/* * 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 = source_de->d_inode; 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(de->d_inode); 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 (de->d_inode) clear_nlink(de->d_inode); /* 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 (new_dentry->d_inode) { 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(new_dentry->d_inode, 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 = de->d_inode; if (!inode || is_root_inode(inode)) goto out; if (is_bad_inode(inode)) goto bad; cii = ITOC(de->d_inode); 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 (!dentry->d_inode) return 0; flags = (ITOC(dentry->d_inode)->c_flags) & C_PURGE; if (is_bad_inode(dentry->d_inode) || 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, };