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287 lines
7.1 KiB
287 lines
7.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/fs/adfs/dir_fplus.c |
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* |
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* Copyright (C) 1997-1999 Russell King |
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*/ |
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#include "adfs.h" |
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#include "dir_fplus.h" |
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/* Return the byte offset to directory entry pos */ |
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static unsigned int adfs_fplus_offset(const struct adfs_bigdirheader *h, |
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unsigned int pos) |
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{ |
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return offsetof(struct adfs_bigdirheader, bigdirname) + |
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ALIGN(le32_to_cpu(h->bigdirnamelen), 4) + |
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pos * sizeof(struct adfs_bigdirentry); |
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} |
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static int adfs_fplus_validate_header(const struct adfs_bigdirheader *h) |
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{ |
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unsigned int size = le32_to_cpu(h->bigdirsize); |
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unsigned int len; |
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if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 || |
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h->bigdirversion[2] != 0 || |
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h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME) || |
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!size || size & 2047 || size > SZ_4M) |
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return -EIO; |
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size -= sizeof(struct adfs_bigdirtail) + |
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offsetof(struct adfs_bigdirheader, bigdirname); |
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/* Check that bigdirnamelen fits within the directory */ |
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len = ALIGN(le32_to_cpu(h->bigdirnamelen), 4); |
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if (len > size) |
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return -EIO; |
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size -= len; |
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/* Check that bigdirnamesize fits within the directory */ |
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len = le32_to_cpu(h->bigdirnamesize); |
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if (len > size) |
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return -EIO; |
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size -= len; |
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/* |
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* Avoid division, we know that absolute maximum number of entries |
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* can not be so large to cause overflow of the multiplication below. |
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*/ |
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len = le32_to_cpu(h->bigdirentries); |
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if (len > SZ_4M / sizeof(struct adfs_bigdirentry) || |
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len * sizeof(struct adfs_bigdirentry) > size) |
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return -EIO; |
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return 0; |
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} |
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static int adfs_fplus_validate_tail(const struct adfs_bigdirheader *h, |
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const struct adfs_bigdirtail *t) |
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{ |
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if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) || |
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t->bigdirendmasseq != h->startmasseq || |
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t->reserved[0] != 0 || t->reserved[1] != 0) |
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return -EIO; |
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return 0; |
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} |
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static u8 adfs_fplus_checkbyte(struct adfs_dir *dir) |
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{ |
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struct adfs_bigdirheader *h = dir->bighead; |
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struct adfs_bigdirtail *t = dir->bigtail; |
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unsigned int end, bs, bi, i; |
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__le32 *bp; |
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u32 dircheck; |
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end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)) + |
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le32_to_cpu(h->bigdirnamesize); |
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/* Accumulate the contents of the header, entries and names */ |
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for (dircheck = 0, bi = 0; end; bi++) { |
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bp = (void *)dir->bhs[bi]->b_data; |
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bs = dir->bhs[bi]->b_size; |
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if (bs > end) |
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bs = end; |
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for (i = 0; i < bs; i += sizeof(u32)) |
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dircheck = ror32(dircheck, 13) ^ le32_to_cpup(bp++); |
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end -= bs; |
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} |
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/* Accumulate the contents of the tail except for the check byte */ |
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dircheck = ror32(dircheck, 13) ^ le32_to_cpu(t->bigdirendname); |
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dircheck = ror32(dircheck, 13) ^ t->bigdirendmasseq; |
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dircheck = ror32(dircheck, 13) ^ t->reserved[0]; |
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dircheck = ror32(dircheck, 13) ^ t->reserved[1]; |
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return dircheck ^ dircheck >> 8 ^ dircheck >> 16 ^ dircheck >> 24; |
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} |
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static int adfs_fplus_read(struct super_block *sb, u32 indaddr, |
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unsigned int size, struct adfs_dir *dir) |
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{ |
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struct adfs_bigdirheader *h; |
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struct adfs_bigdirtail *t; |
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unsigned int dirsize; |
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int ret; |
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/* Read first buffer */ |
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ret = adfs_dir_read_buffers(sb, indaddr, sb->s_blocksize, dir); |
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if (ret) |
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return ret; |
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dir->bighead = h = (void *)dir->bhs[0]->b_data; |
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ret = adfs_fplus_validate_header(h); |
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if (ret) { |
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adfs_error(sb, "dir %06x has malformed header", indaddr); |
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goto out; |
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} |
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dirsize = le32_to_cpu(h->bigdirsize); |
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if (size && dirsize != size) { |
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adfs_msg(sb, KERN_WARNING, |
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"dir %06x header size %X does not match directory size %X", |
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indaddr, dirsize, size); |
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} |
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/* Read remaining buffers */ |
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ret = adfs_dir_read_buffers(sb, indaddr, dirsize, dir); |
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if (ret) |
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return ret; |
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dir->bigtail = t = (struct adfs_bigdirtail *) |
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(dir->bhs[dir->nr_buffers - 1]->b_data + (sb->s_blocksize - 8)); |
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ret = adfs_fplus_validate_tail(h, t); |
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if (ret) { |
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adfs_error(sb, "dir %06x has malformed tail", indaddr); |
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goto out; |
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} |
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if (adfs_fplus_checkbyte(dir) != t->bigdircheckbyte) { |
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adfs_error(sb, "dir %06x checkbyte mismatch\n", indaddr); |
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goto out; |
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} |
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dir->parent_id = le32_to_cpu(h->bigdirparent); |
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return 0; |
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out: |
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adfs_dir_relse(dir); |
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return ret; |
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} |
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static int |
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adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos) |
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{ |
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int ret = -ENOENT; |
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if (fpos <= le32_to_cpu(dir->bighead->bigdirentries)) { |
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dir->pos = fpos; |
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ret = 0; |
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} |
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return ret; |
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} |
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static int |
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adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj) |
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{ |
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struct adfs_bigdirheader *h = dir->bighead; |
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struct adfs_bigdirentry bde; |
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unsigned int offset; |
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int ret; |
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if (dir->pos >= le32_to_cpu(h->bigdirentries)) |
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return -ENOENT; |
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offset = adfs_fplus_offset(h, dir->pos); |
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ret = adfs_dir_copyfrom(&bde, dir, offset, |
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sizeof(struct adfs_bigdirentry)); |
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if (ret) |
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return ret; |
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obj->loadaddr = le32_to_cpu(bde.bigdirload); |
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obj->execaddr = le32_to_cpu(bde.bigdirexec); |
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obj->size = le32_to_cpu(bde.bigdirlen); |
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obj->indaddr = le32_to_cpu(bde.bigdirindaddr); |
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obj->attr = le32_to_cpu(bde.bigdirattr); |
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obj->name_len = le32_to_cpu(bde.bigdirobnamelen); |
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offset = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)); |
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offset += le32_to_cpu(bde.bigdirobnameptr); |
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ret = adfs_dir_copyfrom(obj->name, dir, offset, obj->name_len); |
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if (ret) |
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return ret; |
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adfs_object_fixup(dir, obj); |
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dir->pos += 1; |
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return 0; |
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} |
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static int adfs_fplus_iterate(struct adfs_dir *dir, struct dir_context *ctx) |
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{ |
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struct object_info obj; |
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if ((ctx->pos - 2) >> 32) |
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return 0; |
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if (adfs_fplus_setpos(dir, ctx->pos - 2)) |
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return 0; |
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while (!adfs_fplus_getnext(dir, &obj)) { |
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if (!dir_emit(ctx, obj.name, obj.name_len, |
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obj.indaddr, DT_UNKNOWN)) |
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break; |
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ctx->pos++; |
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} |
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return 0; |
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} |
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static int adfs_fplus_update(struct adfs_dir *dir, struct object_info *obj) |
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{ |
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struct adfs_bigdirheader *h = dir->bighead; |
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struct adfs_bigdirentry bde; |
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int offset, end, ret; |
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offset = adfs_fplus_offset(h, 0) - sizeof(bde); |
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end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)); |
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do { |
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offset += sizeof(bde); |
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if (offset >= end) { |
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adfs_error(dir->sb, "unable to locate entry to update"); |
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return -ENOENT; |
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} |
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ret = adfs_dir_copyfrom(&bde, dir, offset, sizeof(bde)); |
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if (ret) { |
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adfs_error(dir->sb, "error reading directory entry"); |
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return -ENOENT; |
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} |
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} while (le32_to_cpu(bde.bigdirindaddr) != obj->indaddr); |
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bde.bigdirload = cpu_to_le32(obj->loadaddr); |
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bde.bigdirexec = cpu_to_le32(obj->execaddr); |
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bde.bigdirlen = cpu_to_le32(obj->size); |
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bde.bigdirindaddr = cpu_to_le32(obj->indaddr); |
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bde.bigdirattr = cpu_to_le32(obj->attr); |
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return adfs_dir_copyto(dir, offset, &bde, sizeof(bde)); |
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} |
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static int adfs_fplus_commit(struct adfs_dir *dir) |
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{ |
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int ret; |
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/* Increment directory sequence number */ |
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dir->bighead->startmasseq += 1; |
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dir->bigtail->bigdirendmasseq += 1; |
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/* Update directory check byte */ |
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dir->bigtail->bigdircheckbyte = adfs_fplus_checkbyte(dir); |
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/* Make sure the directory still validates correctly */ |
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ret = adfs_fplus_validate_header(dir->bighead); |
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if (ret == 0) |
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ret = adfs_fplus_validate_tail(dir->bighead, dir->bigtail); |
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return ret; |
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} |
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const struct adfs_dir_ops adfs_fplus_dir_ops = { |
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.read = adfs_fplus_read, |
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.iterate = adfs_fplus_iterate, |
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.setpos = adfs_fplus_setpos, |
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.getnext = adfs_fplus_getnext, |
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.update = adfs_fplus_update, |
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.commit = adfs_fplus_commit, |
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};
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