--- /dev/null
+
+/*
+ * Directory operations for Coda filesystem
+ * Original version: (C) 1996 P. Braam and M. Callahan
+ * Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University
+ *
+ * Carnegie Mellon encourages users to contribute improvements to
+ * the Coda project. Contact Peter Braam (coda@cs.cmu.edu).
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/namei.h>
+#include <linux/uaccess.h>
+
+#include <linux/coda.h>
+#include <linux/coda_psdev.h>
+#include "coda_linux.h"
+#include "coda_cache.h"
+
+#include "coda_int.h"
+
+/* same as fs/bad_inode.c */
+static int coda_return_EIO(void)
+{
+ return -EIO;
+}
+#define CODA_EIO_ERROR ((void *) (coda_return_EIO))
+
+/* inode operations for directories */
+/* access routines: lookup, readlink, permission */
+static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, unsigned int flags)
+{
+ struct super_block *sb = dir->i_sb;
+ const char *name = entry->d_name.name;
+ size_t length = entry->d_name.len;
+ struct inode *inode;
+ int type = 0;
+
+ if (length > CODA_MAXNAMLEN) {
+ pr_err("name too long: lookup, %s (%*s)\n",
+ coda_i2s(dir), (int)length, name);
+ return ERR_PTR(-ENAMETOOLONG);
+ }
+
+ /* control object, create inode on the fly */
+ if (is_root_inode(dir) && coda_iscontrol(name, length)) {
+ inode = coda_cnode_makectl(sb);
+ type = CODA_NOCACHE;
+ } else {
+ struct CodaFid fid = { { 0, } };
+ int error = venus_lookup(sb, coda_i2f(dir), name, length,
+ &type, &fid);
+ inode = !error ? coda_cnode_make(&fid, sb) : ERR_PTR(error);
+ }
+
+ if (!IS_ERR(inode) && (type & CODA_NOCACHE))
+ coda_flag_inode(inode, C_VATTR | C_PURGE);
+
+ if (inode == ERR_PTR(-ENOENT))
+ inode = NULL;
+
+ return d_splice_alias(inode, entry);
+}
+
+
+int coda_permission(struct inode *inode, int mask)
+{
+ int error;
+
+ if (mask & MAY_NOT_BLOCK)
+ return -ECHILD;
+
+ mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
+
+ if (!mask)
+ return 0;
+
+ if ((mask & MAY_EXEC) && !execute_ok(inode))
+ return -EACCES;
+
+ if (coda_cache_check(inode, mask))
+ return 0;
+
+ error = venus_access(inode->i_sb, coda_i2f(inode), mask);
+
+ if (!error)
+ coda_cache_enter(inode, mask);
+
+ return error;
+}
+
+
+static inline void coda_dir_update_mtime(struct inode *dir)
+{
+#ifdef REQUERY_VENUS_FOR_MTIME
+ /* invalidate the directory cnode's attributes so we refetch the
+ * attributes from venus next time the inode is referenced */
+ coda_flag_inode(dir, C_VATTR);
+#else
+ /* optimistically we can also act as if our nose bleeds. The
+ * granularity of the mtime is coarse anyways so we might actually be
+ * right most of the time. Note: we only do this for directories. */
+ dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+#endif
+}
+
+/* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a
+ * trick to fool GNU find's optimizations. If we can't be sure of the link
+ * (because of volume mount points) we set i_nlink to 1 which forces find
+ * to consider every child as a possible directory. We should also never
+ * see an increment or decrement for deleted directories where i_nlink == 0 */
+static inline void coda_dir_inc_nlink(struct inode *dir)
+{
+ if (dir->i_nlink >= 2)
+ inc_nlink(dir);
+}
+
+static inline void coda_dir_drop_nlink(struct inode *dir)
+{
+ if (dir->i_nlink > 2)
+ drop_nlink(dir);
+}
+
+/* creation routines: create, mknod, mkdir, link, symlink */
+static int coda_create(struct inode *dir, struct dentry *de, umode_t mode, bool excl)
+{
+ int error;
+ const char *name=de->d_name.name;
+ int length=de->d_name.len;
+ struct inode *inode;
+ struct CodaFid newfid;
+ struct coda_vattr attrs;
+
+ if (is_root_inode(dir) && coda_iscontrol(name, length))
+ return -EPERM;
+
+ error = venus_create(dir->i_sb, coda_i2f(dir), name, length,
+ 0, mode, &newfid, &attrs);
+ if (error)
+ goto err_out;
+
+ inode = coda_iget(dir->i_sb, &newfid, &attrs);
+ if (IS_ERR(inode)) {
+ error = PTR_ERR(inode);
+ goto err_out;
+ }
+
+ /* invalidate the directory cnode's attributes */
+ coda_dir_update_mtime(dir);
+ d_instantiate(de, inode);
+ return 0;
+err_out:
+ d_drop(de);
+ return error;
+}
+
+static int coda_mkdir(struct inode *dir, struct dentry *de, umode_t mode)
+{
+ struct inode *inode;
+ struct coda_vattr attrs;
+ const char *name = de->d_name.name;
+ int len = de->d_name.len;
+ int error;
+ struct CodaFid newfid;
+
+ if (is_root_inode(dir) && coda_iscontrol(name, len))
+ return -EPERM;
+
+ attrs.va_mode = mode;
+ error = venus_mkdir(dir->i_sb, coda_i2f(dir),
+ name, len, &newfid, &attrs);
+ if (error)
+ goto err_out;
+
+ inode = coda_iget(dir->i_sb, &newfid, &attrs);
+ if (IS_ERR(inode)) {
+ error = PTR_ERR(inode);
+ goto err_out;
+ }
+
+ /* invalidate the directory cnode's attributes */
+ coda_dir_inc_nlink(dir);
+ coda_dir_update_mtime(dir);
+ d_instantiate(de, inode);
+ return 0;
+err_out:
+ d_drop(de);
+ return error;
+}
+
+/* try to make de an entry in dir_inodde linked to source_de */
+static int coda_link(struct dentry *source_de, struct inode *dir_inode,
+ struct dentry *de)
+{
+ struct inode *inode = d_inode(source_de);
+ const char * name = de->d_name.name;
+ int len = de->d_name.len;
+ int error;
+
+ if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
+ return -EPERM;
+
+ error = venus_link(dir_inode->i_sb, coda_i2f(inode),
+ coda_i2f(dir_inode), (const char *)name, len);
+ if (error) {
+ d_drop(de);
+ return error;
+ }
+
+ coda_dir_update_mtime(dir_inode);
+ ihold(inode);
+ d_instantiate(de, inode);
+ inc_nlink(inode);
+ return 0;
+}
+
+
+static int coda_symlink(struct inode *dir_inode, struct dentry *de,
+ const char *symname)
+{
+ const char *name = de->d_name.name;
+ int len = de->d_name.len;
+ int symlen;
+ int error;
+
+ if (is_root_inode(dir_inode) && coda_iscontrol(name, len))
+ return -EPERM;
+
+ symlen = strlen(symname);
+ if (symlen > CODA_MAXPATHLEN)
+ return -ENAMETOOLONG;
+
+ /*
+ * This entry is now negative. Since we do not create
+ * an inode for the entry we have to drop it.
+ */
+ d_drop(de);
+ error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len,
+ symname, symlen);
+
+ /* mtime is no good anymore */
+ if (!error)
+ coda_dir_update_mtime(dir_inode);
+
+ return error;
+}
+
+/* destruction routines: unlink, rmdir */
+static int coda_unlink(struct inode *dir, struct dentry *de)
+{
+ int error;
+ const char *name = de->d_name.name;
+ int len = de->d_name.len;
+
+ error = venus_remove(dir->i_sb, coda_i2f(dir), name, len);
+ if (error)
+ return error;
+
+ coda_dir_update_mtime(dir);
+ drop_nlink(d_inode(de));
+ return 0;
+}
+
+static int coda_rmdir(struct inode *dir, struct dentry *de)
+{
+ const char *name = de->d_name.name;
+ int len = de->d_name.len;
+ int error;
+
+ error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len);
+ if (!error) {
+ /* VFS may delete the child */
+ if (d_really_is_positive(de))
+ clear_nlink(d_inode(de));
+
+ /* fix the link count of the parent */
+ coda_dir_drop_nlink(dir);
+ coda_dir_update_mtime(dir);
+ }
+ return error;
+}
+
+/* rename */
+static int coda_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
+{
+ const char *old_name = old_dentry->d_name.name;
+ const char *new_name = new_dentry->d_name.name;
+ int old_length = old_dentry->d_name.len;
+ int new_length = new_dentry->d_name.len;
+ int error;
+
+ error = venus_rename(old_dir->i_sb, coda_i2f(old_dir),
+ coda_i2f(new_dir), old_length, new_length,
+ (const char *) old_name, (const char *)new_name);
+ if (!error) {
+ if (d_really_is_positive(new_dentry)) {
+ if (d_is_dir(new_dentry)) {
+ coda_dir_drop_nlink(old_dir);
+ coda_dir_inc_nlink(new_dir);
+ }
+ coda_dir_update_mtime(old_dir);
+ coda_dir_update_mtime(new_dir);
+ coda_flag_inode(d_inode(new_dentry), C_VATTR);
+ } else {
+ coda_flag_inode(old_dir, C_VATTR);
+ coda_flag_inode(new_dir, C_VATTR);
+ }
+ }
+ return error;
+}
+
+static inline unsigned int CDT2DT(unsigned char cdt)
+{
+ unsigned int dt;
+
+ switch(cdt) {
+ case CDT_UNKNOWN: dt = DT_UNKNOWN; break;
+ case CDT_FIFO: dt = DT_FIFO; break;
+ case CDT_CHR: dt = DT_CHR; break;
+ case CDT_DIR: dt = DT_DIR; break;
+ case CDT_BLK: dt = DT_BLK; break;
+ case CDT_REG: dt = DT_REG; break;
+ case CDT_LNK: dt = DT_LNK; break;
+ case CDT_SOCK: dt = DT_SOCK; break;
+ case CDT_WHT: dt = DT_WHT; break;
+ default: dt = DT_UNKNOWN; break;
+ }
+ return dt;
+}
+
+/* support routines */
+static int coda_venus_readdir(struct file *coda_file, struct dir_context *ctx)
+{
+ struct coda_file_info *cfi;
+ struct coda_inode_info *cii;
+ struct file *host_file;
+ struct venus_dirent *vdir;
+ unsigned long vdir_size = offsetof(struct venus_dirent, d_name);
+ unsigned int type;
+ struct qstr name;
+ ino_t ino;
+ int ret;
+
+ cfi = CODA_FTOC(coda_file);
+ BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
+ host_file = cfi->cfi_container;
+
+ cii = ITOC(file_inode(coda_file));
+
+ vdir = kmalloc(sizeof(*vdir), GFP_KERNEL);
+ if (!vdir) return -ENOMEM;
+
+ if (!dir_emit_dots(coda_file, ctx))
+ goto out;
+
+ while (1) {
+ /* read entries from the directory file */
+ ret = kernel_read(host_file, ctx->pos - 2, (char *)vdir,
+ sizeof(*vdir));
+ if (ret < 0) {
+ pr_err("%s: read dir %s failed %d\n",
+ __func__, coda_f2s(&cii->c_fid), ret);
+ break;
+ }
+ if (ret == 0) break; /* end of directory file reached */
+
+ /* catch truncated reads */
+ if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) {
+ pr_err("%s: short read on %s\n",
+ __func__, coda_f2s(&cii->c_fid));
+ ret = -EBADF;
+ break;
+ }
+ /* validate whether the directory file actually makes sense */
+ if (vdir->d_reclen < vdir_size + vdir->d_namlen) {
+ pr_err("%s: invalid dir %s\n",
+ __func__, coda_f2s(&cii->c_fid));
+ ret = -EBADF;
+ break;
+ }
+
+ name.len = vdir->d_namlen;
+ name.name = vdir->d_name;
+
+ /* Make sure we skip '.' and '..', we already got those */
+ if (name.name[0] == '.' && (name.len == 1 ||
+ (name.name[1] == '.' && name.len == 2)))
+ vdir->d_fileno = name.len = 0;
+
+ /* skip null entries */
+ if (vdir->d_fileno && name.len) {
+ ino = vdir->d_fileno;
+ type = CDT2DT(vdir->d_type);
+ if (!dir_emit(ctx, name.name, name.len, ino, type))
+ break;
+ }
+ /* we'll always have progress because d_reclen is unsigned and
+ * we've already established it is non-zero. */
+ ctx->pos += vdir->d_reclen;
+ }
+out:
+ kfree(vdir);
+ return 0;
+}
+
+/* file operations for directories */
+static int coda_readdir(struct file *coda_file, struct dir_context *ctx)
+{
+ struct coda_file_info *cfi;
+ struct file *host_file;
+ int ret;
+
+ cfi = CODA_FTOC(coda_file);
+ BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
+ host_file = cfi->cfi_container;
+
+ if (host_file->f_op->iterate) {
+ struct inode *host_inode = file_inode(host_file);
+
+ mutex_lock(&host_inode->i_mutex);
+ ret = -ENOENT;
+ if (!IS_DEADDIR(host_inode)) {
+ ret = host_file->f_op->iterate(host_file, ctx);
+ file_accessed(host_file);
+ }
+ mutex_unlock(&host_inode->i_mutex);
+ return ret;
+ }
+ /* Venus: we must read Venus dirents from a file */
+ return coda_venus_readdir(coda_file, ctx);
+}
+
+/* called when a cache lookup succeeds */
+static int coda_dentry_revalidate(struct dentry *de, unsigned int flags)
+{
+ struct inode *inode;
+ struct coda_inode_info *cii;
+
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ inode = d_inode(de);
+ if (!inode || is_root_inode(inode))
+ goto out;
+ if (is_bad_inode(inode))
+ goto bad;
+
+ cii = ITOC(d_inode(de));
+ if (!(cii->c_flags & (C_PURGE | C_FLUSH)))
+ goto out;
+
+ shrink_dcache_parent(de);
+
+ /* propagate for a flush */
+ if (cii->c_flags & C_FLUSH)
+ coda_flag_inode_children(inode, C_FLUSH);
+
+ if (d_count(de) > 1)
+ /* pretend it's valid, but don't change the flags */
+ goto out;
+
+ /* clear the flags. */
+ spin_lock(&cii->c_lock);
+ cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
+ spin_unlock(&cii->c_lock);
+bad:
+ return 0;
+out:
+ return 1;
+}
+
+/*
+ * This is the callback from dput() when d_count is going to 0.
+ * We use this to unhash dentries with bad inodes.
+ */
+static int coda_dentry_delete(const struct dentry * dentry)
+{
+ int flags;
+
+ if (d_really_is_negative(dentry))
+ return 0;
+
+ flags = (ITOC(d_inode(dentry))->c_flags) & C_PURGE;
+ if (is_bad_inode(d_inode(dentry)) || flags) {
+ return 1;
+ }
+ return 0;
+}
+
+
+
+/*
+ * This is called when we want to check if the inode has
+ * changed on the server. Coda makes this easy since the
+ * cache manager Venus issues a downcall to the kernel when this
+ * happens
+ */
+int coda_revalidate_inode(struct inode *inode)
+{
+ struct coda_vattr attr;
+ int error;
+ int old_mode;
+ ino_t old_ino;
+ struct coda_inode_info *cii = ITOC(inode);
+
+ if (!cii->c_flags)
+ return 0;
+
+ if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) {
+ error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr);
+ if (error)
+ return -EIO;
+
+ /* this inode may be lost if:
+ - it's ino changed
+ - type changes must be permitted for repair and
+ missing mount points.
+ */
+ old_mode = inode->i_mode;
+ old_ino = inode->i_ino;
+ coda_vattr_to_iattr(inode, &attr);
+
+ if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) {
+ pr_warn("inode %ld, fid %s changed type!\n",
+ inode->i_ino, coda_f2s(&(cii->c_fid)));
+ }
+
+ /* the following can happen when a local fid is replaced
+ with a global one, here we lose and declare the inode bad */
+ if (inode->i_ino != old_ino)
+ return -EIO;
+
+ coda_flag_inode_children(inode, C_FLUSH);
+
+ spin_lock(&cii->c_lock);
+ cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH);
+ spin_unlock(&cii->c_lock);
+ }
+ return 0;
+}
+
+const struct dentry_operations coda_dentry_operations = {
+ .d_revalidate = coda_dentry_revalidate,
+ .d_delete = coda_dentry_delete,
+};
+
+const struct inode_operations coda_dir_inode_operations = {
+ .create = coda_create,
+ .lookup = coda_lookup,
+ .link = coda_link,
+ .unlink = coda_unlink,
+ .symlink = coda_symlink,
+ .mkdir = coda_mkdir,
+ .rmdir = coda_rmdir,
+ .mknod = CODA_EIO_ERROR,
+ .rename = coda_rename,
+ .permission = coda_permission,
+ .getattr = coda_getattr,
+ .setattr = coda_setattr,
+};
+
+const struct file_operations coda_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate = coda_readdir,
+ .open = coda_open,
+ .release = coda_release,
+ .fsync = coda_fsync,
+};
Code Review / kvmfornfv.git / blobdiff