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-rw-r--r--fs/minix/dir.c409
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;
+}