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![Deepa Dinamani](/assets/img/avatar_default.png)
CURRENT_TIME macro is not appropriate for filesystems as it doesn't use the right granularity for filesystem timestamps. Use current_time() instead. CURRENT_TIME is also not y2038 safe. This is also in preparation for the patch that transitions vfs timestamps to use 64 bit time and hence make them y2038 safe. As part of the effort current_time() will be extended to do range checks. Hence, it is necessary for all file system timestamps to use current_time(). Also, current_time() will be transitioned along with vfs to be y2038 safe. Note that whenever a single call to current_time() is used to change timestamps in different inodes, it is because they share the same time granularity. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Felipe Balbi <balbi@kernel.org> Acked-by: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Acked-by: David Sterba <dsterba@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
688 lines
17 KiB
C
688 lines
17 KiB
C
/*
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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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* Modified for NILFS by Amagai Yoshiji.
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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 "nilfs.h"
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#include "page.h"
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static inline unsigned int nilfs_rec_len_from_disk(__le16 dlen)
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{
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unsigned int len = le16_to_cpu(dlen);
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#if (PAGE_SIZE >= 65536)
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if (len == NILFS_MAX_REC_LEN)
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return 1 << 16;
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#endif
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return len;
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}
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static inline __le16 nilfs_rec_len_to_disk(unsigned int len)
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{
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#if (PAGE_SIZE >= 65536)
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if (len == (1 << 16))
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return cpu_to_le16(NILFS_MAX_REC_LEN);
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BUG_ON(len > (1 << 16));
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#endif
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return cpu_to_le16(len);
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}
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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 int 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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put_page(page);
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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 int nilfs_last_byte(struct inode *inode, unsigned long page_nr)
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{
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unsigned int last_byte = inode->i_size;
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last_byte -= page_nr << PAGE_SHIFT;
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if (last_byte > PAGE_SIZE)
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last_byte = PAGE_SIZE;
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return last_byte;
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}
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static int nilfs_prepare_chunk(struct page *page, unsigned int from,
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unsigned int to)
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{
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loff_t pos = page_offset(page) + from;
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return __block_write_begin(page, pos, to - from, nilfs_get_block);
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}
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static void nilfs_commit_chunk(struct page *page,
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struct address_space *mapping,
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unsigned int from, unsigned int to)
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{
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struct inode *dir = mapping->host;
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loff_t pos = page_offset(page) + from;
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unsigned int len = to - from;
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unsigned int 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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if (IS_DIRSYNC(dir))
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nilfs_set_transaction_flag(NILFS_TI_SYNC);
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err = nilfs_set_file_dirty(dir, nr_dirty);
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WARN_ON(err); /* do not happen */
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unlock_page(page);
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}
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static bool 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 int chunk_size = nilfs_chunk_size(dir);
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char *kaddr = page_address(page);
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unsigned int offs, rec_len;
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unsigned int limit = PAGE_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_SHIFT) == page->index) {
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limit = dir->i_size & ~PAGE_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 = nilfs_rec_len_from_disk(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 true;
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/* Too bad, we had an error */
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Ebadsize:
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nilfs_error(sb,
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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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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,
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"bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
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dir->i_ino, error, (page->index << PAGE_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,
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"entry in directory #%lu spans the page boundary offset=%lu, inode=%lu",
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dir->i_ino, (page->index << PAGE_SHIFT) + offs,
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(unsigned long)le64_to_cpu(p->inode));
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fail:
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SetPageError(page);
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return false;
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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_mapping_page(mapping, n, NULL);
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if (!IS_ERR(page)) {
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kmap(page);
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if (unlikely(!PageChecked(page))) {
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if (PageError(page) || !nilfs_check_page(page))
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goto fail;
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}
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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 unsigned char *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 +
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nilfs_rec_len_from_disk(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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umode_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 *file, struct dir_context *ctx)
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{
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loff_t pos = ctx->pos;
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struct inode *inode = file_inode(file);
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struct super_block *sb = inode->i_sb;
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unsigned int offset = pos & ~PAGE_MASK;
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unsigned long n = pos >> PAGE_SHIFT;
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unsigned long npages = dir_pages(inode);
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if (pos > inode->i_size - NILFS_DIR_REC_LEN(1))
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return 0;
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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, "bad page in #%lu", inode->i_ino);
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ctx->pos += PAGE_SIZE - offset;
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return -EIO;
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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, "zero-length directory entry");
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nilfs_put_page(page);
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return -EIO;
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}
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if (de->inode) {
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unsigned char t;
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if (de->file_type < NILFS_FT_MAX)
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t = nilfs_filetype_table[de->file_type];
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else
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t = DT_UNKNOWN;
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if (!dir_emit(ctx, de->name, de->name_len,
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le64_to_cpu(de->inode), t)) {
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nilfs_put_page(page);
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return 0;
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}
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}
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ctx->pos += nilfs_rec_len_from_disk(de->rec_len);
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}
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nilfs_put_page(page);
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}
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return 0;
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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, const struct qstr *qstr,
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struct page **res_page)
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{
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const unsigned char *name = qstr->name;
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int namelen = qstr->len;
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unsigned int 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,
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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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}
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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_SHIFT - 9)))) {
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nilfs_error(dir->i_sb,
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"dir %lu size %lld exceeds block count %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;
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}
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} while (n != start);
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out:
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return NULL;
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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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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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}
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return de;
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}
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ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
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{
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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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de = nilfs_find_entry(dir, qstr, &page);
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if (de) {
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res = le64_to_cpu(de->inode);
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kunmap(page);
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put_page(page);
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}
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return res;
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}
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/* Releases the page */
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void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de,
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struct page *page, struct inode *inode)
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{
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unsigned int from = (char *)de - (char *)page_address(page);
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unsigned int to = from + nilfs_rec_len_from_disk(de->rec_len);
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struct address_space *mapping = page->mapping;
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int err;
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lock_page(page);
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err = nilfs_prepare_chunk(page, from, to);
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BUG_ON(err);
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de->inode = cpu_to_le64(inode->i_ino);
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nilfs_set_de_type(de, inode);
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nilfs_commit_chunk(page, mapping, from, to);
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nilfs_put_page(page);
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dir->i_mtime = dir->i_ctime = current_time(dir);
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}
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/*
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* Parent is locked.
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*/
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int nilfs_add_link(struct dentry *dentry, struct inode *inode)
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{
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struct inode *dir = d_inode(dentry->d_parent);
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const unsigned char *name = dentry->d_name.name;
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int namelen = dentry->d_name.len;
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unsigned int chunk_size = nilfs_chunk_size(dir);
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unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
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unsigned short rec_len, name_len;
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struct page *page = NULL;
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struct nilfs_dir_entry *de;
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unsigned long npages = dir_pages(dir);
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unsigned long n;
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char *kaddr;
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unsigned int from, to;
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int err;
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/*
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* We take care of directory expansion in the same loop.
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* This code plays outside i_size, so it locks the page
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* to protect that region.
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*/
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for (n = 0; n <= npages; n++) {
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char *dir_end;
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page = nilfs_get_page(dir, n);
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err = PTR_ERR(page);
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if (IS_ERR(page))
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goto out;
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lock_page(page);
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kaddr = page_address(page);
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dir_end = kaddr + nilfs_last_byte(dir, n);
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de = (struct nilfs_dir_entry *)kaddr;
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kaddr += PAGE_SIZE - reclen;
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while ((char *)de <= kaddr) {
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if ((char *)de == dir_end) {
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/* We hit i_size */
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name_len = 0;
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rec_len = chunk_size;
|
|
de->rec_len = nilfs_rec_len_to_disk(chunk_size);
|
|
de->inode = 0;
|
|
goto got_it;
|
|
}
|
|
if (de->rec_len == 0) {
|
|
nilfs_error(dir->i_sb,
|
|
"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 = nilfs_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 = (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, 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 = nilfs_rec_len_to_disk(rec_len - name_len);
|
|
de->rec_len = nilfs_rec_len_to_disk(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);
|
|
nilfs_commit_chunk(page, page->mapping, from, to);
|
|
dir->i_mtime = dir->i_ctime = current_time(dir);
|
|
nilfs_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 int from, to;
|
|
struct nilfs_dir_entry *de, *pde = NULL;
|
|
int err;
|
|
|
|
from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1);
|
|
to = ((char *)dir - kaddr) + nilfs_rec_len_from_disk(dir->rec_len);
|
|
de = (struct nilfs_dir_entry *)(kaddr + from);
|
|
|
|
while ((char *)de < (char *)dir) {
|
|
if (de->rec_len == 0) {
|
|
nilfs_error(inode->i_sb,
|
|
"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, from, to);
|
|
BUG_ON(err);
|
|
if (pde)
|
|
pde->rec_len = nilfs_rec_len_to_disk(to - from);
|
|
dir->inode = 0;
|
|
nilfs_commit_chunk(page, mapping, from, to);
|
|
inode->i_ctime = inode->i_mtime = current_time(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 int chunk_size = nilfs_chunk_size(inode);
|
|
struct nilfs_dir_entry *de;
|
|
int err;
|
|
void *kaddr;
|
|
|
|
if (!page)
|
|
return -ENOMEM;
|
|
|
|
err = nilfs_prepare_chunk(page, 0, chunk_size);
|
|
if (unlikely(err)) {
|
|
unlock_page(page);
|
|
goto fail;
|
|
}
|
|
kaddr = kmap_atomic(page);
|
|
memset(kaddr, 0, chunk_size);
|
|
de = (struct nilfs_dir_entry *)kaddr;
|
|
de->name_len = 1;
|
|
de->rec_len = nilfs_rec_len_to_disk(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 = nilfs_rec_len_to_disk(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);
|
|
nilfs_commit_chunk(page, mapping, 0, chunk_size);
|
|
fail:
|
|
put_page(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,
|
|
"zero-length directory entry (kaddr=%p, de=%p)",
|
|
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;
|
|
}
|
|
|
|
const struct file_operations nilfs_dir_operations = {
|
|
.llseek = generic_file_llseek,
|
|
.read = generic_read_dir,
|
|
.iterate_shared = nilfs_readdir,
|
|
.unlocked_ioctl = nilfs_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = nilfs_compat_ioctl,
|
|
#endif /* CONFIG_COMPAT */
|
|
.fsync = nilfs_sync_file,
|
|
|
|
};
|