nilfs2: directory entry operations
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>
This commit is contained in:
Yoshiji Amagai
Linus Torvalds
parent
f183ff4f05
commit
2ba466d74e
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@ -0,0 +1,711 @@
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/*
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* dir.c - NILFS directory entry operations
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Modified for NILFS by Amagai Yoshiji <amagai@osrg.net>
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*/
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/*
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* linux/fs/ext2/dir.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/dir.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext2 directory handling functions
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*
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* Big-endian to little-endian byte-swapping/bitmaps by
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* David S. Miller (davem@caip.rutgers.edu), 1995
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*
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* All code that works with directory layout had been switched to pagecache
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* and moved here. AV
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*/
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#include <linux/pagemap.h>
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#include <linux/smp_lock.h>
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#include "nilfs.h"
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#include "page.h"
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/*
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* nilfs uses block-sized chunks. Arguably, sector-sized ones would be
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* more robust, but we have what we have
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*/
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static inline unsigned nilfs_chunk_size(struct inode *inode)
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{
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return inode->i_sb->s_blocksize;
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}
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static inline void nilfs_put_page(struct page *page)
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{
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kunmap(page);
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page_cache_release(page);
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}
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static inline unsigned long dir_pages(struct inode *inode)
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{
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return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
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}
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/*
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* Return the offset into page `page_nr' of the last valid
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* byte in that page, plus one.
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*/
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static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr)
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{
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unsigned last_byte = inode->i_size;
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last_byte -= page_nr << PAGE_CACHE_SHIFT;
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if (last_byte > PAGE_CACHE_SIZE)
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last_byte = PAGE_CACHE_SIZE;
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return last_byte;
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}
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static int nilfs_prepare_chunk_uninterruptible(struct page *page,
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struct address_space *mapping,
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unsigned from, unsigned to)
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{
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loff_t pos = page_offset(page) + from;
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return block_write_begin(NULL, mapping, pos, to - from,
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AOP_FLAG_UNINTERRUPTIBLE, &page,
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NULL, nilfs_get_block);
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}
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static int nilfs_prepare_chunk(struct page *page,
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struct address_space *mapping,
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unsigned from, unsigned to)
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{
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loff_t pos = page_offset(page) + from;
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return block_write_begin(NULL, mapping, pos, to - from, 0, &page,
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NULL, nilfs_get_block);
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}
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static int nilfs_commit_chunk(struct page *page,
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struct address_space *mapping,
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unsigned from, unsigned to)
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{
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struct inode *dir = mapping->host;
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struct nilfs_sb_info *sbi = NILFS_SB(dir->i_sb);
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loff_t pos = page_offset(page) + from;
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unsigned len = to - from;
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unsigned nr_dirty, copied;
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int err;
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nr_dirty = nilfs_page_count_clean_buffers(page, from, to);
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copied = block_write_end(NULL, mapping, pos, len, len, page, NULL);
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if (pos + copied > dir->i_size) {
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i_size_write(dir, pos + copied);
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mark_inode_dirty(dir);
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}
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if (IS_DIRSYNC(dir))
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nilfs_set_transaction_flag(NILFS_TI_SYNC);
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err = nilfs_set_file_dirty(sbi, dir, nr_dirty);
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unlock_page(page);
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return err;
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}
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static void nilfs_check_page(struct page *page)
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{
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struct inode *dir = page->mapping->host;
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struct super_block *sb = dir->i_sb;
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unsigned chunk_size = nilfs_chunk_size(dir);
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char *kaddr = page_address(page);
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unsigned offs, rec_len;
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unsigned limit = PAGE_CACHE_SIZE;
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struct nilfs_dir_entry *p;
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char *error;
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if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
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limit = dir->i_size & ~PAGE_CACHE_MASK;
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if (limit & (chunk_size - 1))
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goto Ebadsize;
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if (!limit)
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goto out;
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}
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for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) {
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p = (struct nilfs_dir_entry *)(kaddr + offs);
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rec_len = le16_to_cpu(p->rec_len);
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if (rec_len < NILFS_DIR_REC_LEN(1))
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goto Eshort;
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if (rec_len & 3)
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goto Ealign;
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if (rec_len < NILFS_DIR_REC_LEN(p->name_len))
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goto Enamelen;
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if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
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goto Espan;
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}
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if (offs != limit)
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goto Eend;
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out:
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SetPageChecked(page);
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return;
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/* Too bad, we had an error */
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Ebadsize:
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nilfs_error(sb, "nilfs_check_page",
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"size of directory #%lu is not a multiple of chunk size",
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dir->i_ino
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);
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goto fail;
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Eshort:
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error = "rec_len is smaller than minimal";
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goto bad_entry;
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Ealign:
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error = "unaligned directory entry";
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goto bad_entry;
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Enamelen:
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error = "rec_len is too small for name_len";
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goto bad_entry;
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Espan:
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error = "directory entry across blocks";
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bad_entry:
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nilfs_error(sb, "nilfs_check_page", "bad entry in directory #%lu: %s - "
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"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
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dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
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(unsigned long) le64_to_cpu(p->inode),
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rec_len, p->name_len);
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goto fail;
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Eend:
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p = (struct nilfs_dir_entry *)(kaddr + offs);
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nilfs_error(sb, "nilfs_check_page",
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"entry in directory #%lu spans the page boundary"
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"offset=%lu, inode=%lu",
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dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
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(unsigned long) le64_to_cpu(p->inode));
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fail:
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SetPageChecked(page);
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SetPageError(page);
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}
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static struct page *nilfs_get_page(struct inode *dir, unsigned long n)
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{
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struct address_space *mapping = dir->i_mapping;
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struct page *page = read_cache_page(mapping, n,
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(filler_t *)mapping->a_ops->readpage, NULL);
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if (!IS_ERR(page)) {
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wait_on_page_locked(page);
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kmap(page);
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if (!PageUptodate(page))
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goto fail;
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if (!PageChecked(page))
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nilfs_check_page(page);
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if (PageError(page))
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goto fail;
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}
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return page;
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fail:
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nilfs_put_page(page);
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return ERR_PTR(-EIO);
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}
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/*
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* NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure.
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*
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* len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller.
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*/
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static int
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nilfs_match(int len, const char * const name, struct nilfs_dir_entry *de)
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{
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if (len != de->name_len)
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return 0;
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if (!de->inode)
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return 0;
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return !memcmp(name, de->name, len);
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}
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/*
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* p is at least 6 bytes before the end of page
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*/
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static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p)
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{
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return (struct nilfs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
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}
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static unsigned char
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nilfs_filetype_table[NILFS_FT_MAX] = {
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[NILFS_FT_UNKNOWN] = DT_UNKNOWN,
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[NILFS_FT_REG_FILE] = DT_REG,
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[NILFS_FT_DIR] = DT_DIR,
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[NILFS_FT_CHRDEV] = DT_CHR,
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[NILFS_FT_BLKDEV] = DT_BLK,
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[NILFS_FT_FIFO] = DT_FIFO,
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[NILFS_FT_SOCK] = DT_SOCK,
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[NILFS_FT_SYMLINK] = DT_LNK,
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};
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#define S_SHIFT 12
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static unsigned char
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nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
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[S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
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[S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
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[S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
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[S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV,
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[S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO,
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[S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK,
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[S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK,
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};
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static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode)
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{
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mode_t mode = inode->i_mode;
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de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
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}
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static int nilfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
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{
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loff_t pos = filp->f_pos;
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struct inode *inode = filp->f_dentry->d_inode;
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struct super_block *sb = inode->i_sb;
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unsigned int offset = pos & ~PAGE_CACHE_MASK;
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unsigned long n = pos >> PAGE_CACHE_SHIFT;
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unsigned long npages = dir_pages(inode);
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/* unsigned chunk_mask = ~(nilfs_chunk_size(inode)-1); */
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unsigned char *types = NULL;
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int ret;
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if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
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goto success;
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types = nilfs_filetype_table;
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for ( ; n < npages; n++, offset = 0) {
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char *kaddr, *limit;
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struct nilfs_dir_entry *de;
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struct page *page = nilfs_get_page(inode, n);
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if (IS_ERR(page)) {
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nilfs_error(sb, __func__, "bad page in #%lu",
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inode->i_ino);
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filp->f_pos += PAGE_CACHE_SIZE - offset;
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ret = -EIO;
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goto done;
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}
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kaddr = page_address(page);
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de = (struct nilfs_dir_entry *)(kaddr + offset);
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limit = kaddr + nilfs_last_byte(inode, n) -
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NILFS_DIR_REC_LEN(1);
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for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) {
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if (de->rec_len == 0) {
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nilfs_error(sb, __func__,
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"zero-length directory entry");
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ret = -EIO;
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nilfs_put_page(page);
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goto done;
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}
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if (de->inode) {
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int over;
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unsigned char d_type = DT_UNKNOWN;
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if (types && de->file_type < NILFS_FT_MAX)
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d_type = types[de->file_type];
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offset = (char *)de - kaddr;
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over = filldir(dirent, de->name, de->name_len,
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(n<<PAGE_CACHE_SHIFT) | offset,
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le64_to_cpu(de->inode), d_type);
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if (over) {
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nilfs_put_page(page);
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goto success;
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}
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}
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filp->f_pos += le16_to_cpu(de->rec_len);
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}
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nilfs_put_page(page);
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}
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success:
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ret = 0;
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done:
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return ret;
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}
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/*
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* nilfs_find_entry()
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*
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* finds an entry in the specified directory with the wanted name. It
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* returns the page in which the entry was found, and the entry itself
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* (as a parameter - res_dir). Page is returned mapped and unlocked.
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* Entry is guaranteed to be valid.
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*/
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struct nilfs_dir_entry *
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nilfs_find_entry(struct inode *dir, struct dentry *dentry,
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struct page **res_page)
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{
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const char *name = dentry->d_name.name;
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int namelen = dentry->d_name.len;
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unsigned reclen = NILFS_DIR_REC_LEN(namelen);
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unsigned long start, n;
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unsigned long npages = dir_pages(dir);
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struct page *page = NULL;
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struct nilfs_inode_info *ei = NILFS_I(dir);
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struct nilfs_dir_entry *de;
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if (npages == 0)
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goto out;
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/* OFFSET_CACHE */
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*res_page = NULL;
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start = ei->i_dir_start_lookup;
|
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if (start >= npages)
|
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start = 0;
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n = start;
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do {
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char *kaddr;
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page = nilfs_get_page(dir, n);
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if (!IS_ERR(page)) {
|
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kaddr = page_address(page);
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de = (struct nilfs_dir_entry *)kaddr;
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kaddr += nilfs_last_byte(dir, n) - reclen;
|
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while ((char *) de <= kaddr) {
|
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if (de->rec_len == 0) {
|
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nilfs_error(dir->i_sb, __func__,
|
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"zero-length directory entry");
|
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nilfs_put_page(page);
|
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goto out;
|
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}
|
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if (nilfs_match(namelen, name, de))
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goto found;
|
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de = nilfs_next_entry(de);
|
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}
|
||||
nilfs_put_page(page);
|
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}
|
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if (++n >= npages)
|
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n = 0;
|
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/* next page is past the blocks we've got */
|
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if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
|
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nilfs_error(dir->i_sb, __func__,
|
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"dir %lu size %lld exceeds block cout %llu",
|
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dir->i_ino, dir->i_size,
|
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(unsigned long long)dir->i_blocks);
|
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goto out;
|
||||
}
|
||||
} while (n != start);
|
||||
out:
|
||||
return NULL;
|
||||
|
||||
found:
|
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*res_page = page;
|
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ei->i_dir_start_lookup = n;
|
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return de;
|
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}
|
||||
|
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struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p)
|
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{
|
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struct page *page = nilfs_get_page(dir, 0);
|
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struct nilfs_dir_entry *de = NULL;
|
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|
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if (!IS_ERR(page)) {
|
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de = nilfs_next_entry(
|
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(struct nilfs_dir_entry *)page_address(page));
|
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*p = page;
|
||||
}
|
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return de;
|
||||
}
|
||||
|
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ino_t nilfs_inode_by_name(struct inode *dir, struct dentry *dentry)
|
||||
{
|
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ino_t res = 0;
|
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struct nilfs_dir_entry *de;
|
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struct page *page;
|
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|
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de = nilfs_find_entry(dir, dentry, &page);
|
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if (de) {
|
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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,
|
||||
|
||||
};
|
||||
Loading…
Reference in New Issue