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/sysv/dir.c | 388 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 388 insertions(+) create mode 100644 fs/sysv/dir.c (limited to 'fs/sysv/dir.c') diff --git a/fs/sysv/dir.c b/fs/sysv/dir.c new file mode 100644 index 0000000..69a085a --- /dev/null +++ b/fs/sysv/dir.c @@ -0,0 +1,388 @@ +/* + * linux/fs/sysv/dir.c + * + * minix/dir.c + * Copyright (C) 1991, 1992 Linus Torvalds + * + * coh/dir.c + * Copyright (C) 1993 Pascal Haible, Bruno Haible + * + * sysv/dir.c + * Copyright (C) 1993 Bruno Haible + * + * SystemV/Coherent directory handling functions + */ + +#include +#include +#include +#include "sysv.h" + +static int sysv_readdir(struct file *, void *, filldir_t); + +struct file_operations sysv_dir_operations = { + .read = generic_read_dir, + .readdir = sysv_readdir, + .fsync = sysv_sync_file, +}; + +static inline void dir_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 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 int sysv_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); + + lock_kernel(); + + pos = (pos + SYSV_DIRSIZE-1) & ~(SYSV_DIRSIZE-1); + if (pos >= inode->i_size) + goto done; + + for ( ; n < npages; n++, offset = 0) { + char *kaddr, *limit; + struct sysv_dir_entry *de; + struct page *page = dir_get_page(inode, n); + + if (IS_ERR(page)) + continue; + kaddr = (char *)page_address(page); + de = (struct sysv_dir_entry *)(kaddr+offset); + limit = kaddr + PAGE_CACHE_SIZE - SYSV_DIRSIZE; + for ( ;(char*)de <= limit; de++) { + char *name = de->name; + int over; + + if (!de->inode) + continue; + + offset = (char *)de - kaddr; + + over = filldir(dirent, name, strnlen(name,SYSV_NAMELEN), + (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; +} + +/* compare strings: name[0..len-1] (not zero-terminated) and + * buffer[0..] (filled with zeroes up to buffer[0..maxlen-1]) + */ +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); +} + +/* + * sysv_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. + */ +struct sysv_dir_entry *sysv_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; + unsigned long start, n; + unsigned long npages = dir_pages(dir); + struct page *page = NULL; + struct sysv_dir_entry *de; + + *res_page = NULL; + + start = SYSV_I(dir)->i_dir_start_lookup; + if (start >= npages) + start = 0; + n = start; + + do { + char *kaddr; + page = dir_get_page(dir, n); + if (!IS_ERR(page)) { + kaddr = (char*)page_address(page); + de = (struct sysv_dir_entry *) kaddr; + kaddr += PAGE_CACHE_SIZE - SYSV_DIRSIZE; + for ( ; (char *) de <= kaddr ; de++) { + if (!de->inode) + continue; + if (namecompare(namelen, SYSV_NAMELEN, + name, de->name)) + goto found; + } + } + dir_put_page(page); + + if (++n >= npages) + n = 0; + } while (n != start); + + return NULL; + +found: + SYSV_I(dir)->i_dir_start_lookup = n; + *res_page = page; + return de; +} + +int sysv_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 page *page = NULL; + struct sysv_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 */ + for (n = 0; n <= npages; n++) { + page = dir_get_page(dir, n); + err = PTR_ERR(page); + if (IS_ERR(page)) + goto out; + kaddr = (char*)page_address(page); + de = (struct sysv_dir_entry *)kaddr; + kaddr += PAGE_CACHE_SIZE - SYSV_DIRSIZE; + while ((char *)de <= kaddr) { + if (!de->inode) + goto got_it; + err = -EEXIST; + if (namecompare(namelen, SYSV_NAMELEN, name, de->name)) + goto out_page; + de++; + } + dir_put_page(page); + } + BUG(); + return -EINVAL; + +got_it: + from = (char*)de - (char*)page_address(page); + to = from + SYSV_DIRSIZE; + lock_page(page); + 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, SYSV_DIRSIZE - namelen - 2); + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino); + err = dir_commit_chunk(page, from, to); + dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty(dir); +out_page: + dir_put_page(page); +out: + return err; +out_unlock: + unlock_page(page); + goto out_page; +} + +int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page) +{ + struct address_space *mapping = page->mapping; + struct inode *inode = (struct inode*)mapping->host; + char *kaddr = (char*)page_address(page); + unsigned from = (char*)de - kaddr; + unsigned to = from + SYSV_DIRSIZE; + int err; + + lock_page(page); + err = mapping->a_ops->prepare_write(NULL, page, from, to); + if (err) + BUG(); + de->inode = 0; + err = dir_commit_chunk(page, from, to); + dir_put_page(page); + inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; + mark_inode_dirty(inode); + return err; +} + +int sysv_make_empty(struct inode *inode, struct inode *dir) +{ + struct address_space *mapping = inode->i_mapping; + struct page *page = grab_cache_page(mapping, 0); + struct sysv_dir_entry * de; + char *base; + int err; + + if (!page) + return -ENOMEM; + kmap(page); + err = mapping->a_ops->prepare_write(NULL, page, 0, 2 * SYSV_DIRSIZE); + if (err) { + unlock_page(page); + goto fail; + } + + base = (char*)page_address(page); + memset(base, 0, PAGE_CACHE_SIZE); + + de = (struct sysv_dir_entry *) base; + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino); + strcpy(de->name,"."); + de++; + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), dir->i_ino); + strcpy(de->name,".."); + + err = dir_commit_chunk(page, 0, 2 * SYSV_DIRSIZE); +fail: + kunmap(page); + page_cache_release(page); + return err; +} + +/* + * routine to check that the specified directory is empty (for rmdir) + */ +int sysv_empty_dir(struct inode * inode) +{ + struct super_block *sb = inode->i_sb; + struct page *page = NULL; + unsigned long i, npages = dir_pages(inode); + + for (i = 0; i < npages; i++) { + char *kaddr; + struct sysv_dir_entry * de; + page = dir_get_page(inode, i); + + if (IS_ERR(page)) + continue; + + kaddr = (char *)page_address(page); + de = (struct sysv_dir_entry *)kaddr; + kaddr += PAGE_CACHE_SIZE-SYSV_DIRSIZE; + + for ( ;(char *)de <= kaddr; de++) { + if (!de->inode) + continue; + /* check for . and .. */ + if (de->name[0] != '.') + goto not_empty; + if (!de->name[1]) { + if (de->inode == cpu_to_fs16(SYSV_SB(sb), + inode->i_ino)) + continue; + goto not_empty; + } + if (de->name[1] != '.' || de->name[2]) + goto not_empty; + } + dir_put_page(page); + } + return 1; + +not_empty: + dir_put_page(page); + return 0; +} + +/* Releases the page */ +void sysv_set_link(struct sysv_dir_entry *de, struct page *page, + struct inode *inode) +{ + struct inode *dir = (struct inode*)page->mapping->host; + unsigned from = (char *)de-(char*)page_address(page); + unsigned to = from + SYSV_DIRSIZE; + int err; + + lock_page(page); + err = page->mapping->a_ops->prepare_write(NULL, page, from, to); + if (err) + BUG(); + de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino); + err = dir_commit_chunk(page, from, to); + dir_put_page(page); + dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty(dir); +} + +struct sysv_dir_entry * sysv_dotdot (struct inode *dir, struct page **p) +{ + struct page *page = dir_get_page(dir, 0); + struct sysv_dir_entry *de = NULL; + + if (!IS_ERR(page)) { + de = (struct sysv_dir_entry*) page_address(page) + 1; + *p = page; + } + return de; +} + +ino_t sysv_inode_by_name(struct dentry *dentry) +{ + struct page *page; + struct sysv_dir_entry *de = sysv_find_entry (dentry, &page); + ino_t res = 0; + + if (de) { + res = fs16_to_cpu(SYSV_SB(dentry->d_sb), de->inode); + dir_put_page(page); + } + return res; +} -- cgit v1.1