/* * linux/fs/ufs/ufs_dir.c * * Copyright (C) 1996 * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu) * Laboratory for Computer Science Research Computing Facility * Rutgers, The State University of New Jersey * * swab support by Francois-Rene Rideau <fare@tunes.org> 19970406 * * 4.4BSD (FreeBSD) support added on February 1st 1998 by * Niels Kristian Bech Jensen <nkbj@image.dk> partially based * on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>. * * Migration to usage of "page cache" on May 2006 by * Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base. */ #include <linux/time.h> #include <linux/fs.h> #include <linux/swap.h> #include "ufs_fs.h" #include "ufs.h" #include "swab.h" #include "util.h" /* * NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure. * * len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller. */ static inline int ufs_match(struct super_block *sb, int len, const unsigned char *name, struct ufs_dir_entry *de) { if (len != ufs_get_de_namlen(sb, de)) return 0; if (!de->d_ino) return 0; return !memcmp(name, de->d_name, len); } static int ufs_commit_chunk(struct page *page, loff_t pos, unsigned len) { struct address_space *mapping = page->mapping; struct inode *dir = mapping->host; int err = 0; dir->i_version++; block_write_end(NULL, mapping, pos, len, len, page, NULL); if (pos+len > dir->i_size) { i_size_write(dir, pos+len); mark_inode_dirty(dir); } if (IS_DIRSYNC(dir)) err = write_one_page(page, 1); else unlock_page(page); return err; } static inline void ufs_put_page(struct page *page) { kunmap(page); put_page(page); } ino_t ufs_inode_by_name(struct inode *dir, const struct qstr *qstr) { ino_t res = 0; struct ufs_dir_entry *de; struct page *page; de = ufs_find_entry(dir, qstr, &page); if (de) { res = fs32_to_cpu(dir->i_sb, de->d_ino); ufs_put_page(page); } return res; } /* Releases the page */ void ufs_set_link(struct inode *dir, struct ufs_dir_entry *de, struct page *page, struct inode *inode, bool update_times) { loff_t pos = page_offset(page) + (char *) de - (char *) page_address(page); unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen); int err; lock_page(page); err = ufs_prepare_chunk(page, pos, len); BUG_ON(err); de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino); ufs_set_de_type(dir->i_sb, de, inode->i_mode); err = ufs_commit_chunk(page, pos, len); ufs_put_page(page); if (update_times) dir->i_mtime = dir->i_ctime = current_time(dir); mark_inode_dirty(dir); } static bool ufs_check_page(struct page *page) { struct inode *dir = page->mapping->host; struct super_block *sb = dir->i_sb; char *kaddr = page_address(page); unsigned offs, rec_len; unsigned limit = PAGE_SIZE; const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1; struct ufs_dir_entry *p; char *error; if ((dir->i_size >> PAGE_SHIFT) == page->index) { limit = dir->i_size & ~PAGE_MASK; if (limit & chunk_mask) goto Ebadsize; if (!limit) goto out; } for (offs = 0; offs <= limit - UFS_DIR_REC_LEN(1); offs += rec_len) { p = (struct ufs_dir_entry *)(kaddr + offs); rec_len = fs16_to_cpu(sb, p->d_reclen); if (rec_len < UFS_DIR_REC_LEN(1)) goto Eshort; if (rec_len & 3) goto Ealign; if (rec_len < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p))) goto Enamelen; if (((offs + rec_len - 1) ^ offs) & ~chunk_mask) goto Espan; if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg * UFS_SB(sb)->s_uspi->s_ncg)) goto Einumber; } if (offs != limit) goto Eend; out: SetPageChecked(page); return true; /* Too bad, we had an error */ Ebadsize: ufs_error(sb, "ufs_check_page", "size of directory #%lu is not a multiple of chunk size", dir->i_ino ); goto fail; Eshort: error = "rec_len is smaller than minimal"; goto bad_entry; Ealign: error = "unaligned directory entry"; goto bad_entry; Enamelen: error = "rec_len is too small for name_len"; goto bad_entry; Espan: error = "directory entry across blocks"; goto bad_entry; Einumber: error = "inode out of bounds"; bad_entry: ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - " "offset=%lu, rec_len=%d, name_len=%d", dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs, rec_len, ufs_get_de_namlen(sb, p)); goto fail; Eend: p = (struct ufs_dir_entry *)(kaddr + offs); ufs_error(sb, __func__, "entry in directory #%lu spans the page boundary" "offset=%lu", dir->i_ino, (page->index<<PAGE_SHIFT)+offs); fail: SetPageError(page); return false; } static struct page *ufs_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); if (unlikely(!PageChecked(page))) { if (PageError(page) || !ufs_check_page(page)) goto fail; } } return page; fail: ufs_put_page(page); return ERR_PTR(-EIO); } /* * Return the offset into page `page_nr' of the last valid * byte in that page, plus one. */ static unsigned ufs_last_byte(struct inode *inode, unsigned long page_nr) { unsigned last_byte = inode->i_size; last_byte -= page_nr << PAGE_SHIFT; if (last_byte > PAGE_SIZE) last_byte = PAGE_SIZE; return last_byte; } static inline struct ufs_dir_entry * ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p) { return (struct ufs_dir_entry *)((char *)p + fs16_to_cpu(sb, p->d_reclen)); } struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p) { struct page *page = ufs_get_page(dir, 0); struct ufs_dir_entry *de = NULL; if (!IS_ERR(page)) { de = ufs_next_entry(dir->i_sb, (struct ufs_dir_entry *)page_address(page)); *p = page; } return de; } /* * ufs_find_entry() * * finds an entry in the specified directory with the wanted name. It * returns the page in which the entry was found, and the entry itself * (as a parameter - res_dir). Page is returned mapped and unlocked. * Entry is guaranteed to be valid. */ struct ufs_dir_entry *ufs_find_entry(struct inode *dir, const struct qstr *qstr, struct page **res_page) { struct super_block *sb = dir->i_sb; const unsigned char *name = qstr->name; int namelen = qstr->len; unsigned reclen = UFS_DIR_REC_LEN(namelen); unsigned long start, n; unsigned long npages = dir_pages(dir); struct page *page = NULL; struct ufs_inode_info *ui = UFS_I(dir); struct ufs_dir_entry *de; UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen); if (npages == 0 || namelen > UFS_MAXNAMLEN) goto out; /* OFFSET_CACHE */ *res_page = NULL; start = ui->i_dir_start_lookup; if (start >= npages) start = 0; n = start; do { char *kaddr; page = ufs_get_page(dir, n); if (!IS_ERR(page)) { kaddr = page_address(page); de = (struct ufs_dir_entry *) kaddr; kaddr += ufs_last_byte(dir, n) - reclen; while ((char *) de <= kaddr) { if (ufs_match(sb, namelen, name, de)) goto found; de = ufs_next_entry(sb, de); } ufs_put_page(page); } if (++n >= npages) n = 0; } while (n != start); out: return NULL; found: *res_page = page; ui->i_dir_start_lookup = n; return de; } /* * Parent is locked. */ int ufs_add_link(struct dentry *dentry, struct inode *inode) { struct inode *dir = d_inode(dentry->d_parent); const unsigned char *name = dentry->d_name.name; int namelen = dentry->d_name.len; struct super_block *sb = dir->i_sb; unsigned reclen = UFS_DIR_REC_LEN(namelen); const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; unsigned short rec_len, name_len; struct page *page = NULL; struct ufs_dir_entry *de; unsigned long npages = dir_pages(dir); unsigned long n; char *kaddr; loff_t pos; int err; UFSD("ENTER, name %s, namelen %u\n", name, namelen); /* * We take care of directory expansion in the same loop. * This code plays outside i_size, so it locks the page * to protect that region. */ for (n = 0; n <= npages; n++) { char *dir_end; page = ufs_get_page(dir, n); err = PTR_ERR(page); if (IS_ERR(page)) goto out; lock_page(page); kaddr = page_address(page); dir_end = kaddr + ufs_last_byte(dir, n); de = (struct ufs_dir_entry *)kaddr; kaddr += PAGE_SIZE - reclen; while ((char *)de <= kaddr) { if ((char *)de == dir_end) { /* We hit i_size */ name_len = 0; rec_len = chunk_size; de->d_reclen = cpu_to_fs16(sb, chunk_size); de->d_ino = 0; goto got_it; } if (de->d_reclen == 0) { ufs_error(dir->i_sb, __func__, "zero-length directory entry"); err = -EIO; goto out_unlock; } err = -EEXIST; if (ufs_match(sb, namelen, name, de)) goto out_unlock; name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de)); rec_len = fs16_to_cpu(sb, de->d_reclen); if (!de->d_ino && rec_len >= reclen) goto got_it; if (rec_len >= name_len + reclen) goto got_it; de = (struct ufs_dir_entry *) ((char *) de + rec_len); } unlock_page(page); ufs_put_page(page); } BUG(); return -EINVAL; got_it: pos = page_offset(page) + (char*)de - (char*)page_address(page); err = ufs_prepare_chunk(page, pos, rec_len); if (err) goto out_unlock; if (de->d_ino) { struct ufs_dir_entry *de1 = (struct ufs_dir_entry *) ((char *) de + name_len); de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len); de->d_reclen = cpu_to_fs16(sb, name_len); de = de1; } ufs_set_de_namlen(sb, de, namelen); memcpy(de->d_name, name, namelen + 1); de->d_ino = cpu_to_fs32(sb, inode->i_ino); ufs_set_de_type(sb, de, inode->i_mode); err = ufs_commit_chunk(page, pos, rec_len); dir->i_mtime = dir->i_ctime = current_time(dir); mark_inode_dirty(dir); /* OFFSET_CACHE */ out_put: ufs_put_page(page); out: return err; out_unlock: unlock_page(page); goto out_put; } static inline unsigned ufs_validate_entry(struct super_block *sb, char *base, unsigned offset, unsigned mask) { struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset); struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask)); while ((char*)p < (char*)de) p = ufs_next_entry(sb, p); return (char *)p - base; } /* * This is blatantly stolen from ext2fs */ static int ufs_readdir(struct file *file, struct dir_context *ctx) { loff_t pos = ctx->pos; struct inode *inode = file_inode(file); struct super_block *sb = inode->i_sb; unsigned int offset = pos & ~PAGE_MASK; unsigned long n = pos >> PAGE_SHIFT; unsigned long npages = dir_pages(inode); unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); int need_revalidate = file->f_version != inode->i_version; unsigned flags = UFS_SB(sb)->s_flags; UFSD("BEGIN\n"); if (pos > inode->i_size - UFS_DIR_REC_LEN(1)) return 0; for ( ; n < npages; n++, offset = 0) { char *kaddr, *limit; struct ufs_dir_entry *de; struct page *page = ufs_get_page(inode, n); if (IS_ERR(page)) { ufs_error(sb, __func__, "bad page in #%lu", inode->i_ino); ctx->pos += PAGE_SIZE - offset; return -EIO; } kaddr = page_address(page); if (unlikely(need_revalidate)) { if (offset) { offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask); ctx->pos = (n<<PAGE_SHIFT) + offset; } file->f_version = inode->i_version; need_revalidate = 0; } de = (struct ufs_dir_entry *)(kaddr+offset); limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1); for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) { if (de->d_ino) { unsigned char d_type = DT_UNKNOWN; UFSD("filldir(%s,%u)\n", de->d_name, fs32_to_cpu(sb, de->d_ino)); UFSD("namlen %u\n", ufs_get_de_namlen(sb, de)); if ((flags & UFS_DE_MASK) == UFS_DE_44BSD) d_type = de->d_u.d_44.d_type; if (!dir_emit(ctx, de->d_name, ufs_get_de_namlen(sb, de), fs32_to_cpu(sb, de->d_ino), d_type)) { ufs_put_page(page); return 0; } } ctx->pos += fs16_to_cpu(sb, de->d_reclen); } ufs_put_page(page); } return 0; } /* * ufs_delete_entry deletes a directory entry by merging it with the * previous entry. */ int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir, struct page * page) { struct super_block *sb = inode->i_sb; char *kaddr = page_address(page); unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1); unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen); loff_t pos; struct ufs_dir_entry *pde = NULL; struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from); int err; UFSD("ENTER\n"); UFSD("ino %u, reclen %u, namlen %u, name %s\n", fs32_to_cpu(sb, de->d_ino), fs16_to_cpu(sb, de->d_reclen), ufs_get_de_namlen(sb, de), de->d_name); while ((char*)de < (char*)dir) { if (de->d_reclen == 0) { ufs_error(inode->i_sb, __func__, "zero-length directory entry"); err = -EIO; goto out; } pde = de; de = ufs_next_entry(sb, de); } if (pde) from = (char*)pde - (char*)page_address(page); pos = page_offset(page) + from; lock_page(page); err = ufs_prepare_chunk(page, pos, to - from); BUG_ON(err); if (pde) pde->d_reclen = cpu_to_fs16(sb, to - from); dir->d_ino = 0; err = ufs_commit_chunk(page, pos, to - from); inode->i_ctime = inode->i_mtime = current_time(inode); mark_inode_dirty(inode); out: ufs_put_page(page); UFSD("EXIT\n"); return err; } int ufs_make_empty(struct inode * inode, struct inode *dir) { struct super_block * sb = dir->i_sb; struct address_space *mapping = inode->i_mapping; struct page *page = grab_cache_page(mapping, 0); const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize; struct ufs_dir_entry * de; char *base; int err; if (!page) return -ENOMEM; err = ufs_prepare_chunk(page, 0, chunk_size); if (err) { unlock_page(page); goto fail; } kmap(page); base = (char*)page_address(page); memset(base, 0, PAGE_SIZE); de = (struct ufs_dir_entry *) base; de->d_ino = cpu_to_fs32(sb, inode->i_ino); ufs_set_de_type(sb, de, inode->i_mode); ufs_set_de_namlen(sb, de, 1); de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1)); strcpy (de->d_name, "."); de = (struct ufs_dir_entry *) ((char *)de + fs16_to_cpu(sb, de->d_reclen)); de->d_ino = cpu_to_fs32(sb, dir->i_ino); ufs_set_de_type(sb, de, dir->i_mode); de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1)); ufs_set_de_namlen(sb, de, 2); strcpy (de->d_name, ".."); kunmap(page); err = ufs_commit_chunk(page, 0, chunk_size); fail: put_page(page); return err; } /* * routine to check that the specified directory is empty (for rmdir) */ int ufs_empty_dir(struct inode * inode) { struct super_block *sb = inode->i_sb; struct page *page = NULL; unsigned long i, npages = dir_pages(inode); for (i = 0; i < npages; i++) { char *kaddr; struct ufs_dir_entry *de; page = ufs_get_page(inode, i); if (IS_ERR(page)) continue; kaddr = page_address(page); de = (struct ufs_dir_entry *)kaddr; kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1); while ((char *)de <= kaddr) { if (de->d_reclen == 0) { ufs_error(inode->i_sb, __func__, "zero-length directory entry: " "kaddr=%p, de=%p\n", kaddr, de); goto not_empty; } if (de->d_ino) { u16 namelen=ufs_get_de_namlen(sb, de); /* check for . and .. */ if (de->d_name[0] != '.') goto not_empty; if (namelen > 2) goto not_empty; if (namelen < 2) { if (inode->i_ino != fs32_to_cpu(sb, de->d_ino)) goto not_empty; } else if (de->d_name[1] != '.') goto not_empty; } de = ufs_next_entry(sb, de); } ufs_put_page(page); } return 1; not_empty: ufs_put_page(page); return 0; } const struct file_operations ufs_dir_operations = { .read = generic_read_dir, .iterate_shared = ufs_readdir, .fsync = generic_file_fsync, .llseek = generic_file_llseek, };