_IWUGO & asb->s_owner_mask;121 122 if (attr & ADFS_NDA_PUBLIC_READ)123 mode |= rmask & asb->s_other_mask;124 125 if (attr & ADFS_NDA_PUBLIC_WRITE)126 mode |= S_IWUGO & asb->s_other_mask;127 return mode;128}129 130/*131 * Convert Linux permission to ADFS attribute. We try to do the reverse132 * of atts2mode, but there is not a 1:1 translation.133 */134static int adfs_mode2atts(struct super_block *sb, struct inode *inode,135 umode_t ia_mode)136{137 struct adfs_sb_info *asb = ADFS_SB(sb);138 umode_t mode;139 int attr;140 141 /* FIXME: should we be able to alter a link? */142 if (S_ISLNK(inode->i_mode))143 return ADFS_I(inode)->attr;144 145 /* Directories do not have read/write permissions on the media */146 if (S_ISDIR(inode->i_mode))147 return ADFS_NDA_DIRECTORY;148 149 attr = 0;150 mode = ia_mode & asb->s_owner_mask;151 if (mode & S_IRUGO)152 attr |= ADFS_NDA_OWNER_READ;153 if (mode & S_IWUGO)154 attr |= ADFS_NDA_OWNER_WRITE;155 156 mode = ia_mode & asb->s_other_mask;157 mode &= ~asb->s_owner_mask;158 if (mode & S_IRUGO)159 attr |= ADFS_NDA_PUBLIC_READ;160 if (mode & S_IWUGO)161 attr |= ADFS_NDA_PUBLIC_WRITE;162 163 return attr;164}165 166static const s64 nsec_unix_epoch_diff_risc_os_epoch = 2208988800000000000LL;167 168/*169 * Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time170 * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds171 * of time to convert from RISC OS epoch to Unix epoch.172 */173static void174adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode)175{176 unsigned int high, low;177 /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since178 * 01 Jan 1900 00:00:00 (RISC OS epoch)179 */180 s64 nsec;181 182 if (!adfs_inode_is_stamped(inode))183 goto cur_time;184 185 high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */186 low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */187 188 /* convert 40-bit centi-seconds to 32-bit seconds189 * going via nanoseconds to retain precision190 */191 nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */192 193 /* Files dated pre 01 Jan 1970 00:00:00. */194 if (nsec < nsec_unix_epoch_diff_risc_os_epoch)195 goto too_early;196 197 /* convert from RISC OS to Unix epoch */198 nsec -= nsec_unix_epoch_diff_risc_os_epoch;199 200 *tv = ns_to_timespec64(nsec);201 return;202 203 cur_time:204 *tv = current_time(inode);205 return;206 207 too_early:208 tv->tv_sec = tv->tv_nsec = 0;209 return;210}211 212/* Convert an Unix time to ADFS time for an entry that is already stamped. */213static void adfs_unix2adfs_time(struct inode *inode,214 const struct timespec64 *ts)215{216 s64 cs, nsec = timespec64_to_ns(ts);217 218 /* convert from Unix to RISC OS epoch */219 nsec += nsec_unix_epoch_diff_risc_os_epoch;220 221 /* convert from nanoseconds to centiseconds */222 cs = div_s64(nsec, 10000000);223 224 cs = clamp_t(s64, cs, 0, 0xffffffffff);225 226 ADFS_I(inode)->loadaddr &= ~0xff;227 ADFS_I(inode)->loadaddr |= (cs >> 32) & 0xff;228 ADFS_I(inode)->execaddr = cs;229}230 231/*232 * Fill in the inode information from the object information.233 *234 * Note that this is an inode-less filesystem, so we can't use the inode235 * number to reference the metadata on the media. Instead, we use the236 * inode number to hold the object ID, which in turn will tell us where237 * the data is held. We also save the parent object ID, and with these238 * two, we can locate the metadata.239 *240 * This does mean that we rely on an objects parent remaining the same at241 * all times - we cannot cope with a cross-directory rename (yet).242 */243struct inode *244adfs_iget(struct super_block *sb, struct object_info *obj)245{246 struct inode *inode;247 struct timespec64 ts;248 249 inode = new_inode(sb);250 if (!inode)251 goto out;252 253 inode->i_uid = ADFS_SB(sb)->s_uid;254 inode->i_gid = ADFS_SB(sb)->s_gid;255 inode->i_ino = obj->indaddr;256 inode->i_size = obj->size;257 set_nlink(inode, 2);258 inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >>259 sb->s_blocksize_bits;260 261 /*262 * we need to save the parent directory ID so that263 * write_inode can update the directory information264 * for this file. This will need special handling265 * for cross-directory renames.266 */267 ADFS_I(inode)->parent_id = obj->parent_id;268 ADFS_I(inode)->indaddr = obj->indaddr;269 ADFS_I(inode)->loadaddr = obj->loadaddr;270 ADFS_I(inode)->execaddr = obj->execaddr;271 ADFS_I(inode)->attr = obj->attr;272 273 inode->i_mode = adfs_atts2mode(sb, inode);274 adfs_adfs2unix_time(&ts, inode);275 inode_set_atime_to_ts(inode, ts);276 inode_set_mtime_to_ts(inode, ts);277 inode_set_ctime_to_ts(inode, ts);278 279 if (S_ISDIR(inode->i_mode)) {280 inode->i_op = &adfs_dir_inode_operations;281 inode->i_fop = &adfs_dir_operations;282 } else if (S_ISREG(inode->i_mode)) {283 inode->i_op = &adfs_file_inode_operations;284 inode->i_fop = &adfs_file_operations;285 inode->i_mapping->a_ops = &adfs_aops;286 ADFS_I(inode)->mmu_private = inode->i_size;287 }288 289 inode_fake_hash(inode);290 291out:292 return inode;293}294 295/*296 * Validate and convert a changed access mode/time to their ADFS equivalents.297 * adfs_write_inode will actually write the information back to the directory298 * later.299 */300int301adfs_notify_change(struct mnt_idmap *idmap, struct dentry *dentry,302 struct iattr *attr)303{304 struct inode *inode = d_inode(dentry);305 struct super_block *sb = inode->i_sb;306 unsigned int ia_valid = attr->ia_valid;307 int error;308 309 error = setattr_prepare(&nop_mnt_idmap, dentry, attr);310 311 /*312 * we can't change the UID or GID of any file -313 * we have a global UID/GID in the superblock314 */315 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, ADFS_SB(sb)->s_uid)) ||316 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, ADFS_SB(sb)->s_gid)))317 error = -EPERM;318 319 if (error)320 goto out;321 322 /* XXX: this is missing some actual on-disk truncation.. */323 if (ia_valid & ATTR_SIZE)324 truncate_setsize(inode, attr->ia_size);325 326 if (ia_valid & ATTR_MTIME && adfs_inode_is_stamped(inode)) {327 adfs_unix2adfs_time(inode, &attr->ia_mtime);328 adfs_adfs2unix_time(&attr->ia_mtime, inode);329 inode_set_mtime_to_ts(inode, attr->ia_mtime);330 }331 332 /*333 * FIXME: should we make these == to i_mtime since we don't334 * have the ability to represent them in our filesystem?335 */336 if (ia_valid & ATTR_ATIME)337 inode_set_atime_to_ts(inode, attr->ia_atime);338 if (ia_valid & ATTR_CTIME)339 inode_set_ctime_to_ts(inode, attr->ia_ctime);340 if (ia_valid & ATTR_MODE) {341 ADFS_I(inode)->attr = adfs_mode2atts(sb, inode, attr->ia_mode);342 inode->i_mode = adfs_atts2mode(sb, inode);343 }344 345 /*346 * FIXME: should we be marking this inode dirty even if347 * we don't have any metadata to write back?348 */349 if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE))350 mark_inode_dirty(inode);351out:352 return error;353}354 355/*356 * write an existing inode back to the directory, and therefore the disk.357 * The adfs-specific inode data has already been updated by358 * adfs_notify_change()359 */360int adfs_write_inode(struct inode *inode, struct writeback_control *wbc)361{362 struct super_block *sb = inode->i_sb;363 struct object_info obj;364 365 obj.indaddr = ADFS_I(inode)->indaddr;366 obj.name_len = 0;367 obj.parent_id = ADFS_I(inode)->parent_id;368 obj.loadaddr = ADFS_I(inode)->loadaddr;369 obj.execaddr = ADFS_I(inode)->execaddr;370 obj.attr = ADFS_I(inode)->attr;371 obj.size = inode->i_size;372 373 return adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL);374}375