]> pilppa.com Git - linux-2.6-omap-h63xx.git/commitdiff
nilfs2: directory entry operations
authorYoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Tue, 7 Apr 2009 02:01:34 +0000 (19:01 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 7 Apr 2009 15:31:15 +0000 (08:31 -0700)
This adds directory handling functions, most of which comes from the ext2
file system.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Yoshiji Amagai <amagai.yoshiji@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/nilfs2/dir.c [new file with mode: 0644]

diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
new file mode 100644 (file)
index 0000000..1b7e6dd
--- /dev/null
@@ -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,
+
+};