1 files changed, 409 insertions, 0 deletions

diff --git a/fs/minix/dir.c b/fs/minix/dir.c
new file mode 100644
index 000000000000..732502aabc05
--- /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 <linux/highmem.h>
+#include <linux/smp_lock.h>
+
+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<<PAGE_CACHE_SHIFT) | offset,
+                                                de->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;
+}