Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / ext2 / dir.c
diff --git a/kernel/fs/ext2/dir.c b/kernel/fs/ext2/dir.c
new file mode 100644 (file)
index 0000000..796b491
--- /dev/null
@@ -0,0 +1,730 @@
+/*
+ *  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 "ext2.h"
+#include <linux/buffer_head.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+
+typedef struct ext2_dir_entry_2 ext2_dirent;
+
+/*
+ * Tests against MAX_REC_LEN etc were put in place for 64k block
+ * sizes; if that is not possible on this arch, we can skip
+ * those tests and speed things up.
+ */
+static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
+{
+       unsigned len = le16_to_cpu(dlen);
+
+#if (PAGE_CACHE_SIZE >= 65536)
+       if (len == EXT2_MAX_REC_LEN)
+               return 1 << 16;
+#endif
+       return len;
+}
+
+static inline __le16 ext2_rec_len_to_disk(unsigned len)
+{
+#if (PAGE_CACHE_SIZE >= 65536)
+       if (len == (1 << 16))
+               return cpu_to_le16(EXT2_MAX_REC_LEN);
+       else
+               BUG_ON(len > (1 << 16));
+#endif
+       return cpu_to_le16(len);
+}
+
+/*
+ * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
+ * more robust, but we have what we have
+ */
+static inline unsigned ext2_chunk_size(struct inode *inode)
+{
+       return inode->i_sb->s_blocksize;
+}
+
+static inline void ext2_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
+ext2_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 ext2_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);
+               if (!err)
+                       err = sync_inode_metadata(dir, 1);
+       } else {
+               unlock_page(page);
+       }
+
+       return err;
+}
+
+static void ext2_check_page(struct page *page, int quiet)
+{
+       struct inode *dir = page->mapping->host;
+       struct super_block *sb = dir->i_sb;
+       unsigned chunk_size = ext2_chunk_size(dir);
+       char *kaddr = page_address(page);
+       u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
+       unsigned offs, rec_len;
+       unsigned limit = PAGE_CACHE_SIZE;
+       ext2_dirent *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 - EXT2_DIR_REC_LEN(1); offs += rec_len) {
+               p = (ext2_dirent *)(kaddr + offs);
+               rec_len = ext2_rec_len_from_disk(p->rec_len);
+
+               if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
+                       goto Eshort;
+               if (unlikely(rec_len & 3))
+                       goto Ealign;
+               if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
+                       goto Enamelen;
+               if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
+                       goto Espan;
+               if (unlikely(le32_to_cpu(p->inode) > max_inumber))
+                       goto Einumber;
+       }
+       if (offs != limit)
+               goto Eend;
+out:
+       SetPageChecked(page);
+       return;
+
+       /* Too bad, we had an error */
+
+Ebadsize:
+       if (!quiet)
+               ext2_error(sb, __func__,
+                       "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:
+       if (!quiet)
+               ext2_error(sb, __func__, "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) le32_to_cpu(p->inode),
+                       rec_len, p->name_len);
+       goto fail;
+Eend:
+       if (!quiet) {
+               p = (ext2_dirent *)(kaddr + offs);
+               ext2_error(sb, "ext2_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) le32_to_cpu(p->inode));
+       }
+fail:
+       SetPageChecked(page);
+       SetPageError(page);
+}
+
+static struct page * ext2_get_page(struct inode *dir, unsigned long n,
+                                  int quiet)
+{
+       struct address_space *mapping = dir->i_mapping;
+       struct page *page = read_mapping_page(mapping, n, NULL);
+       if (!IS_ERR(page)) {
+               kmap(page);
+               if (!PageChecked(page))
+                       ext2_check_page(page, quiet);
+               if (PageError(page))
+                       goto fail;
+       }
+       return page;
+
+fail:
+       ext2_put_page(page);
+       return ERR_PTR(-EIO);
+}
+
+/*
+ * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
+ *
+ * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
+ */
+static inline int ext2_match (int len, const char * const name,
+                                       struct ext2_dir_entry_2 * 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 inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
+{
+       return (ext2_dirent *)((char *)p +
+                       ext2_rec_len_from_disk(p->rec_len));
+}
+
+static inline unsigned 
+ext2_validate_entry(char *base, unsigned offset, unsigned mask)
+{
+       ext2_dirent *de = (ext2_dirent*)(base + offset);
+       ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
+       while ((char*)p < (char*)de) {
+               if (p->rec_len == 0)
+                       break;
+               p = ext2_next_entry(p);
+       }
+       return (char *)p - base;
+}
+
+static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
+       [EXT2_FT_UNKNOWN]       = DT_UNKNOWN,
+       [EXT2_FT_REG_FILE]      = DT_REG,
+       [EXT2_FT_DIR]           = DT_DIR,
+       [EXT2_FT_CHRDEV]        = DT_CHR,
+       [EXT2_FT_BLKDEV]        = DT_BLK,
+       [EXT2_FT_FIFO]          = DT_FIFO,
+       [EXT2_FT_SOCK]          = DT_SOCK,
+       [EXT2_FT_SYMLINK]       = DT_LNK,
+};
+
+#define S_SHIFT 12
+static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
+       [S_IFREG >> S_SHIFT]    = EXT2_FT_REG_FILE,
+       [S_IFDIR >> S_SHIFT]    = EXT2_FT_DIR,
+       [S_IFCHR >> S_SHIFT]    = EXT2_FT_CHRDEV,
+       [S_IFBLK >> S_SHIFT]    = EXT2_FT_BLKDEV,
+       [S_IFIFO >> S_SHIFT]    = EXT2_FT_FIFO,
+       [S_IFSOCK >> S_SHIFT]   = EXT2_FT_SOCK,
+       [S_IFLNK >> S_SHIFT]    = EXT2_FT_SYMLINK,
+};
+
+static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
+{
+       umode_t mode = inode->i_mode;
+       if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
+               de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
+       else
+               de->file_type = 0;
+}
+
+static int
+ext2_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_CACHE_MASK;
+       unsigned long n = pos >> PAGE_CACHE_SHIFT;
+       unsigned long npages = dir_pages(inode);
+       unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
+       unsigned char *types = NULL;
+       int need_revalidate = file->f_version != inode->i_version;
+
+       if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
+               return 0;
+
+       if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
+               types = ext2_filetype_table;
+
+       for ( ; n < npages; n++, offset = 0) {
+               char *kaddr, *limit;
+               ext2_dirent *de;
+               struct page *page = ext2_get_page(inode, n, 0);
+
+               if (IS_ERR(page)) {
+                       ext2_error(sb, __func__,
+                                  "bad page in #%lu",
+                                  inode->i_ino);
+                       ctx->pos += PAGE_CACHE_SIZE - offset;
+                       return PTR_ERR(page);
+               }
+               kaddr = page_address(page);
+               if (unlikely(need_revalidate)) {
+                       if (offset) {
+                               offset = ext2_validate_entry(kaddr, offset, chunk_mask);
+                               ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset;
+                       }
+                       file->f_version = inode->i_version;
+                       need_revalidate = 0;
+               }
+               de = (ext2_dirent *)(kaddr+offset);
+               limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
+               for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
+                       if (de->rec_len == 0) {
+                               ext2_error(sb, __func__,
+                                       "zero-length directory entry");
+                               ext2_put_page(page);
+                               return -EIO;
+                       }
+                       if (de->inode) {
+                               unsigned char d_type = DT_UNKNOWN;
+
+                               if (types && de->file_type < EXT2_FT_MAX)
+                                       d_type = types[de->file_type];
+
+                               if (!dir_emit(ctx, de->name, de->name_len,
+                                               le32_to_cpu(de->inode),
+                                               d_type)) {
+                                       ext2_put_page(page);
+                                       return 0;
+                               }
+                       }
+                       ctx->pos += ext2_rec_len_from_disk(de->rec_len);
+               }
+               ext2_put_page(page);
+       }
+       return 0;
+}
+
+/*
+ *     ext2_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the page in which the entry was found (as a parameter - res_page),
+ * and the entry itself. Page is returned mapped and unlocked.
+ * Entry is guaranteed to be valid.
+ */
+struct ext2_dir_entry_2 *ext2_find_entry (struct inode * dir,
+                       struct qstr *child, struct page ** res_page)
+{
+       const char *name = child->name;
+       int namelen = child->len;
+       unsigned reclen = EXT2_DIR_REC_LEN(namelen);
+       unsigned long start, n;
+       unsigned long npages = dir_pages(dir);
+       struct page *page = NULL;
+       struct ext2_inode_info *ei = EXT2_I(dir);
+       ext2_dirent * de;
+       int dir_has_error = 0;
+
+       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 = ext2_get_page(dir, n, dir_has_error);
+               if (!IS_ERR(page)) {
+                       kaddr = page_address(page);
+                       de = (ext2_dirent *) kaddr;
+                       kaddr += ext2_last_byte(dir, n) - reclen;
+                       while ((char *) de <= kaddr) {
+                               if (de->rec_len == 0) {
+                                       ext2_error(dir->i_sb, __func__,
+                                               "zero-length directory entry");
+                                       ext2_put_page(page);
+                                       goto out;
+                               }
+                               if (ext2_match (namelen, name, de))
+                                       goto found;
+                               de = ext2_next_entry(de);
+                       }
+                       ext2_put_page(page);
+               } else
+                       dir_has_error = 1;
+
+               if (++n >= npages)
+                       n = 0;
+               /* next page is past the blocks we've got */
+               if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
+                       ext2_error(dir->i_sb, __func__,
+                               "dir %lu size %lld exceeds block count %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 ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
+{
+       struct page *page = ext2_get_page(dir, 0, 0);
+       ext2_dirent *de = NULL;
+
+       if (!IS_ERR(page)) {
+               de = ext2_next_entry((ext2_dirent *) page_address(page));
+               *p = page;
+       }
+       return de;
+}
+
+ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
+{
+       ino_t res = 0;
+       struct ext2_dir_entry_2 *de;
+       struct page *page;
+       
+       de = ext2_find_entry (dir, child, &page);
+       if (de) {
+               res = le32_to_cpu(de->inode);
+               ext2_put_page(page);
+       }
+       return res;
+}
+
+static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
+{
+       return __block_write_begin(page, pos, len, ext2_get_block);
+}
+
+/* Releases the page */
+void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
+                  struct page *page, struct inode *inode, int update_times)
+{
+       loff_t pos = page_offset(page) +
+                       (char *) de - (char *) page_address(page);
+       unsigned len = ext2_rec_len_from_disk(de->rec_len);
+       int err;
+
+       lock_page(page);
+       err = ext2_prepare_chunk(page, pos, len);
+       BUG_ON(err);
+       de->inode = cpu_to_le32(inode->i_ino);
+       ext2_set_de_type(de, inode);
+       err = ext2_commit_chunk(page, pos, len);
+       ext2_put_page(page);
+       if (update_times)
+               dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+       EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
+       mark_inode_dirty(dir);
+}
+
+/*
+ *     Parent is locked.
+ */
+int ext2_add_link (struct dentry *dentry, struct inode *inode)
+{
+       struct inode *dir = d_inode(dentry->d_parent);
+       const char *name = dentry->d_name.name;
+       int namelen = dentry->d_name.len;
+       unsigned chunk_size = ext2_chunk_size(dir);
+       unsigned reclen = EXT2_DIR_REC_LEN(namelen);
+       unsigned short rec_len, name_len;
+       struct page *page = NULL;
+       ext2_dirent * de;
+       unsigned long npages = dir_pages(dir);
+       unsigned long n;
+       char *kaddr;
+       loff_t pos;
+       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 = ext2_get_page(dir, n, 0);
+               err = PTR_ERR(page);
+               if (IS_ERR(page))
+                       goto out;
+               lock_page(page);
+               kaddr = page_address(page);
+               dir_end = kaddr + ext2_last_byte(dir, n);
+               de = (ext2_dirent *)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 = ext2_rec_len_to_disk(chunk_size);
+                               de->inode = 0;
+                               goto got_it;
+                       }
+                       if (de->rec_len == 0) {
+                               ext2_error(dir->i_sb, __func__,
+                                       "zero-length directory entry");
+                               err = -EIO;
+                               goto out_unlock;
+                       }
+                       err = -EEXIST;
+                       if (ext2_match (namelen, name, de))
+                               goto out_unlock;
+                       name_len = EXT2_DIR_REC_LEN(de->name_len);
+                       rec_len = ext2_rec_len_from_disk(de->rec_len);
+                       if (!de->inode && rec_len >= reclen)
+                               goto got_it;
+                       if (rec_len >= name_len + reclen)
+                               goto got_it;
+                       de = (ext2_dirent *) ((char *) de + rec_len);
+               }
+               unlock_page(page);
+               ext2_put_page(page);
+       }
+       BUG();
+       return -EINVAL;
+
+got_it:
+       pos = page_offset(page) +
+               (char*)de - (char*)page_address(page);
+       err = ext2_prepare_chunk(page, pos, rec_len);
+       if (err)
+               goto out_unlock;
+       if (de->inode) {
+               ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
+               de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
+               de->rec_len = ext2_rec_len_to_disk(name_len);
+               de = de1;
+       }
+       de->name_len = namelen;
+       memcpy(de->name, name, namelen);
+       de->inode = cpu_to_le32(inode->i_ino);
+       ext2_set_de_type (de, inode);
+       err = ext2_commit_chunk(page, pos, rec_len);
+       dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+       EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
+       mark_inode_dirty(dir);
+       /* OFFSET_CACHE */
+out_put:
+       ext2_put_page(page);
+out:
+       return err;
+out_unlock:
+       unlock_page(page);
+       goto out_put;
+}
+
+/*
+ * ext2_delete_entry deletes a directory entry by merging it with the
+ * previous entry. Page is up-to-date. Releases the page.
+ */
+int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
+{
+       struct inode *inode = page->mapping->host;
+       char *kaddr = page_address(page);
+       unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
+       unsigned to = ((char *)dir - kaddr) +
+                               ext2_rec_len_from_disk(dir->rec_len);
+       loff_t pos;
+       ext2_dirent * pde = NULL;
+       ext2_dirent * de = (ext2_dirent *) (kaddr + from);
+       int err;
+
+       while ((char*)de < (char*)dir) {
+               if (de->rec_len == 0) {
+                       ext2_error(inode->i_sb, __func__,
+                               "zero-length directory entry");
+                       err = -EIO;
+                       goto out;
+               }
+               pde = de;
+               de = ext2_next_entry(de);
+       }
+       if (pde)
+               from = (char*)pde - (char*)page_address(page);
+       pos = page_offset(page) + from;
+       lock_page(page);
+       err = ext2_prepare_chunk(page, pos, to - from);
+       BUG_ON(err);
+       if (pde)
+               pde->rec_len = ext2_rec_len_to_disk(to - from);
+       dir->inode = 0;
+       err = ext2_commit_chunk(page, pos, to - from);
+       inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+       EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
+       mark_inode_dirty(inode);
+out:
+       ext2_put_page(page);
+       return err;
+}
+
+/*
+ * Set the first fragment of directory.
+ */
+int ext2_make_empty(struct inode *inode, struct inode *parent)
+{
+       struct page *page = grab_cache_page(inode->i_mapping, 0);
+       unsigned chunk_size = ext2_chunk_size(inode);
+       struct ext2_dir_entry_2 * de;
+       int err;
+       void *kaddr;
+
+       if (!page)
+               return -ENOMEM;
+
+       err = ext2_prepare_chunk(page, 0, chunk_size);
+       if (err) {
+               unlock_page(page);
+               goto fail;
+       }
+       kaddr = kmap_atomic(page);
+       memset(kaddr, 0, chunk_size);
+       de = (struct ext2_dir_entry_2 *)kaddr;
+       de->name_len = 1;
+       de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
+       memcpy (de->name, ".\0\0", 4);
+       de->inode = cpu_to_le32(inode->i_ino);
+       ext2_set_de_type (de, inode);
+
+       de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
+       de->name_len = 2;
+       de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
+       de->inode = cpu_to_le32(parent->i_ino);
+       memcpy (de->name, "..\0", 4);
+       ext2_set_de_type (de, inode);
+       kunmap_atomic(kaddr);
+       err = ext2_commit_chunk(page, 0, chunk_size);
+fail:
+       page_cache_release(page);
+       return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+int ext2_empty_dir (struct inode * inode)
+{
+       struct page *page = NULL;
+       unsigned long i, npages = dir_pages(inode);
+       int dir_has_error = 0;
+
+       for (i = 0; i < npages; i++) {
+               char *kaddr;
+               ext2_dirent * de;
+               page = ext2_get_page(inode, i, dir_has_error);
+
+               if (IS_ERR(page)) {
+                       dir_has_error = 1;
+                       continue;
+               }
+
+               kaddr = page_address(page);
+               de = (ext2_dirent *)kaddr;
+               kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
+
+               while ((char *)de <= kaddr) {
+                       if (de->rec_len == 0) {
+                               ext2_error(inode->i_sb, __func__,
+                                       "zero-length directory entry");
+                               printk("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_le32(inode->i_ino))
+                                               goto not_empty;
+                               } else if (de->name[1] != '.')
+                                       goto not_empty;
+                       }
+                       de = ext2_next_entry(de);
+               }
+               ext2_put_page(page);
+       }
+       return 1;
+
+not_empty:
+       ext2_put_page(page);
+       return 0;
+}
+
+const struct file_operations ext2_dir_operations = {
+       .llseek         = generic_file_llseek,
+       .read           = generic_read_dir,
+       .iterate        = ext2_readdir,
+       .unlocked_ioctl = ext2_ioctl,
+#ifdef CONFIG_COMPAT
+       .compat_ioctl   = ext2_compat_ioctl,
+#endif
+       .fsync          = ext2_fsync,
+};