diff options
Diffstat (limited to 'kernel/fs/qnx6/dir.c')
| -rw-r--r-- | kernel/fs/qnx6/dir.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/kernel/fs/qnx6/dir.c b/kernel/fs/qnx6/dir.c new file mode 100644 index 000000000..8d64bb536 --- /dev/null +++ b/kernel/fs/qnx6/dir.c @@ -0,0 +1,286 @@ +/* + * 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; +} + +static inline unsigned long dir_pages(struct inode *inode) +{ + return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; +} + +static unsigned last_entry(struct inode *inode, unsigned long page_nr) +{ + unsigned long last_byte = inode->i_size; + last_byte -= page_nr << PAGE_CACHE_SHIFT; + if (last_byte > PAGE_CACHE_SIZE) + last_byte = PAGE_CACHE_SIZE; + 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 */ + u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */ + /* within page */ + u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK; + 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, + struct dir_context *ctx, + unsigned de_inode) +{ + 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 */ + pr_err("invalid direntry size (%i).\n", de->de_size); + return 0; + } + lf = qnx6_longname(s, de, &page); + if (IS_ERR(lf)) { + pr_err("Error reading longname\n"); + return 0; + } + + lf_size = fs16_to_cpu(sbi, lf->lf_size); + + if (lf_size > QNX6_LONG_NAME_MAX) { + pr_debug("file %s\n", lf->lf_fname); + pr_err("Filename too long (%i)\n", lf_size); + 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)) + pr_info("long filename checksum error.\n"); + + pr_debug("qnx6_readdir:%.*s inode:%u\n", + lf_size, lf->lf_fname, de_inode); + if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) { + qnx6_put_page(page); + return 0; + } + + qnx6_put_page(page); + /* success */ + return 1; +} + +static int qnx6_readdir(struct file *file, struct dir_context *ctx) +{ + struct inode *inode = file_inode(file); + struct super_block *s = inode->i_sb; + struct qnx6_sb_info *sbi = QNX6_SB(s); + loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1); + unsigned long npages = dir_pages(inode); + unsigned long n = pos >> PAGE_CACHE_SHIFT; + unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE; + bool done = false; + + ctx->pos = pos; + if (ctx->pos >= inode->i_size) + 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)) { + pr_err("%s(): read failed\n", __func__); + ctx->pos = (n + 1) << PAGE_CACHE_SHIFT; + return PTR_ERR(page); + } + de = ((struct qnx6_dir_entry *)page_address(page)) + start; + for (; i < limit; i++, de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) { + 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, + ctx, no_inode)) { + done = true; + break; + } + } else { + pr_debug("%s():%.*s inode:%u\n", + __func__, size, de->de_fname, + no_inode); + if (!dir_emit(ctx, de->de_fname, size, + no_inode, DT_UNKNOWN)) { + done = true; + break; + } + } + } + qnx6_put_page(page); + } + 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 + pr_err("undefined filename size in inode.\n"); + } + 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, + .iterate = qnx6_readdir, + .fsync = generic_file_fsync, +}; + +const struct inode_operations qnx6_dir_inode_operations = { + .lookup = qnx6_lookup, +}; 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