forked from Minki/linux
496ad9aa8e
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
667 lines
16 KiB
C
667 lines
16 KiB
C
/*
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* linux/fs/ufs/ufs_dir.c
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*
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* Copyright (C) 1996
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* Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
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* Laboratory for Computer Science Research Computing Facility
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* Rutgers, The State University of New Jersey
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*
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* swab support by Francois-Rene Rideau <fare@tunes.org> 19970406
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*
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* 4.4BSD (FreeBSD) support added on February 1st 1998 by
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* Niels Kristian Bech Jensen <nkbj@image.dk> partially based
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* on code by Martin von Loewis <martin@mira.isdn.cs.tu-berlin.de>.
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*
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* Migration to usage of "page cache" on May 2006 by
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* Evgeniy Dushistov <dushistov@mail.ru> based on ext2 code base.
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/swap.h>
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#include "ufs_fs.h"
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#include "ufs.h"
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#include "swab.h"
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#include "util.h"
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/*
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* NOTE! unlike strncmp, ufs_match returns 1 for success, 0 for failure.
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*
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* len <= UFS_MAXNAMLEN and de != NULL are guaranteed by caller.
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*/
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static inline int ufs_match(struct super_block *sb, int len,
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const unsigned char *name, struct ufs_dir_entry *de)
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{
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if (len != ufs_get_de_namlen(sb, de))
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return 0;
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if (!de->d_ino)
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return 0;
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return !memcmp(name, de->d_name, len);
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}
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static int ufs_commit_chunk(struct page *page, loff_t pos, unsigned len)
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{
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struct address_space *mapping = page->mapping;
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struct inode *dir = mapping->host;
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int err = 0;
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dir->i_version++;
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block_write_end(NULL, mapping, pos, len, len, page, NULL);
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if (pos+len > dir->i_size) {
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i_size_write(dir, pos+len);
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mark_inode_dirty(dir);
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}
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if (IS_DIRSYNC(dir))
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err = write_one_page(page, 1);
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else
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unlock_page(page);
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return err;
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}
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static inline void ufs_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 ufs_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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ino_t ufs_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 ufs_dir_entry *de;
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struct page *page;
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de = ufs_find_entry(dir, qstr, &page);
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if (de) {
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res = fs32_to_cpu(dir->i_sb, de->d_ino);
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ufs_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 ufs_set_link(struct inode *dir, struct ufs_dir_entry *de,
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struct page *page, struct inode *inode)
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{
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loff_t pos = page_offset(page) +
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(char *) de - (char *) page_address(page);
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unsigned len = fs16_to_cpu(dir->i_sb, de->d_reclen);
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int err;
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lock_page(page);
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err = ufs_prepare_chunk(page, pos, len);
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BUG_ON(err);
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de->d_ino = cpu_to_fs32(dir->i_sb, inode->i_ino);
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ufs_set_de_type(dir->i_sb, de, inode->i_mode);
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err = ufs_commit_chunk(page, pos, len);
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ufs_put_page(page);
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dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
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mark_inode_dirty(dir);
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}
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static void ufs_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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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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const unsigned chunk_mask = UFS_SB(sb)->s_uspi->s_dirblksize - 1;
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struct ufs_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_mask)
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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 - UFS_DIR_REC_LEN(1); offs += rec_len) {
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p = (struct ufs_dir_entry *)(kaddr + offs);
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rec_len = fs16_to_cpu(sb, p->d_reclen);
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if (rec_len < UFS_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 < UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, p)))
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goto Enamelen;
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if (((offs + rec_len - 1) ^ offs) & ~chunk_mask)
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goto Espan;
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if (fs32_to_cpu(sb, p->d_ino) > (UFS_SB(sb)->s_uspi->s_ipg *
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UFS_SB(sb)->s_uspi->s_ncg))
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goto Einumber;
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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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ufs_error(sb, "ufs_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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goto bad_entry;
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Einumber:
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error = "inode out of bounds";
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bad_entry:
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ufs_error (sb, "ufs_check_page", "bad entry in directory #%lu: %s - "
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"offset=%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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rec_len, ufs_get_de_namlen(sb, p));
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goto fail;
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Eend:
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p = (struct ufs_dir_entry *)(kaddr + offs);
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ufs_error(sb, __func__,
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"entry in directory #%lu spans the page boundary"
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"offset=%lu",
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dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs);
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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 *ufs_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 (!PageChecked(page))
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ufs_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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ufs_put_page(page);
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return ERR_PTR(-EIO);
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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
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ufs_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 inline struct ufs_dir_entry *
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ufs_next_entry(struct super_block *sb, struct ufs_dir_entry *p)
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{
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return (struct ufs_dir_entry *)((char *)p +
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fs16_to_cpu(sb, p->d_reclen));
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}
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struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p)
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{
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struct page *page = ufs_get_page(dir, 0);
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struct ufs_dir_entry *de = NULL;
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if (!IS_ERR(page)) {
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de = ufs_next_entry(dir->i_sb,
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(struct ufs_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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/*
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* ufs_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 ufs_dir_entry *ufs_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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struct super_block *sb = dir->i_sb;
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const unsigned char *name = qstr->name;
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int namelen = qstr->len;
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unsigned reclen = UFS_DIR_REC_LEN(namelen);
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unsigned long start, n;
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unsigned long npages = ufs_dir_pages(dir);
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struct page *page = NULL;
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struct ufs_inode_info *ui = UFS_I(dir);
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struct ufs_dir_entry *de;
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UFSD("ENTER, dir_ino %lu, name %s, namlen %u\n", dir->i_ino, name, namelen);
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if (npages == 0 || namelen > UFS_MAXNAMLEN)
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goto out;
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/* OFFSET_CACHE */
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*res_page = NULL;
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start = ui->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 = ufs_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 ufs_dir_entry *) kaddr;
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kaddr += ufs_last_byte(dir, n) - reclen;
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while ((char *) de <= kaddr) {
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if (de->d_reclen == 0) {
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ufs_error(dir->i_sb, __func__,
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"zero-length directory entry");
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ufs_put_page(page);
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goto out;
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}
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if (ufs_match(sb, namelen, name, de))
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goto found;
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de = ufs_next_entry(sb, de);
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}
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ufs_put_page(page);
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}
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if (++n >= npages)
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n = 0;
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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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ui->i_dir_start_lookup = n;
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return de;
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}
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/*
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* Parent is locked.
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*/
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int ufs_add_link(struct dentry *dentry, struct inode *inode)
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{
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struct inode *dir = dentry->d_parent->d_inode;
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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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struct super_block *sb = dir->i_sb;
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unsigned reclen = UFS_DIR_REC_LEN(namelen);
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const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
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unsigned short rec_len, name_len;
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struct page *page = NULL;
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struct ufs_dir_entry *de;
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unsigned long npages = ufs_dir_pages(dir);
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unsigned long n;
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char *kaddr;
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loff_t pos;
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int err;
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UFSD("ENTER, name %s, namelen %u\n", name, namelen);
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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 = ufs_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 + ufs_last_byte(dir, n);
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de = (struct ufs_dir_entry *)kaddr;
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kaddr += PAGE_CACHE_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;
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de->d_reclen = cpu_to_fs16(sb, chunk_size);
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de->d_ino = 0;
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goto got_it;
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}
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if (de->d_reclen == 0) {
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ufs_error(dir->i_sb, __func__,
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"zero-length directory entry");
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err = -EIO;
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goto out_unlock;
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}
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err = -EEXIST;
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if (ufs_match(sb, namelen, name, de))
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goto out_unlock;
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name_len = UFS_DIR_REC_LEN(ufs_get_de_namlen(sb, de));
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rec_len = fs16_to_cpu(sb, de->d_reclen);
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if (!de->d_ino && rec_len >= reclen)
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goto got_it;
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if (rec_len >= name_len + reclen)
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goto got_it;
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de = (struct ufs_dir_entry *) ((char *) de + rec_len);
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}
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unlock_page(page);
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ufs_put_page(page);
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}
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BUG();
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return -EINVAL;
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got_it:
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pos = page_offset(page) +
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(char*)de - (char*)page_address(page);
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err = ufs_prepare_chunk(page, pos, rec_len);
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if (err)
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goto out_unlock;
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if (de->d_ino) {
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struct ufs_dir_entry *de1 =
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(struct ufs_dir_entry *) ((char *) de + name_len);
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de1->d_reclen = cpu_to_fs16(sb, rec_len - name_len);
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de->d_reclen = cpu_to_fs16(sb, name_len);
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de = de1;
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}
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ufs_set_de_namlen(sb, de, namelen);
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memcpy(de->d_name, name, namelen + 1);
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de->d_ino = cpu_to_fs32(sb, inode->i_ino);
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ufs_set_de_type(sb, de, inode->i_mode);
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err = ufs_commit_chunk(page, pos, rec_len);
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dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
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mark_inode_dirty(dir);
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/* OFFSET_CACHE */
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out_put:
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ufs_put_page(page);
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out:
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return err;
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out_unlock:
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unlock_page(page);
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goto out_put;
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}
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static inline unsigned
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ufs_validate_entry(struct super_block *sb, char *base,
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unsigned offset, unsigned mask)
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{
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struct ufs_dir_entry *de = (struct ufs_dir_entry*)(base + offset);
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struct ufs_dir_entry *p = (struct ufs_dir_entry*)(base + (offset&mask));
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while ((char*)p < (char*)de) {
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if (p->d_reclen == 0)
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break;
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p = ufs_next_entry(sb, p);
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}
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return (char *)p - base;
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}
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/*
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* This is blatantly stolen from ext2fs
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*/
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static int
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ufs_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 = file_inode(filp);
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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 = ufs_dir_pages(inode);
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unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
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int need_revalidate = filp->f_version != inode->i_version;
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unsigned flags = UFS_SB(sb)->s_flags;
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UFSD("BEGIN\n");
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if (pos > inode->i_size - UFS_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 ufs_dir_entry *de;
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struct page *page = ufs_get_page(inode, n);
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if (IS_ERR(page)) {
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ufs_error(sb, __func__,
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"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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return -EIO;
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}
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kaddr = page_address(page);
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if (unlikely(need_revalidate)) {
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if (offset) {
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offset = ufs_validate_entry(sb, kaddr, offset, chunk_mask);
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filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
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}
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filp->f_version = inode->i_version;
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need_revalidate = 0;
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}
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de = (struct ufs_dir_entry *)(kaddr+offset);
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limit = kaddr + ufs_last_byte(inode, n) - UFS_DIR_REC_LEN(1);
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for ( ;(char*)de <= limit; de = ufs_next_entry(sb, de)) {
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if (de->d_reclen == 0) {
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ufs_error(sb, __func__,
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"zero-length directory entry");
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ufs_put_page(page);
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return -EIO;
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}
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if (de->d_ino) {
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int over;
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unsigned char d_type = DT_UNKNOWN;
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offset = (char *)de - kaddr;
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UFSD("filldir(%s,%u)\n", de->d_name,
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fs32_to_cpu(sb, de->d_ino));
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UFSD("namlen %u\n", ufs_get_de_namlen(sb, de));
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if ((flags & UFS_DE_MASK) == UFS_DE_44BSD)
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d_type = de->d_u.d_44.d_type;
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over = filldir(dirent, de->d_name,
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ufs_get_de_namlen(sb, de),
|
|
(n<<PAGE_CACHE_SHIFT) | offset,
|
|
fs32_to_cpu(sb, de->d_ino), d_type);
|
|
if (over) {
|
|
ufs_put_page(page);
|
|
return 0;
|
|
}
|
|
}
|
|
filp->f_pos += fs16_to_cpu(sb, de->d_reclen);
|
|
}
|
|
ufs_put_page(page);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* ufs_delete_entry deletes a directory entry by merging it with the
|
|
* previous entry.
|
|
*/
|
|
int ufs_delete_entry(struct inode *inode, struct ufs_dir_entry *dir,
|
|
struct page * page)
|
|
{
|
|
struct super_block *sb = inode->i_sb;
|
|
char *kaddr = page_address(page);
|
|
unsigned from = ((char*)dir - kaddr) & ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
|
|
unsigned to = ((char*)dir - kaddr) + fs16_to_cpu(sb, dir->d_reclen);
|
|
loff_t pos;
|
|
struct ufs_dir_entry *pde = NULL;
|
|
struct ufs_dir_entry *de = (struct ufs_dir_entry *) (kaddr + from);
|
|
int err;
|
|
|
|
UFSD("ENTER\n");
|
|
|
|
UFSD("ino %u, reclen %u, namlen %u, name %s\n",
|
|
fs32_to_cpu(sb, de->d_ino),
|
|
fs16_to_cpu(sb, de->d_reclen),
|
|
ufs_get_de_namlen(sb, de), de->d_name);
|
|
|
|
while ((char*)de < (char*)dir) {
|
|
if (de->d_reclen == 0) {
|
|
ufs_error(inode->i_sb, __func__,
|
|
"zero-length directory entry");
|
|
err = -EIO;
|
|
goto out;
|
|
}
|
|
pde = de;
|
|
de = ufs_next_entry(sb, de);
|
|
}
|
|
if (pde)
|
|
from = (char*)pde - (char*)page_address(page);
|
|
|
|
pos = page_offset(page) + from;
|
|
lock_page(page);
|
|
err = ufs_prepare_chunk(page, pos, to - from);
|
|
BUG_ON(err);
|
|
if (pde)
|
|
pde->d_reclen = cpu_to_fs16(sb, to - from);
|
|
dir->d_ino = 0;
|
|
err = ufs_commit_chunk(page, pos, to - from);
|
|
inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
|
|
mark_inode_dirty(inode);
|
|
out:
|
|
ufs_put_page(page);
|
|
UFSD("EXIT\n");
|
|
return err;
|
|
}
|
|
|
|
int ufs_make_empty(struct inode * inode, struct inode *dir)
|
|
{
|
|
struct super_block * sb = dir->i_sb;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct page *page = grab_cache_page(mapping, 0);
|
|
const unsigned int chunk_size = UFS_SB(sb)->s_uspi->s_dirblksize;
|
|
struct ufs_dir_entry * de;
|
|
char *base;
|
|
int err;
|
|
|
|
if (!page)
|
|
return -ENOMEM;
|
|
|
|
err = ufs_prepare_chunk(page, 0, chunk_size);
|
|
if (err) {
|
|
unlock_page(page);
|
|
goto fail;
|
|
}
|
|
|
|
kmap(page);
|
|
base = (char*)page_address(page);
|
|
memset(base, 0, PAGE_CACHE_SIZE);
|
|
|
|
de = (struct ufs_dir_entry *) base;
|
|
|
|
de->d_ino = cpu_to_fs32(sb, inode->i_ino);
|
|
ufs_set_de_type(sb, de, inode->i_mode);
|
|
ufs_set_de_namlen(sb, de, 1);
|
|
de->d_reclen = cpu_to_fs16(sb, UFS_DIR_REC_LEN(1));
|
|
strcpy (de->d_name, ".");
|
|
de = (struct ufs_dir_entry *)
|
|
((char *)de + fs16_to_cpu(sb, de->d_reclen));
|
|
de->d_ino = cpu_to_fs32(sb, dir->i_ino);
|
|
ufs_set_de_type(sb, de, dir->i_mode);
|
|
de->d_reclen = cpu_to_fs16(sb, chunk_size - UFS_DIR_REC_LEN(1));
|
|
ufs_set_de_namlen(sb, de, 2);
|
|
strcpy (de->d_name, "..");
|
|
kunmap(page);
|
|
|
|
err = ufs_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 ufs_empty_dir(struct inode * inode)
|
|
{
|
|
struct super_block *sb = inode->i_sb;
|
|
struct page *page = NULL;
|
|
unsigned long i, npages = ufs_dir_pages(inode);
|
|
|
|
for (i = 0; i < npages; i++) {
|
|
char *kaddr;
|
|
struct ufs_dir_entry *de;
|
|
page = ufs_get_page(inode, i);
|
|
|
|
if (IS_ERR(page))
|
|
continue;
|
|
|
|
kaddr = page_address(page);
|
|
de = (struct ufs_dir_entry *)kaddr;
|
|
kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1);
|
|
|
|
while ((char *)de <= kaddr) {
|
|
if (de->d_reclen == 0) {
|
|
ufs_error(inode->i_sb, __func__,
|
|
"zero-length directory entry: "
|
|
"kaddr=%p, de=%p\n", kaddr, de);
|
|
goto not_empty;
|
|
}
|
|
if (de->d_ino) {
|
|
u16 namelen=ufs_get_de_namlen(sb, de);
|
|
/* check for . and .. */
|
|
if (de->d_name[0] != '.')
|
|
goto not_empty;
|
|
if (namelen > 2)
|
|
goto not_empty;
|
|
if (namelen < 2) {
|
|
if (inode->i_ino !=
|
|
fs32_to_cpu(sb, de->d_ino))
|
|
goto not_empty;
|
|
} else if (de->d_name[1] != '.')
|
|
goto not_empty;
|
|
}
|
|
de = ufs_next_entry(sb, de);
|
|
}
|
|
ufs_put_page(page);
|
|
}
|
|
return 1;
|
|
|
|
not_empty:
|
|
ufs_put_page(page);
|
|
return 0;
|
|
}
|
|
|
|
const struct file_operations ufs_dir_operations = {
|
|
.read = generic_read_dir,
|
|
.readdir = ufs_readdir,
|
|
.fsync = generic_file_fsync,
|
|
.llseek = generic_file_llseek,
|
|
};
|