diff options
| -rw-r--r-- | fs/nilfs2/dir.c | 711 |
1 files changed, 711 insertions, 0 deletions
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c new file mode 100644 index 000000000000..1b7e6ddabbeb --- /dev/null +++ b/fs/nilfs2/dir.c @@ -0,0 +1,711 @@ +/* + * dir.c - NILFS directory entry operations + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Modified for NILFS by Amagai Yoshiji <amagai@osrg.net> + */ +/* + * linux/fs/ext2/dir.c + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/fs/minix/dir.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * ext2 directory handling functions + * + * Big-endian to little-endian byte-swapping/bitmaps by + * David S. Miller (davem@caip.rutgers.edu), 1995 + * + * All code that works with directory layout had been switched to pagecache + * and moved here. AV + */ + +#include <linux/pagemap.h> +#include <linux/smp_lock.h> +#include "nilfs.h" +#include "page.h" + +/* + * nilfs uses block-sized chunks. Arguably, sector-sized ones would be + * more robust, but we have what we have + */ +static inline unsigned nilfs_chunk_size(struct inode *inode) +{ + return inode->i_sb->s_blocksize; +} + +static inline void nilfs_put_page(struct page *page) +{ + kunmap(page); + page_cache_release(page); +} + +static inline unsigned long dir_pages(struct inode *inode) +{ + return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; +} + +/* + * Return the offset into page `page_nr' of the last valid + * byte in that page, plus one. + */ +static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr) +{ + unsigned 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; +} + +static int nilfs_prepare_chunk_uninterruptible(struct page *page, + struct address_space *mapping, + unsigned from, unsigned to) +{ + loff_t pos = page_offset(page) + from; + return block_write_begin(NULL, mapping, pos, to - from, + AOP_FLAG_UNINTERRUPTIBLE, &page, + NULL, nilfs_get_block); +} + +static int nilfs_prepare_chunk(struct page *page, + struct address_space *mapping, + unsigned from, unsigned to) +{ + loff_t pos = page_offset(page) + from; + return block_write_begin(NULL, mapping, pos, to - from, 0, &page, + NULL, nilfs_get_block); +} + +static int nilfs_commit_chunk(struct page *page, + struct address_space *mapping, + unsigned from, unsigned to) +{ + struct inode *dir = mapping->host; + struct nilfs_sb_info *sbi = NILFS_SB(dir->i_sb); + loff_t pos = page_offset(page) + from; + unsigned len = to - from; + unsigned nr_dirty, copied; + int err; + + nr_dirty = nilfs_page_count_clean_buffers(page, from, to); + copied = block_write_end(NULL, mapping, pos, len, len, page, NULL); + if (pos + copied > dir->i_size) { + i_size_write(dir, pos + copied); + mark_inode_dirty(dir); + } + if (IS_DIRSYNC(dir)) + nilfs_set_transaction_flag(NILFS_TI_SYNC); + err = nilfs_set_file_dirty(sbi, dir, nr_dirty); + unlock_page(page); + return err; +} + +static void nilfs_check_page(struct page *page) +{ + struct inode *dir = page->mapping->host; + struct super_block *sb = dir->i_sb; + unsigned chunk_size = nilfs_chunk_size(dir); + char *kaddr = page_address(page); + unsigned offs, rec_len; + unsigned limit = PAGE_CACHE_SIZE; + struct nilfs_dir_entry *p; + char *error; + + if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { + limit = dir->i_size & ~PAGE_CACHE_MASK; + if (limit & (chunk_size - 1)) + goto Ebadsize; + if (!limit) + goto out; + } + for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) { + p = (struct nilfs_dir_entry *)(kaddr + offs); + rec_len = le16_to_cpu(p->rec_len); + + if (rec_len < NILFS_DIR_REC_LEN(1)) + goto Eshort; + if (rec_len & 3) + goto Ealign; + if (rec_len < NILFS_DIR_REC_LEN(p->name_len)) + goto Enamelen; + if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) + goto Espan; + } + if (offs != limit) + goto Eend; +out: + SetPageChecked(page); + return; + + /* Too bad, we had an error */ + +Ebadsize: + nilfs_error(sb, "nilfs_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"; +bad_entry: + nilfs_error(sb, "nilfs_check_page", "bad entry in directory #%lu: %s - " + "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", + dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, + (unsigned long) le64_to_cpu(p->inode), + rec_len, p->name_len); + goto fail; +Eend: + p = (struct nilfs_dir_entry *)(kaddr + offs); + nilfs_error(sb, "nilfs_check_page", + "entry in directory #%lu spans the page boundary" + "offset=%lu, inode=%lu", + dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs, + (unsigned long) le64_to_cpu(p->inode)); +fail: + SetPageChecked(page); + SetPageError(page); +} + +static struct page *nilfs_get_page(struct inode *dir, unsigned long n) +{ + struct address_space *mapping = dir->i_mapping; + struct page *page = read_cache_page(mapping, n, + (filler_t *)mapping->a_ops->readpage, NULL); + if (!IS_ERR(page)) { + wait_on_page_locked(page); + kmap(page); + if (!PageUptodate(page)) + goto fail; + if (!PageChecked(page)) + nilfs_check_page(page); + if (PageError(page)) + goto fail; + } + return page; + +fail: + nilfs_put_page(page); + return ERR_PTR(-EIO); +} + +/* + * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure. + * + * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller. + */ +static int +nilfs_match(int len, const char * const name, struct nilfs_dir_entry *de) +{ + if (len != de->name_len) + return 0; + if (!de->inode) + return 0; + return !memcmp(name, de->name, len); +} + +/* + * p is at least 6 bytes before the end of page + */ +static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p) +{ + return (struct nilfs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len)); +} + +static unsigned char +nilfs_filetype_table[NILFS_FT_MAX] = { + [NILFS_FT_UNKNOWN] = DT_UNKNOWN, + [NILFS_FT_REG_FILE] = DT_REG, + [NILFS_FT_DIR] = DT_DIR, + [NILFS_FT_CHRDEV] = DT_CHR, + [NILFS_FT_BLKDEV] = DT_BLK, + [NILFS_FT_FIFO] = DT_FIFO, + [NILFS_FT_SOCK] = DT_SOCK, + [NILFS_FT_SYMLINK] = DT_LNK, +}; + +#define S_SHIFT 12 +static unsigned char +nilfs_type_by_mode[S_IFMT >> S_SHIFT] = { + [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE, + [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR, + [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV, + [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV, + [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO, + [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK, + [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK, +}; + +static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode) +{ + mode_t mode = inode->i_mode; + + de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; +} + +static int nilfs_readdir(struct file *filp, void *dirent, filldir_t filldir) +{ + loff_t pos = filp->f_pos; + struct inode *inode = filp->f_dentry->d_inode; + struct super_block *sb = inode->i_sb; + unsigned int offset = pos & ~PAGE_CACHE_MASK; + unsigned long n = pos >> PAGE_CACHE_SHIFT; + unsigned long npages = dir_pages(inode); +/* unsigned chunk_mask = ~(nilfs_chunk_size(inode)-1); */ + unsigned char *types = NULL; + int ret; + + if (pos > inode->i_size - NILFS_DIR_REC_LEN(1)) + goto success; + + types = nilfs_filetype_table; + + for ( ; n < npages; n++, offset = 0) { + char *kaddr, *limit; + struct nilfs_dir_entry *de; + struct page *page = nilfs_get_page(inode, n); + + if (IS_ERR(page)) { + nilfs_error(sb, __func__, "bad page in #%lu", + inode->i_ino); + filp->f_pos += PAGE_CACHE_SIZE - offset; + ret = -EIO; + goto done; + } + kaddr = page_address(page); + de = (struct nilfs_dir_entry *)(kaddr + offset); + limit = kaddr + nilfs_last_byte(inode, n) - + NILFS_DIR_REC_LEN(1); + for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) { + if (de->rec_len == 0) { + nilfs_error(sb, __func__, + "zero-length directory entry"); + ret = -EIO; + nilfs_put_page(page); + goto done; + } + if (de->inode) { + int over; + unsigned char d_type = DT_UNKNOWN; + + if (types && de->file_type < NILFS_FT_MAX) + d_type = types[de->file_type]; + + offset = (char *)de - kaddr; + over = filldir(dirent, de->name, de->name_len, + (n<<PAGE_CACHE_SHIFT) | offset, + le64_to_cpu(de->inode), d_type); + if (over) { + nilfs_put_page(page); + goto success; + } + } + filp->f_pos += le16_to_cpu(de->rec_len); + } + nilfs_put_page(page); + } + +success: + ret = 0; +done: + return ret; +} + +/* + * nilfs_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 nilfs_dir_entry * +nilfs_find_entry(struct inode *dir, struct dentry *dentry, + struct page **res_page) +{ + const char *name = dentry->d_name.name; + int namelen = dentry->d_name.len; + unsigned reclen = NILFS_DIR_REC_LEN(namelen); + unsigned long start, n; + unsigned long npages = dir_pages(dir); + struct page *page = NULL; + struct nilfs_inode_info *ei = NILFS_I(dir); + struct nilfs_dir_entry *de; + + if (npages == 0) + goto out; + + /* OFFSET_CACHE */ + *res_page = NULL; + + start = ei->i_dir_start_lookup; + if (start >= npages) + start = 0; + n = start; + do { + char *kaddr; + page = nilfs_get_page(dir, n); + if (!IS_ERR(page)) { + kaddr = page_address(page); + de = (struct nilfs_dir_entry *)kaddr; + kaddr += nilfs_last_byte(dir, n) - reclen; + while ((char *) de <= kaddr) { + if (de->rec_len == 0) { + nilfs_error(dir->i_sb, __func__, + "zero-length directory entry"); + nilfs_put_page(page); + goto out; + } + if (nilfs_match(namelen, name, de)) + goto found; + de = nilfs_next_entry(de); + } + nilfs_put_page(page); + } + if (++n >= npages) + n = 0; + /* next page is past the blocks we've got */ + if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) { + nilfs_error(dir->i_sb, __func__, + "dir %lu size %lld exceeds block cout %llu", + dir->i_ino, dir->i_size, + (unsigned long long)dir->i_blocks); + goto out; + } + } while (n != start); +out: + return NULL; + +found: + *res_page = page; + ei->i_dir_start_lookup = n; + return de; +} + +struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p) +{ + struct page *page = nilfs_get_page(dir, 0); + struct nilfs_dir_entry *de = NULL; + + if (!IS_ERR(page)) { + de = nilfs_next_entry( + (struct nilfs_dir_entry *)page_address(page)); + *p = page; + } + return de; +} + +ino_t nilfs_inode_by_name(struct inode *dir, struct dentry *dentry) +{ + ino_t res = 0; + struct nilfs_dir_entry *de; + struct page *page; + + de = nilfs_find_entry(dir, dentry, &page); + if (de) { + res = le64_to_cpu(de->inode); + kunmap(page); + page_cache_release(page); + } + return res; +} + +/* Releases the page */ +void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, + struct page *page, struct inode *inode) +{ + unsigned from = (char *) de - (char *) page_address(page); + unsigned to = from + le16_to_cpu(de->rec_len); + struct address_space *mapping = page->mapping; + int err; + + lock_page(page); + err = nilfs_prepare_chunk_uninterruptible(page, mapping, from, to); + BUG_ON(err); + de->inode = cpu_to_le64(inode->i_ino); + nilfs_set_de_type(de, inode); + err = nilfs_commit_chunk(page, mapping, from, to); + nilfs_put_page(page); + dir->i_mtime = dir->i_ctime = CURRENT_TIME; +/* NILFS_I(dir)->i_flags &= ~NILFS_BTREE_FL; */ + mark_inode_dirty(dir); +} + +/* + * Parent is locked. + */ +int nilfs_add_link(struct dentry *dentry, struct inode *inode) +{ + struct inode *dir = dentry->d_parent->d_inode; + const char *name = dentry->d_name.name; + int namelen = dentry->d_name.len; + unsigned chunk_size = nilfs_chunk_size(dir); + unsigned reclen = NILFS_DIR_REC_LEN(namelen); + unsigned short rec_len, name_len; + struct page *page = NULL; + struct nilfs_dir_entry *de; + unsigned long npages = dir_pages(dir); + unsigned long n; + char *kaddr; + unsigned from, to; + int err; + + /* + * 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 = nilfs_get_page(dir, n); + err = PTR_ERR(page); + if (IS_ERR(page)) + goto out; + lock_page(page); + kaddr = page_address(page); + dir_end = kaddr + nilfs_last_byte(dir, n); + de = (struct nilfs_dir_entry *)kaddr; + kaddr += PAGE_CACHE_SIZE - reclen; + while ((char *)de <= kaddr) { + if ((char *)de == dir_end) { + /* We hit i_size */ + name_len = 0; + rec_len = chunk_size; + de->rec_len = cpu_to_le16(chunk_size); + de->inode = 0; + goto got_it; + } + if (de->rec_len == 0) { + nilfs_error(dir->i_sb, __func__, + "zero-length directory entry"); + err = -EIO; + goto out_unlock; + } + err = -EEXIST; + if (nilfs_match(namelen, name, de)) + goto out_unlock; + name_len = NILFS_DIR_REC_LEN(de->name_len); + rec_len = le16_to_cpu(de->rec_len); + if (!de->inode && rec_len >= reclen) + goto got_it; + if (rec_len >= name_len + reclen) + goto got_it; + de = (struct nilfs_dir_entry *)((char *)de + rec_len); + } + unlock_page(page); + nilfs_put_page(page); + } + BUG(); + return -EINVAL; + +got_it: + from = (char *)de - (char *)page_address(page); + to = from + rec_len; + err = nilfs_prepare_chunk(page, page->mapping, from, to); + if (err) + goto out_unlock; + if (de->inode) { + struct nilfs_dir_entry *de1; + + de1 = (struct nilfs_dir_entry *)((char *)de + name_len); + de1->rec_len = cpu_to_le16(rec_len - name_len); + de->rec_len = cpu_to_le16(name_len); + de = de1; + } + de->name_len = namelen; + memcpy(de->name, name, namelen); + de->inode = cpu_to_le64(inode->i_ino); + nilfs_set_de_type(de, inode); + err = nilfs_commit_chunk(page, page->mapping, from, to); + dir->i_mtime = dir->i_ctime = CURRENT_TIME; +/* NILFS_I(dir)->i_flags &= ~NILFS_BTREE_FL; */ + mark_inode_dirty(dir); + /* OFFSET_CACHE */ +out_put: + nilfs_put_page(page); +out: + return err; +out_unlock: + unlock_page(page); + goto out_put; +} + +/* + * nilfs_delete_entry deletes a directory entry by merging it with the + * previous entry. Page is up-to-date. Releases the page. + */ +int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = mapping->host; + char *kaddr = page_address(page); + unsigned from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1); + unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len); + struct nilfs_dir_entry *pde = NULL; + struct nilfs_dir_entry *de = (struct nilfs_dir_entry *)(kaddr + from); + int err; + + while ((char *)de < (char *)dir) { + if (de->rec_len == 0) { + nilfs_error(inode->i_sb, __func__, + "zero-length directory entry"); + err = -EIO; + goto out; + } + pde = de; + de = nilfs_next_entry(de); + } + if (pde) + from = (char *)pde - (char *)page_address(page); + lock_page(page); + err = nilfs_prepare_chunk(page, mapping, from, to); + BUG_ON(err); + if (pde) + pde->rec_len = cpu_to_le16(to - from); + dir->inode = 0; + err = nilfs_commit_chunk(page, mapping, from, to); + inode->i_ctime = inode->i_mtime = CURRENT_TIME; +/* NILFS_I(inode)->i_flags &= ~NILFS_BTREE_FL; */ + mark_inode_dirty(inode); +out: + nilfs_put_page(page); + return err; +} + +/* + * Set the first fragment of directory. + */ +int nilfs_make_empty(struct inode *inode, struct inode *parent) +{ + struct address_space *mapping = inode->i_mapping; + struct page *page = grab_cache_page(mapping, 0); + unsigned chunk_size = nilfs_chunk_size(inode); + struct nilfs_dir_entry *de; + int err; + void *kaddr; + + if (!page) + return -ENOMEM; + + err = nilfs_prepare_chunk(page, mapping, 0, chunk_size); + if (unlikely(err)) { + unlock_page(page); + goto fail; + } + kaddr = kmap_atomic(page, KM_USER0); + memset(kaddr, 0, chunk_size); + de = (struct nilfs_dir_entry *)kaddr; + de->name_len = 1; + de->rec_len = cpu_to_le16(NILFS_DIR_REC_LEN(1)); + memcpy(de->name, ".\0\0", 4); + de->inode = cpu_to_le64(inode->i_ino); + nilfs_set_de_type(de, inode); + + de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1)); + de->name_len = 2; + de->rec_len = cpu_to_le16(chunk_size - NILFS_DIR_REC_LEN(1)); + de->inode = cpu_to_le64(parent->i_ino); + memcpy(de->name, "..\0", 4); + nilfs_set_de_type(de, inode); + kunmap_atomic(kaddr, KM_USER0); + err = nilfs_commit_chunk(page, mapping, 0, chunk_size); +fail: + page_cache_release(page); + return err; +} + +/* + * routine to check that the specified directory is empty (for rmdir) + */ +int nilfs_empty_dir(struct inode *inode) +{ + struct page *page = NULL; + unsigned long i, npages = dir_pages(inode); + + for (i = 0; i < npages; i++) { + char *kaddr; + struct nilfs_dir_entry *de; + + page = nilfs_get_page(inode, i); + if (IS_ERR(page)) + continue; + + kaddr = page_address(page); + de = (struct nilfs_dir_entry *)kaddr; + kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1); + + while ((char *)de <= kaddr) { + if (de->rec_len == 0) { + nilfs_error(inode->i_sb, __func__, + "zero-length directory entry " + "(kaddr=%p, de=%p)\n", kaddr, de); + goto not_empty; + } + if (de->inode != 0) { + /* check for . and .. */ + if (de->name[0] != '.') + goto not_empty; + if (de->name_len > 2) + goto not_empty; + if (de->name_len < 2) { + if (de->inode != + cpu_to_le64(inode->i_ino)) + goto not_empty; + } else if (de->name[1] != '.') + goto not_empty; + } + de = nilfs_next_entry(de); + } + nilfs_put_page(page); + } + return 1; + +not_empty: + nilfs_put_page(page); + return 0; +} + +struct file_operations nilfs_dir_operations = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .readdir = nilfs_readdir, + .ioctl = nilfs_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = nilfs_compat_ioctl, +#endif /* CONFIG_COMPAT */ + .fsync = nilfs_sync_file, + +}; |