+++ /dev/null
-/*
- * linux/fs/ext2/dir.c
- *
- * Copyright (C) 1992, 1993, 1994, 1995
- * Remy Card (card@masi.ibp.fr)
- * Laboratoire MASI - Institut Blaise Pascal
- * Universite Pierre et Marie Curie (Paris VI)
- *
- * from
- *
- * linux/fs/minix/dir.c
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- *
- * ext2 directory handling functions
- *
- * Big-endian to little-endian byte-swapping/bitmaps by
- * David S. Miller (davem@caip.rutgers.edu), 1995
- *
- * All code that works with directory layout had been switched to pagecache
- * and moved here. AV
- */
-
-#include <linux/fs.h>
-#include <linux/ext2_fs.h>
-#include <linux/pagemap.h>
-
-#define DEBUG_SUBSYSTEM S_OBDFS
-
-#include <linux/obd_support.h>
-#include <linux/locks.h>
-
-typedef struct ext2_dir_entry_2 ext2_dirent;
-
-#define PageChecked(page) test_bit(PG_checked, &(page)->flags)
-#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
-
-int waitfor_one_page(struct page *page)
-{
- int error = 0;
- struct buffer_head *bh, *head = page->buffers;
-
- bh = head;
- do {
- wait_on_buffer(bh);
- if (buffer_req(bh) && !buffer_uptodate(bh))
- error = -EIO;
- } while ((bh = bh->b_this_page) != head);
- return error;
-}
-
-/*
- * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
- * more robust, but we have what we have
- */
-static inline unsigned ext2_chunk_size(struct inode *inode)
-{
- //return inode->i_sb->s_blocksize;
- return PAGE_SIZE;
-}
-
-static inline void ext2_put_page(struct page *page)
-{
- kunmap(page);
- page_cache_release(page);
-}
-
-static inline unsigned long dir_pages(struct inode *inode)
-{
- return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
-}
-
-static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to)
-{
- struct inode *dir = page->mapping->host;
- int err = 0;
- dir->i_version = ++event;
- page->mapping->a_ops->commit_write(NULL, page, from, to);
- if (IS_SYNC(dir))
- err = waitfor_one_page(page);
- return err;
-}
-
-static void ext2_check_page(struct page *page)
-{
- struct inode *dir = page->mapping->host;
- unsigned chunk_size = ext2_chunk_size(dir);
- char *kaddr = page_address(page);
- // u32 max_inumber = le32_to_cpu(sb->u.ext2_sb.s_es->s_inodes_count);
- unsigned offs, rec_len;
- unsigned limit = PAGE_CACHE_SIZE;
- ext2_dirent *p;
- char *error;
-
- if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
- limit = dir->i_size & ~PAGE_CACHE_MASK;
- if (limit & (chunk_size - 1))
- goto Ebadsize;
- for (offs = limit; offs<PAGE_CACHE_SIZE; offs += chunk_size) {
- ext2_dirent *p = (ext2_dirent*)(kaddr + offs);
- p->rec_len = cpu_to_le16(chunk_size);
- }
- if (!limit)
- goto out;
- }
- for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
- p = (ext2_dirent *)(kaddr + offs);
- rec_len = le16_to_cpu(p->rec_len);
-
- if (rec_len < EXT2_DIR_REC_LEN(1))
- goto Eshort;
- if (rec_len & 3)
- goto Ealign;
- if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
- goto Enamelen;
- if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
- goto Espan;
- // if (le32_to_cpu(p->inode) > max_inumber)
- //goto Einumber;
- }
- if (offs != limit)
- goto Eend;
-out:
- SetPageChecked(page);
- return;
-
- /* Too bad, we had an error */
-
-Ebadsize:
- CERROR("ext2_check_page"
- "size of directory #%lu is not a multiple of chunk size",
- dir->i_ino
- );
- goto fail;
-Eshort:
- error = "rec_len is smaller than minimal";
- goto bad_entry;
-Ealign:
- error = "unaligned directory entry";
- goto bad_entry;
-Enamelen:
- error = "rec_len is too small for name_len";
- goto bad_entry;
-Espan:
- error = "directory entry across blocks";
- goto bad_entry;
- //Einumber:
- // error = "inode out of bounds";
-bad_entry:
- CERROR("ext2_check_page" "bad entry in directory #%lu: %s - "
- "offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
- dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
- (unsigned long) le32_to_cpu(p->inode),
- rec_len, p->name_len);
- goto fail;
-Eend:
- p = (ext2_dirent *)(kaddr + offs);
- CERROR("ext2_check_page"
- "entry in directory #%lu spans the page boundary"
- "offset=%lu, inode=%lu",
- dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
- (unsigned long) le32_to_cpu(p->inode));
-fail:
- SetPageChecked(page);
- SetPageError(page);
-}
-
-static struct page * ext2_get_page(struct inode *dir, unsigned long n)
-{
- struct address_space *mapping = dir->i_mapping;
- struct page *page = read_cache_page(mapping, n,
- (filler_t*)mapping->a_ops->readpage, NULL);
- if (!IS_ERR(page)) {
- wait_on_page(page);
- kmap(page);
- if (!Page_Uptodate(page))
- goto fail;
- if (!PageChecked(page))
- ext2_check_page(page);
- if (PageError(page))
- goto fail;
- }
- return page;
-
-fail:
- ext2_put_page(page);
- return ERR_PTR(-EIO);
-}
-
-/*
- * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
- *
- * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
- */
-static inline int ext2_match (int len, const char * const name,
- struct ext2_dir_entry_2 * de)
-{
- if (len != de->name_len)
- return 0;
- if (!de->inode)
- return 0;
- return !memcmp(name, de->name, len);
-}
-
-/*
- * p is at least 6 bytes before the end of page
- */
-static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
-{
- return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len));
-}
-
-static inline unsigned
-ext2_validate_entry(char *base, unsigned offset, unsigned mask)
-{
- ext2_dirent *de = (ext2_dirent*)(base + offset);
- ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
- while ((char*)p < (char*)de)
- p = ext2_next_entry(p);
- return (char *)p - base;
-}
-
-static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
- [EXT2_FT_UNKNOWN] DT_UNKNOWN,
- [EXT2_FT_REG_FILE] DT_REG,
- [EXT2_FT_DIR] DT_DIR,
- [EXT2_FT_CHRDEV] DT_CHR,
- [EXT2_FT_BLKDEV] DT_BLK,
- [EXT2_FT_FIFO] DT_FIFO,
- [EXT2_FT_SOCK] DT_SOCK,
- [EXT2_FT_SYMLINK] DT_LNK,
-};
-
-static unsigned int obdfs_dt2fmt[DT_WHT + 1] = {
- [EXT2_FT_UNKNOWN] 0,
- [EXT2_FT_REG_FILE] S_IFREG,
- [EXT2_FT_DIR] S_IFDIR,
- [EXT2_FT_CHRDEV] S_IFCHR,
- [EXT2_FT_BLKDEV] S_IFBLK,
- [EXT2_FT_FIFO] S_IFIFO,
- [EXT2_FT_SOCK] S_IFSOCK,
- [EXT2_FT_SYMLINK] S_IFLNK
-};
-
-#define S_SHIFT 12
-static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
- [S_IFREG >> S_SHIFT] EXT2_FT_REG_FILE,
- [S_IFDIR >> S_SHIFT] EXT2_FT_DIR,
- [S_IFCHR >> S_SHIFT] EXT2_FT_CHRDEV,
- [S_IFBLK >> S_SHIFT] EXT2_FT_BLKDEV,
- [S_IFIFO >> S_SHIFT] EXT2_FT_FIFO,
- [S_IFSOCK >> S_SHIFT] EXT2_FT_SOCK,
- [S_IFLNK >> S_SHIFT] EXT2_FT_SYMLINK,
-};
-
-static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
-{
- mode_t mode = inode->i_mode;
- de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
-}
-
-int
-new_obdfs_readdir (struct file * filp, void * dirent, filldir_t filldir)
-{
- loff_t pos = filp->f_pos;
- struct inode *inode = filp->f_dentry->d_inode;
- // XXX struct super_block *sb = inode->i_sb;
- unsigned offset = pos & ~PAGE_CACHE_MASK;
- unsigned long n = pos >> PAGE_CACHE_SHIFT;
- unsigned long npages = dir_pages(inode);
- unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
- unsigned char *types = NULL;
- int need_revalidate = (filp->f_version != inode->i_version);
-
- if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
- goto done;
-
- types = ext2_filetype_table;
-
- for ( ; n < npages; n++, offset = 0) {
- char *kaddr, *limit;
- ext2_dirent *de;
- struct page *page = ext2_get_page(inode, n);
-
- if (IS_ERR(page))
- continue;
- kaddr = page_address(page);
- if (need_revalidate) {
- offset = ext2_validate_entry(kaddr, offset, chunk_mask);
- need_revalidate = 0;
- }
- de = (ext2_dirent *)(kaddr+offset);
- limit = kaddr + PAGE_CACHE_SIZE - EXT2_DIR_REC_LEN(1);
- for ( ;(char*)de <= limit; de = ext2_next_entry(de))
- if (de->inode) {
- int over;
- unsigned char d_type = DT_UNKNOWN;
-
- if (types && de->file_type < EXT2_FT_MAX)
- d_type = types[de->file_type];
-
- offset = (char *)de - kaddr;
- over = filldir(dirent, de->name, de->name_len,
- (n<<PAGE_CACHE_SHIFT) | offset,
- le32_to_cpu(de->inode), d_type);
- if (over) {
- ext2_put_page(page);
- goto done;
- }
- }
- ext2_put_page(page);
- }
-
-done:
- filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
- filp->f_version = inode->i_version;
- UPDATE_ATIME(inode);
- return 0;
-}
-
-/*
- * ext2_find_entry()
- *
- * finds an entry in the specified directory with the wanted name. It
- * returns the page in which the entry was found, and the entry itself
- * (as a parameter - res_dir). Page is returned mapped and unlocked.
- * Entry is guaranteed to be valid.
- */
-struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
- struct dentry *dentry, struct page ** res_page)
-{
- const char *name = dentry->d_name.name;
- int namelen = dentry->d_name.len;
- unsigned reclen = EXT2_DIR_REC_LEN(namelen);
- unsigned long start, n;
- unsigned long npages = dir_pages(dir);
- struct page *page = NULL;
- ext2_dirent * de;
-
- /* OFFSET_CACHE */
- *res_page = NULL;
-
- // start = dir->u.ext2_i.i_dir_start_lookup;
- start = 0;
- if (start >= npages)
- start = 0;
- n = start;
- do {
- char *kaddr;
- page = ext2_get_page(dir, n);
- if (!IS_ERR(page)) {
- kaddr = page_address(page);
- de = (ext2_dirent *) kaddr;
- kaddr += PAGE_CACHE_SIZE - reclen;
- while ((char *) de <= kaddr) {
- if (ext2_match (namelen, name, de))
- goto found;
- de = ext2_next_entry(de);
- }
- ext2_put_page(page);
- }
- if (++n >= npages)
- n = 0;
- } while (n != start);
- return NULL;
-
-found:
- *res_page = page;
- // dir->u.ext2_i.i_dir_start_lookup = n;
- return de;
-}
-
-struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
-{
- struct page *page = ext2_get_page(dir, 0);
- ext2_dirent *de = NULL;
-
- if (!IS_ERR(page)) {
- de = ext2_next_entry((ext2_dirent *) page_address(page));
- *p = page;
- }
- return de;
-}
-
-ino_t obdfs_inode_by_name(struct inode * dir, struct dentry *dentry, int *type)
-{
- ino_t res = 0;
- struct ext2_dir_entry_2 * de;
- struct page *page;
-
- de = ext2_find_entry (dir, dentry, &page);
- if (de) {
- res = le32_to_cpu(de->inode);
- *type = obdfs_dt2fmt[de->file_type];
- kunmap(page);
- page_cache_release(page);
- }
- return res;
-}
-
-/* Releases the page */
-void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
- struct page *page, struct inode *inode)
-{
- unsigned from = (char *) de - (char *) page_address(page);
- unsigned to = from + le16_to_cpu(de->rec_len);
- int err;
-
- lock_page(page);
- err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
- if (err)
- LBUG();
- de->inode = cpu_to_le32(inode->i_ino);
- ext2_set_de_type (de, inode);
- dir->i_mtime = dir->i_ctime = CURRENT_TIME;
- err = ext2_commit_chunk(page, from, to);
- UnlockPage(page);
- ext2_put_page(page);
-}
-
-/*
- * Parent is locked.
- */
-int ext2_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 reclen = EXT2_DIR_REC_LEN(namelen);
- unsigned short rec_len, name_len;
- struct page *page = NULL;
- ext2_dirent * de;
- unsigned long npages = dir_pages(dir);
- unsigned long n;
- char *kaddr;
- unsigned from, to;
- int err;
-
- /* We take care of directory expansion in the same loop */
- for (n = 0; n <= npages; n++) {
- page = ext2_get_page(dir, n);
- err = PTR_ERR(page);
- if (IS_ERR(page))
- goto out;
- kaddr = page_address(page);
- de = (ext2_dirent *)kaddr;
- kaddr += PAGE_CACHE_SIZE - reclen;
- while ((char *)de <= kaddr) {
- err = -EEXIST;
- if (ext2_match (namelen, name, de))
- goto out_page;
- name_len = EXT2_DIR_REC_LEN(de->name_len);
- rec_len = le16_to_cpu(de->rec_len);
- if ( n==npages && rec_len == 0) {
- CERROR("Fatal dir behaviour\n");
- goto out_page;
- }
- if (!de->inode && rec_len >= reclen)
- goto got_it;
- if (rec_len >= name_len + reclen)
- goto got_it;
- de = (ext2_dirent *) ((char *) de + rec_len);
- }
- ext2_put_page(page);
- }
- LBUG();
- return -EINVAL;
-
-got_it:
- from = (char*)de - (char*)page_address(page);
- to = from + rec_len;
- lock_page(page);
- err = page->mapping->a_ops->prepare_write(NULL, page, from, to);
- if (err)
- goto out_unlock;
- if (de->inode) {
- ext2_dirent *de1 = (ext2_dirent *) ((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_le32(inode->i_ino);
- ext2_set_de_type (de, inode);
- CDEBUG(D_INODE, "type set to %o\n", de->file_type);
- dir->i_mtime = dir->i_ctime = CURRENT_TIME;
- err = ext2_commit_chunk(page, from, to);
-
- // change_inode happens with the commit_chunk
- // obdfs_change_inode(dir);
- /* OFFSET_CACHE */
-out_unlock:
- UnlockPage(page);
-out_page:
- ext2_put_page(page);
-out:
- return err;
-}
-
-/*
- * ext2_delete_entry deletes a directory entry by merging it with the
- * previous entry. Page is up-to-date. Releases the page.
- */
-int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
-{
- struct address_space *mapping = page->mapping;
- struct inode *inode = mapping->host;
- char *kaddr = page_address(page);
- unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
- unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len);
- ext2_dirent * pde = NULL;
- ext2_dirent * de = (ext2_dirent *) (kaddr + from);
- int err;
-
- while ((char*)de < (char*)dir) {
- pde = de;
- de = ext2_next_entry(de);
- }
- if (pde)
- from = (char*)pde - (char*)page_address(page);
- lock_page(page);
- err = mapping->a_ops->prepare_write(NULL, page, from, to);
- if (err)
- LBUG();
- if (pde)
- pde->rec_len = cpu_to_le16(to-from);
- dir->inode = 0;
- inode->i_ctime = inode->i_mtime = CURRENT_TIME;
- err = ext2_commit_chunk(page, from, to);
- UnlockPage(page);
- ext2_put_page(page);
- return err;
-}
-
-/*
- * Set the first fragment of directory.
- */
-int ext2_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 = ext2_chunk_size(inode);
- struct ext2_dir_entry_2 * de;
- char *base;
- int err;
- ENTRY;
-
- if (!page)
- return -ENOMEM;
- err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size);
- if (err)
- goto fail;
-
- base = page_address(page);
-
- de = (struct ext2_dir_entry_2 *) base;
- de->name_len = 1;
- de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1));
- memcpy (de->name, ".\0\0", 4);
- de->inode = cpu_to_le32(inode->i_ino);
- ext2_set_de_type (de, inode);
-
- de = (struct ext2_dir_entry_2 *) (base + EXT2_DIR_REC_LEN(1));
- de->name_len = 2;
- de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1));
- de->inode = cpu_to_le32(parent->i_ino);
- memcpy (de->name, "..\0", 4);
- ext2_set_de_type (de, inode);
-
- err = ext2_commit_chunk(page, 0, chunk_size);
-fail:
- UnlockPage(page);
- page_cache_release(page);
- ENTRY;
- return err;
-}
-
-/*
- * routine to check that the specified directory is empty (for rmdir)
- */
-int ext2_empty_dir (struct inode * inode)
-{
- struct page *page = NULL;
- unsigned long i, npages = dir_pages(inode);
-
- for (i = 0; i < npages; i++) {
- char *kaddr;
- ext2_dirent * de;
- page = ext2_get_page(inode, i);
-
- if (IS_ERR(page))
- continue;
-
- kaddr = page_address(page);
- de = (ext2_dirent *)kaddr;
- kaddr += PAGE_CACHE_SIZE-EXT2_DIR_REC_LEN(1);
-
- while ((char *)de <= kaddr) {
- if (de->inode != 0) {
- /* check for . and .. */
- if (de->name[0] != '.')
- goto not_empty;
- if (de->name_len > 2)
- goto not_empty;
- if (de->name_len < 2) {
- if (de->inode !=
- cpu_to_le32(inode->i_ino))
- goto not_empty;
- } else if (de->name[1] != '.')
- goto not_empty;
- }
- de = ext2_next_entry(de);
- }
- ext2_put_page(page);
- }
- return 1;
-
-not_empty:
- ext2_put_page(page);
- return 0;
-}
-
-struct file_operations obdfs_dir_operations = {
- read: generic_read_dir,
- readdir: new_obdfs_readdir
-};
git://git.whamcloud.com / fs / lustre-release.git / blobdiff