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