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fs/qnx6/dir.c
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// SPDX-License-Identifier: GPL-2.0 |
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/* * QNX6 file system, Linux implementation. * * Version : 1.0.0 * * History : * * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release. * 16-02-2012 pagemap extension by Al Viro * */ #include "qnx6.h" static unsigned qnx6_lfile_checksum(char *name, unsigned size) { unsigned crc = 0; char *end = name + size; while (name < end) { crc = ((crc >> 1) + *(name++)) ^ ((crc & 0x00000001) ? 0x80000000 : 0); } return crc; } static struct page *qnx6_get_page(struct inode *dir, unsigned long n) { struct address_space *mapping = dir->i_mapping; struct page *page = read_mapping_page(mapping, n, NULL); if (!IS_ERR(page)) kmap(page); return page; } |
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static unsigned last_entry(struct inode *inode, unsigned long page_nr) { unsigned long last_byte = inode->i_size; |
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last_byte -= page_nr << PAGE_SHIFT; if (last_byte > PAGE_SIZE) last_byte = PAGE_SIZE; |
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return last_byte / QNX6_DIR_ENTRY_SIZE; } static struct qnx6_long_filename *qnx6_longname(struct super_block *sb, struct qnx6_long_dir_entry *de, struct page **p) { struct qnx6_sb_info *sbi = QNX6_SB(sb); u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */ |
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u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */ |
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/* within page */ |
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u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_MASK; |
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struct address_space *mapping = sbi->longfile->i_mapping; struct page *page = read_mapping_page(mapping, n, NULL); if (IS_ERR(page)) return ERR_CAST(page); kmap(*p = page); return (struct qnx6_long_filename *)(page_address(page) + offs); } static int qnx6_dir_longfilename(struct inode *inode, struct qnx6_long_dir_entry *de, |
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struct dir_context *ctx, unsigned de_inode) |
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{ struct qnx6_long_filename *lf; struct super_block *s = inode->i_sb; struct qnx6_sb_info *sbi = QNX6_SB(s); struct page *page; int lf_size; if (de->de_size != 0xff) { /* error - long filename entries always have size 0xff in direntry */ |
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pr_err("invalid direntry size (%i). ", de->de_size); |
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return 0; } lf = qnx6_longname(s, de, &page); if (IS_ERR(lf)) { |
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pr_err("Error reading longname "); |
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return 0; } lf_size = fs16_to_cpu(sbi, lf->lf_size); if (lf_size > QNX6_LONG_NAME_MAX) { |
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pr_debug("file %s ", lf->lf_fname); |
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pr_err("Filename too long (%i) ", lf_size); |
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qnx6_put_page(page); return 0; } /* calc & validate longfilename checksum mmi 3g filesystem does not have that checksum */ if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) != qnx6_lfile_checksum(lf->lf_fname, lf_size)) |
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pr_info("long filename checksum error. "); |
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pr_debug("qnx6_readdir:%.*s inode:%u ", lf_size, lf->lf_fname, de_inode); |
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if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) { |
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qnx6_put_page(page); return 0; } qnx6_put_page(page); /* success */ return 1; } |
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static int qnx6_readdir(struct file *file, struct dir_context *ctx) |
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{ |
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struct inode *inode = file_inode(file); |
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struct super_block *s = inode->i_sb; struct qnx6_sb_info *sbi = QNX6_SB(s); |
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loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1); |
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unsigned long npages = dir_pages(inode); |
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unsigned long n = pos >> PAGE_SHIFT; unsigned start = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE; |
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bool done = false; |
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ctx->pos = pos; if (ctx->pos >= inode->i_size) |
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return 0; for ( ; !done && n < npages; n++, start = 0) { struct page *page = qnx6_get_page(inode, n); int limit = last_entry(inode, n); struct qnx6_dir_entry *de; int i = start; if (IS_ERR(page)) { |
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pr_err("%s(): read failed ", __func__); |
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ctx->pos = (n + 1) << PAGE_SHIFT; |
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return PTR_ERR(page); } de = ((struct qnx6_dir_entry *)page_address(page)) + start; |
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for (; i < limit; i++, de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) { |
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int size = de->de_size; u32 no_inode = fs32_to_cpu(sbi, de->de_inode); if (!no_inode || !size) continue; if (size > QNX6_SHORT_NAME_MAX) { /* long filename detected get the filename from long filename structure / block */ if (!qnx6_dir_longfilename(inode, (struct qnx6_long_dir_entry *)de, |
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ctx, no_inode)) { |
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done = true; break; } } else { |
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pr_debug("%s():%.*s inode:%u ", __func__, size, de->de_fname, no_inode); |
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if (!dir_emit(ctx, de->de_fname, size, no_inode, DT_UNKNOWN)) { |
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done = true; break; } } } qnx6_put_page(page); } |
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return 0; } /* * check if the long filename is correct. */ static unsigned qnx6_long_match(int len, const char *name, struct qnx6_long_dir_entry *de, struct inode *dir) { struct super_block *s = dir->i_sb; struct qnx6_sb_info *sbi = QNX6_SB(s); struct page *page; int thislen; struct qnx6_long_filename *lf = qnx6_longname(s, de, &page); if (IS_ERR(lf)) return 0; thislen = fs16_to_cpu(sbi, lf->lf_size); if (len != thislen) { qnx6_put_page(page); return 0; } if (memcmp(name, lf->lf_fname, len) == 0) { qnx6_put_page(page); return fs32_to_cpu(sbi, de->de_inode); } qnx6_put_page(page); return 0; } /* * check if the filename is correct. */ static unsigned qnx6_match(struct super_block *s, int len, const char *name, struct qnx6_dir_entry *de) { struct qnx6_sb_info *sbi = QNX6_SB(s); if (memcmp(name, de->de_fname, len) == 0) return fs32_to_cpu(sbi, de->de_inode); return 0; } unsigned qnx6_find_entry(int len, struct inode *dir, const char *name, struct page **res_page) { struct super_block *s = dir->i_sb; struct qnx6_inode_info *ei = QNX6_I(dir); struct page *page = NULL; unsigned long start, n; unsigned long npages = dir_pages(dir); unsigned ino; struct qnx6_dir_entry *de; struct qnx6_long_dir_entry *lde; *res_page = NULL; if (npages == 0) return 0; start = ei->i_dir_start_lookup; if (start >= npages) start = 0; n = start; do { page = qnx6_get_page(dir, n); if (!IS_ERR(page)) { int limit = last_entry(dir, n); int i; de = (struct qnx6_dir_entry *)page_address(page); for (i = 0; i < limit; i++, de++) { if (len <= QNX6_SHORT_NAME_MAX) { /* short filename */ if (len != de->de_size) continue; ino = qnx6_match(s, len, name, de); if (ino) goto found; } else if (de->de_size == 0xff) { /* deal with long filename */ lde = (struct qnx6_long_dir_entry *)de; ino = qnx6_long_match(len, name, lde, dir); if (ino) goto found; } else |
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pr_err("undefined filename size in inode. "); |
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} qnx6_put_page(page); } if (++n >= npages) n = 0; } while (n != start); return 0; found: *res_page = page; ei->i_dir_start_lookup = n; return ino; } const struct file_operations qnx6_dir_operations = { .llseek = generic_file_llseek, .read = generic_read_dir, |
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.iterate_shared = qnx6_readdir, |
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.fsync = generic_file_fsync, }; const struct inode_operations qnx6_dir_inode_operations = { .lookup = qnx6_lookup, }; |