From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- fs/minix/dir.c | 409 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 409 insertions(+) create mode 100644 fs/minix/dir.c (limited to 'fs/minix/dir.c') diff --git a/fs/minix/dir.c b/fs/minix/dir.c new file mode 100644 index 00000000000..732502aabc0 --- /dev/null +++ b/fs/minix/dir.c @@ -0,0 +1,409 @@ +/* + * linux/fs/minix/dir.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * minix directory handling functions + */ + +#include "minix.h" +#include +#include + +typedef struct minix_dir_entry minix_dirent; + +static int minix_readdir(struct file *, void *, filldir_t); + +struct file_operations minix_dir_operations = { + .read = generic_read_dir, + .readdir = minix_readdir, + .fsync = minix_sync_file, +}; + +static inline void dir_put_page(struct page *page) +{ + kunmap(page); + page_cache_release(page); +} + +/* + * Return the offset into page `page_nr' of the last valid + * byte in that page, plus one. + */ +static unsigned +minix_last_byte(struct inode *inode, unsigned long page_nr) +{ + unsigned last_byte = PAGE_CACHE_SIZE; + + if (page_nr == (inode->i_size >> PAGE_CACHE_SHIFT)) + last_byte = inode->i_size & (PAGE_CACHE_SIZE - 1); + return last_byte; +} + +static inline unsigned long dir_pages(struct inode *inode) +{ + return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; +} + +static int dir_commit_chunk(struct page *page, unsigned from, unsigned to) +{ + struct inode *dir = (struct inode *)page->mapping->host; + int err = 0; + page->mapping->a_ops->commit_write(NULL, page, from, to); + if (IS_DIRSYNC(dir)) + err = write_one_page(page, 1); + else + unlock_page(page); + return err; +} + +static struct page * dir_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_locked(page); + kmap(page); + if (!PageUptodate(page)) + goto fail; + } + return page; + +fail: + dir_put_page(page); + return ERR_PTR(-EIO); +} + +static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi) +{ + return (void*)((char*)de + sbi->s_dirsize); +} + +static int minix_readdir(struct file * filp, void * dirent, filldir_t filldir) +{ + unsigned long pos = filp->f_pos; + struct inode *inode = filp->f_dentry->d_inode; + 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); + struct minix_sb_info *sbi = minix_sb(sb); + unsigned chunk_size = sbi->s_dirsize; + + lock_kernel(); + + pos = (pos + chunk_size-1) & ~(chunk_size-1); + if (pos >= inode->i_size) + goto done; + + for ( ; n < npages; n++, offset = 0) { + char *p, *kaddr, *limit; + struct page *page = dir_get_page(inode, n); + + if (IS_ERR(page)) + continue; + kaddr = (char *)page_address(page); + p = kaddr+offset; + limit = kaddr + minix_last_byte(inode, n) - chunk_size; + for ( ; p <= limit ; p = minix_next_entry(p, sbi)) { + minix_dirent *de = (minix_dirent *)p; + if (de->inode) { + int over; + unsigned l = strnlen(de->name,sbi->s_namelen); + + offset = p - kaddr; + over = filldir(dirent, de->name, l, + (n<inode, DT_UNKNOWN); + if (over) { + dir_put_page(page); + goto done; + } + } + } + dir_put_page(page); + } + +done: + filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset; + unlock_kernel(); + return 0; +} + +static inline int namecompare(int len, int maxlen, + const char * name, const char * buffer) +{ + if (len < maxlen && buffer[len]) + return 0; + return !memcmp(name, buffer, len); +} + +/* + * minix_find_entry() + * + * finds an entry in the specified directory with the wanted name. It + * returns the cache buffer in which the entry was found, and the entry + * itself (as a parameter - res_dir). It does NOT read the inode of the + * entry - you'll have to do that yourself if you want to. + */ +minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page) +{ + const char * name = dentry->d_name.name; + int namelen = dentry->d_name.len; + struct inode * dir = dentry->d_parent->d_inode; + struct super_block * sb = dir->i_sb; + struct minix_sb_info * sbi = minix_sb(sb); + unsigned long n; + unsigned long npages = dir_pages(dir); + struct page *page = NULL; + struct minix_dir_entry *de; + + *res_page = NULL; + + for (n = 0; n < npages; n++) { + char *kaddr; + page = dir_get_page(dir, n); + if (IS_ERR(page)) + continue; + + kaddr = (char*)page_address(page); + de = (struct minix_dir_entry *) kaddr; + kaddr += minix_last_byte(dir, n) - sbi->s_dirsize; + for ( ; (char *) de <= kaddr ; de = minix_next_entry(de,sbi)) { + if (!de->inode) + continue; + if (namecompare(namelen,sbi->s_namelen,name,de->name)) + goto found; + } + dir_put_page(page); + } + return NULL; + +found: + *res_page = page; + return de; +} + +int minix_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; + struct super_block * sb = dir->i_sb; + struct minix_sb_info * sbi = minix_sb(sb); + struct page *page = NULL; + struct minix_dir_entry * de; + unsigned long npages = dir_pages(dir); + unsigned long n; + char *kaddr; + unsigned from, to; + int err; + + /* + * We take care of directory expansion in the same loop + * This code plays outside i_size, so it locks the page + * to protect that region. + */ + for (n = 0; n <= npages; n++) { + char *dir_end; + + page = dir_get_page(dir, n); + err = PTR_ERR(page); + if (IS_ERR(page)) + goto out; + lock_page(page); + kaddr = (char*)page_address(page); + dir_end = kaddr + minix_last_byte(dir, n); + de = (minix_dirent *)kaddr; + kaddr += PAGE_CACHE_SIZE - sbi->s_dirsize; + while ((char *)de <= kaddr) { + if ((char *)de == dir_end) { + /* We hit i_size */ + de->inode = 0; + goto got_it; + } + if (!de->inode) + goto got_it; + err = -EEXIST; + if (namecompare(namelen,sbi->s_namelen,name,de->name)) + goto out_unlock; + de = minix_next_entry(de, sbi); + } + unlock_page(page); + dir_put_page(page); + } + BUG(); + return -EINVAL; + +got_it: + from = (char*)de - (char*)page_address(page); + to = from + sbi->s_dirsize; + err = page->mapping->a_ops->prepare_write(NULL, page, from, to); + if (err) + goto out_unlock; + memcpy (de->name, name, namelen); + memset (de->name + namelen, 0, sbi->s_dirsize - namelen - 2); + de->inode = inode->i_ino; + err = dir_commit_chunk(page, from, to); + dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty(dir); +out_put: + dir_put_page(page); +out: + return err; +out_unlock: + unlock_page(page); + goto out_put; +} + +int minix_delete_entry(struct minix_dir_entry *de, struct page *page) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = (struct inode*)mapping->host; + char *kaddr = page_address(page); + unsigned from = (char*)de - kaddr; + unsigned to = from + minix_sb(inode->i_sb)->s_dirsize; + int err; + + lock_page(page); + err = mapping->a_ops->prepare_write(NULL, page, from, to); + if (err == 0) { + de->inode = 0; + err = dir_commit_chunk(page, from, to); + } else { + unlock_page(page); + } + dir_put_page(page); + inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; + mark_inode_dirty(inode); + return err; +} + +int minix_make_empty(struct inode *inode, struct inode *dir) +{ + struct address_space *mapping = inode->i_mapping; + struct page *page = grab_cache_page(mapping, 0); + struct minix_sb_info * sbi = minix_sb(inode->i_sb); + struct minix_dir_entry * de; + char *kaddr; + int err; + + if (!page) + return -ENOMEM; + err = mapping->a_ops->prepare_write(NULL, page, 0, 2 * sbi->s_dirsize); + if (err) { + unlock_page(page); + goto fail; + } + + kaddr = kmap_atomic(page, KM_USER0); + memset(kaddr, 0, PAGE_CACHE_SIZE); + + de = (struct minix_dir_entry *)kaddr; + de->inode = inode->i_ino; + strcpy(de->name,"."); + de = minix_next_entry(de, sbi); + de->inode = dir->i_ino; + strcpy(de->name,".."); + kunmap_atomic(kaddr, KM_USER0); + + err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize); +fail: + page_cache_release(page); + return err; +} + +/* + * routine to check that the specified directory is empty (for rmdir) + */ +int minix_empty_dir(struct inode * inode) +{ + struct page *page = NULL; + unsigned long i, npages = dir_pages(inode); + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + + for (i = 0; i < npages; i++) { + char *kaddr; + minix_dirent * de; + page = dir_get_page(inode, i); + + if (IS_ERR(page)) + continue; + + kaddr = (char *)page_address(page); + de = (minix_dirent *)kaddr; + kaddr += minix_last_byte(inode, i) - sbi->s_dirsize; + + while ((char *)de <= kaddr) { + if (de->inode != 0) { + /* check for . and .. */ + if (de->name[0] != '.') + goto not_empty; + if (!de->name[1]) { + if (de->inode != inode->i_ino) + goto not_empty; + } else if (de->name[1] != '.') + goto not_empty; + else if (de->name[2]) + goto not_empty; + } + de = minix_next_entry(de, sbi); + } + dir_put_page(page); + } + return 1; + +not_empty: + dir_put_page(page); + return 0; +} + +/* Releases the page */ +void minix_set_link(struct minix_dir_entry *de, struct page *page, + struct inode *inode) +{ + struct inode *dir = (struct inode*)page->mapping->host; + struct minix_sb_info *sbi = minix_sb(dir->i_sb); + unsigned from = (char *)de-(char*)page_address(page); + unsigned to = from + sbi->s_dirsize; + int err; + + lock_page(page); + err = page->mapping->a_ops->prepare_write(NULL, page, from, to); + if (err == 0) { + de->inode = inode->i_ino; + err = dir_commit_chunk(page, from, to); + } else { + unlock_page(page); + } + dir_put_page(page); + dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty(dir); +} + +struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p) +{ + struct page *page = dir_get_page(dir, 0); + struct minix_sb_info *sbi = minix_sb(dir->i_sb); + struct minix_dir_entry *de = NULL; + + if (!IS_ERR(page)) { + de = minix_next_entry(page_address(page), sbi); + *p = page; + } + return de; +} + +ino_t minix_inode_by_name(struct dentry *dentry) +{ + struct page *page; + struct minix_dir_entry *de = minix_find_entry(dentry, &page); + ino_t res = 0; + + if (de) { + res = de->inode; + dir_put_page(page); + } + return res; +} -- cgit v1.2.3