--- /dev/null
+/*
+ * Copyright (c) 2000-2001 Christoph Hellwig.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions, and the following disclaimer,
+ * without modification.
+ * 2. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL").
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Veritas filesystem driver - lookup and other directory related code.
+ */
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/kernel.h>
+#include <linux/pagemap.h>
+
+#include "vxfs.h"
+#include "vxfs_dir.h"
+#include "vxfs_inode.h"
+#include "vxfs_extern.h"
+
+/*
+ * Number of VxFS blocks per page.
+ */
+#define VXFS_BLOCK_PER_PAGE(sbp) ((PAGE_CACHE_SIZE / (sbp)->s_blocksize))
+
+
+static struct dentry * vxfs_lookup(struct inode *, struct dentry *, unsigned int);
+static int vxfs_readdir(struct file *, struct dir_context *);
+
+const struct inode_operations vxfs_dir_inode_ops = {
+ .lookup = vxfs_lookup,
+};
+
+const struct file_operations vxfs_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate = vxfs_readdir,
+};
+
+
+static inline u_long
+dir_pages(struct inode *inode)
+{
+ return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+}
+
+static inline u_long
+dir_blocks(struct inode *ip)
+{
+ u_long bsize = ip->i_sb->s_blocksize;
+ return (ip->i_size + bsize - 1) & ~(bsize - 1);
+}
+
+/*
+ * NOTE! unlike strncmp, vxfs_match returns 1 for success, 0 for failure.
+ *
+ * len <= VXFS_NAMELEN and de != NULL are guaranteed by caller.
+ */
+static inline int
+vxfs_match(int len, const char * const name, struct vxfs_direct *de)
+{
+ if (len != de->d_namelen)
+ return 0;
+ if (!de->d_ino)
+ return 0;
+ return !memcmp(name, de->d_name, len);
+}
+
+static inline struct vxfs_direct *
+vxfs_next_entry(struct vxfs_direct *de)
+{
+ return ((struct vxfs_direct *)((char*)de + de->d_reclen));
+}
+
+/**
+ * vxfs_find_entry - find a mathing directory entry for a dentry
+ * @ip: directory inode
+ * @dp: dentry for which we want to find a direct
+ * @ppp: gets filled with the page the return value sits in
+ *
+ * Description:
+ * vxfs_find_entry finds a &struct vxfs_direct for the VFS directory
+ * cache entry @dp. @ppp will be filled with the page the return
+ * value resides in.
+ *
+ * Returns:
+ * The wanted direct on success, else a NULL pointer.
+ */
+static struct vxfs_direct *
+vxfs_find_entry(struct inode *ip, struct dentry *dp, struct page **ppp)
+{
+ u_long npages, page, nblocks, pblocks, block;
+ u_long bsize = ip->i_sb->s_blocksize;
+ const char *name = dp->d_name.name;
+ int namelen = dp->d_name.len;
+
+ npages = dir_pages(ip);
+ nblocks = dir_blocks(ip);
+ pblocks = VXFS_BLOCK_PER_PAGE(ip->i_sb);
+
+ for (page = 0; page < npages; page++) {
+ caddr_t kaddr;
+ struct page *pp;
+
+ pp = vxfs_get_page(ip->i_mapping, page);
+ if (IS_ERR(pp))
+ continue;
+ kaddr = (caddr_t)page_address(pp);
+
+ for (block = 0; block <= nblocks && block <= pblocks; block++) {
+ caddr_t baddr, limit;
+ struct vxfs_dirblk *dbp;
+ struct vxfs_direct *de;
+
+ baddr = kaddr + (block * bsize);
+ limit = baddr + bsize - VXFS_DIRLEN(1);
+
+ dbp = (struct vxfs_dirblk *)baddr;
+ de = (struct vxfs_direct *)(baddr + VXFS_DIRBLKOV(dbp));
+
+ for (; (caddr_t)de <= limit; de = vxfs_next_entry(de)) {
+ if (!de->d_reclen)
+ break;
+ if (!de->d_ino)
+ continue;
+ if (vxfs_match(namelen, name, de)) {
+ *ppp = pp;
+ return (de);
+ }
+ }
+ }
+ vxfs_put_page(pp);
+ }
+
+ return NULL;
+}
+
+/**
+ * vxfs_inode_by_name - find inode number for dentry
+ * @dip: directory to search in
+ * @dp: dentry we search for
+ *
+ * Description:
+ * vxfs_inode_by_name finds out the inode number of
+ * the path component described by @dp in @dip.
+ *
+ * Returns:
+ * The wanted inode number on success, else Zero.
+ */
+static ino_t
+vxfs_inode_by_name(struct inode *dip, struct dentry *dp)
+{
+ struct vxfs_direct *de;
+ struct page *pp;
+ ino_t ino = 0;
+
+ de = vxfs_find_entry(dip, dp, &pp);
+ if (de) {
+ ino = de->d_ino;
+ kunmap(pp);
+ page_cache_release(pp);
+ }
+
+ return (ino);
+}
+
+/**
+ * vxfs_lookup - lookup pathname component
+ * @dip: dir in which we lookup
+ * @dp: dentry we lookup
+ * @flags: lookup flags
+ *
+ * Description:
+ * vxfs_lookup tries to lookup the pathname component described
+ * by @dp in @dip.
+ *
+ * Returns:
+ * A NULL-pointer on success, else an negative error code encoded
+ * in the return pointer.
+ */
+static struct dentry *
+vxfs_lookup(struct inode *dip, struct dentry *dp, unsigned int flags)
+{
+ struct inode *ip = NULL;
+ ino_t ino;
+
+ if (dp->d_name.len > VXFS_NAMELEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ ino = vxfs_inode_by_name(dip, dp);
+ if (ino) {
+ ip = vxfs_iget(dip->i_sb, ino);
+ if (IS_ERR(ip))
+ return ERR_CAST(ip);
+ }
+ d_add(dp, ip);
+ return NULL;
+}
+
+/**
+ * vxfs_readdir - read a directory
+ * @fp: the directory to read
+ * @retp: return buffer
+ * @filler: filldir callback
+ *
+ * Description:
+ * vxfs_readdir fills @retp with directory entries from @fp
+ * using the VFS supplied callback @filler.
+ *
+ * Returns:
+ * Zero.
+ */
+static int
+vxfs_readdir(struct file *fp, struct dir_context *ctx)
+{
+ struct inode *ip = file_inode(fp);
+ struct super_block *sbp = ip->i_sb;
+ u_long bsize = sbp->s_blocksize;
+ u_long page, npages, block, pblocks, nblocks, offset;
+ loff_t pos;
+
+ if (ctx->pos == 0) {
+ if (!dir_emit_dot(fp, ctx))
+ return 0;
+ ctx->pos = 1;
+ }
+ if (ctx->pos == 1) {
+ if (!dir_emit(ctx, "..", 2, VXFS_INO(ip)->vii_dotdot, DT_DIR))
+ return 0;
+ ctx->pos = 2;
+ }
+ pos = ctx->pos - 2;
+
+ if (pos > VXFS_DIRROUND(ip->i_size))
+ return 0;
+
+ npages = dir_pages(ip);
+ nblocks = dir_blocks(ip);
+ pblocks = VXFS_BLOCK_PER_PAGE(sbp);
+
+ page = pos >> PAGE_CACHE_SHIFT;
+ offset = pos & ~PAGE_CACHE_MASK;
+ block = (u_long)(pos >> sbp->s_blocksize_bits) % pblocks;
+
+ for (; page < npages; page++, block = 0) {
+ char *kaddr;
+ struct page *pp;
+
+ pp = vxfs_get_page(ip->i_mapping, page);
+ if (IS_ERR(pp))
+ continue;
+ kaddr = (char *)page_address(pp);
+
+ for (; block <= nblocks && block <= pblocks; block++) {
+ char *baddr, *limit;
+ struct vxfs_dirblk *dbp;
+ struct vxfs_direct *de;
+
+ baddr = kaddr + (block * bsize);
+ limit = baddr + bsize - VXFS_DIRLEN(1);
+
+ dbp = (struct vxfs_dirblk *)baddr;
+ de = (struct vxfs_direct *)
+ (offset ?
+ (kaddr + offset) :
+ (baddr + VXFS_DIRBLKOV(dbp)));
+
+ for (; (char *)de <= limit; de = vxfs_next_entry(de)) {
+ if (!de->d_reclen)
+ break;
+ if (!de->d_ino)
+ continue;
+
+ offset = (char *)de - kaddr;
+ ctx->pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
+ if (!dir_emit(ctx, de->d_name, de->d_namelen,
+ de->d_ino, DT_UNKNOWN)) {
+ vxfs_put_page(pp);
+ return 0;
+ }
+ }
+ offset = 0;
+ }
+ vxfs_put_page(pp);
+ offset = 0;
+ }
+ ctx->pos = ((page << PAGE_CACHE_SHIFT) | offset) + 2;
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff