[PATCH] FUSE - read-only operations
This patch adds the read-only filesystem operations of FUSE.
This contains the following files:
o dir.c
- directory, symlink and file-inode operations
The following operations are added:
o lookup
o getattr
o readlink
o follow_link
o directory open
o readdir
o directory release
o permission
o dentry revalidate
o statfs
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
index 21021c35..c34e268 100644
--- a/fs/fuse/Makefile
+++ b/fs/fuse/Makefile
@@ -4,4 +4,4 @@
obj-$(CONFIG_FUSE_FS) += fuse.o
-fuse-objs := dev.o inode.o
+fuse-objs := dev.o dir.o inode.o
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 9aaf10a..e8f3170 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -691,6 +691,13 @@
return NULL;
}
+/* fget() needs to be done in this context */
+static void process_getdir(struct fuse_req *req)
+{
+ struct fuse_getdir_out_i *arg = req->out.args[0].value;
+ arg->file = fget(arg->fd);
+}
+
static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
unsigned nbytes)
{
@@ -770,6 +777,8 @@
if (!err) {
if (req->interrupted)
err = -ENOENT;
+ else if (req->in.h.opcode == FUSE_GETDIR && !oh.error)
+ process_getdir(req);
} else if (!req->interrupted)
req->out.h.error = -EIO;
request_end(fc, req);
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
new file mode 100644
index 0000000..a89730e
--- /dev/null
+++ b/fs/fuse/dir.c
@@ -0,0 +1,413 @@
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+*/
+
+#include "fuse_i.h"
+
+#include <linux/pagemap.h>
+#include <linux/file.h>
+#include <linux/gfp.h>
+#include <linux/sched.h>
+#include <linux/namei.h>
+
+static inline unsigned long time_to_jiffies(unsigned long sec,
+ unsigned long nsec)
+{
+ struct timespec ts = {sec, nsec};
+ return jiffies + timespec_to_jiffies(&ts);
+}
+
+static void fuse_lookup_init(struct fuse_req *req, struct inode *dir,
+ struct dentry *entry,
+ struct fuse_entry_out *outarg)
+{
+ req->in.h.opcode = FUSE_LOOKUP;
+ req->in.h.nodeid = get_node_id(dir);
+ req->inode = dir;
+ req->in.numargs = 1;
+ req->in.args[0].size = entry->d_name.len + 1;
+ req->in.args[0].value = entry->d_name.name;
+ req->out.numargs = 1;
+ req->out.args[0].size = sizeof(struct fuse_entry_out);
+ req->out.args[0].value = outarg;
+}
+
+static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
+{
+ if (!entry->d_inode || is_bad_inode(entry->d_inode))
+ return 0;
+ else if (time_after(jiffies, entry->d_time)) {
+ int err;
+ int version;
+ struct fuse_entry_out outarg;
+ struct inode *inode = entry->d_inode;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_req *req = fuse_get_request_nonint(fc);
+ if (!req)
+ return 0;
+
+ fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg);
+ request_send_nonint(fc, req);
+ version = req->out.h.unique;
+ err = req->out.h.error;
+ fuse_put_request(fc, req);
+ if (err || outarg.nodeid != get_node_id(inode) ||
+ (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
+ return 0;
+
+ fuse_change_attributes(inode, &outarg.attr);
+ inode->i_version = version;
+ entry->d_time = time_to_jiffies(outarg.entry_valid,
+ outarg.entry_valid_nsec);
+ fi->i_time = time_to_jiffies(outarg.attr_valid,
+ outarg.attr_valid_nsec);
+ }
+ return 1;
+}
+
+static struct dentry_operations fuse_dentry_operations = {
+ .d_revalidate = fuse_dentry_revalidate,
+};
+
+static int fuse_lookup_iget(struct inode *dir, struct dentry *entry,
+ struct inode **inodep)
+{
+ int err;
+ int version;
+ struct fuse_entry_out outarg;
+ struct inode *inode = NULL;
+ struct fuse_conn *fc = get_fuse_conn(dir);
+ struct fuse_req *req;
+
+ if (entry->d_name.len > FUSE_NAME_MAX)
+ return -ENAMETOOLONG;
+
+ req = fuse_get_request(fc);
+ if (!req)
+ return -ERESTARTNOINTR;
+
+ fuse_lookup_init(req, dir, entry, &outarg);
+ request_send(fc, req);
+ version = req->out.h.unique;
+ err = req->out.h.error;
+ if (!err) {
+ inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
+ &outarg.attr, version);
+ if (!inode) {
+ fuse_send_forget(fc, req, outarg.nodeid, version);
+ return -ENOMEM;
+ }
+ }
+ fuse_put_request(fc, req);
+ if (err && err != -ENOENT)
+ return err;
+
+ if (inode) {
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ entry->d_time = time_to_jiffies(outarg.entry_valid,
+ outarg.entry_valid_nsec);
+ fi->i_time = time_to_jiffies(outarg.attr_valid,
+ outarg.attr_valid_nsec);
+ }
+
+ entry->d_op = &fuse_dentry_operations;
+ *inodep = inode;
+ return 0;
+}
+
+int fuse_do_getattr(struct inode *inode)
+{
+ int err;
+ struct fuse_attr_out arg;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_req *req = fuse_get_request(fc);
+ if (!req)
+ return -ERESTARTNOINTR;
+
+ req->in.h.opcode = FUSE_GETATTR;
+ req->in.h.nodeid = get_node_id(inode);
+ req->inode = inode;
+ req->out.numargs = 1;
+ req->out.args[0].size = sizeof(arg);
+ req->out.args[0].value = &arg;
+ request_send(fc, req);
+ err = req->out.h.error;
+ fuse_put_request(fc, req);
+ if (!err) {
+ if ((inode->i_mode ^ arg.attr.mode) & S_IFMT) {
+ make_bad_inode(inode);
+ err = -EIO;
+ } else {
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ fuse_change_attributes(inode, &arg.attr);
+ fi->i_time = time_to_jiffies(arg.attr_valid,
+ arg.attr_valid_nsec);
+ }
+ }
+ return err;
+}
+
+static int fuse_revalidate(struct dentry *entry)
+{
+ struct inode *inode = entry->d_inode;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ if (get_node_id(inode) == FUSE_ROOT_ID) {
+ if (current->fsuid != fc->user_id)
+ return -EACCES;
+ } else if (time_before_eq(jiffies, fi->i_time))
+ return 0;
+
+ return fuse_do_getattr(inode);
+}
+
+static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ if (current->fsuid != fc->user_id)
+ return -EACCES;
+ else {
+ int mode = inode->i_mode;
+ if ((mask & MAY_WRITE) && IS_RDONLY(inode) &&
+ (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
+ return -EROFS;
+ if ((mask & MAY_EXEC) && !S_ISDIR(mode) && !(mode & S_IXUGO))
+ return -EACCES;
+ return 0;
+ }
+}
+
+static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
+ void *dstbuf, filldir_t filldir)
+{
+ while (nbytes >= FUSE_NAME_OFFSET) {
+ struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
+ size_t reclen = FUSE_DIRENT_SIZE(dirent);
+ int over;
+ if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
+ return -EIO;
+ if (reclen > nbytes)
+ break;
+
+ over = filldir(dstbuf, dirent->name, dirent->namelen,
+ file->f_pos, dirent->ino, dirent->type);
+ if (over)
+ break;
+
+ buf += reclen;
+ nbytes -= reclen;
+ file->f_pos = dirent->off;
+ }
+
+ return 0;
+}
+
+static int fuse_checkdir(struct file *cfile, struct file *file)
+{
+ struct inode *inode;
+ if (!cfile)
+ return -EIO;
+ inode = cfile->f_dentry->d_inode;
+ if (!S_ISREG(inode->i_mode)) {
+ fput(cfile);
+ return -EIO;
+ }
+
+ file->private_data = cfile;
+ return 0;
+}
+
+static int fuse_getdir(struct file *file)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_req *req = fuse_get_request(fc);
+ struct fuse_getdir_out_i outarg;
+ int err;
+
+ if (!req)
+ return -ERESTARTNOINTR;
+
+ req->in.h.opcode = FUSE_GETDIR;
+ req->in.h.nodeid = get_node_id(inode);
+ req->inode = inode;
+ req->out.numargs = 1;
+ req->out.args[0].size = sizeof(struct fuse_getdir_out);
+ req->out.args[0].value = &outarg;
+ request_send(fc, req);
+ err = req->out.h.error;
+ fuse_put_request(fc, req);
+ if (!err)
+ err = fuse_checkdir(outarg.file, file);
+ return err;
+}
+
+static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
+{
+ struct file *cfile = file->private_data;
+ char *buf;
+ int ret;
+
+ if (!cfile) {
+ ret = fuse_getdir(file);
+ if (ret)
+ return ret;
+
+ cfile = file->private_data;
+ }
+
+ buf = (char *) __get_free_page(GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ ret = kernel_read(cfile, file->f_pos, buf, PAGE_SIZE);
+ if (ret > 0)
+ ret = parse_dirfile(buf, ret, file, dstbuf, filldir);
+
+ free_page((unsigned long) buf);
+ return ret;
+}
+
+static char *read_link(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_req *req = fuse_get_request(fc);
+ char *link;
+
+ if (!req)
+ return ERR_PTR(-ERESTARTNOINTR);
+
+ link = (char *) __get_free_page(GFP_KERNEL);
+ if (!link) {
+ link = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+ req->in.h.opcode = FUSE_READLINK;
+ req->in.h.nodeid = get_node_id(inode);
+ req->inode = inode;
+ req->out.argvar = 1;
+ req->out.numargs = 1;
+ req->out.args[0].size = PAGE_SIZE - 1;
+ req->out.args[0].value = link;
+ request_send(fc, req);
+ if (req->out.h.error) {
+ free_page((unsigned long) link);
+ link = ERR_PTR(req->out.h.error);
+ } else
+ link[req->out.args[0].size] = '\0';
+ out:
+ fuse_put_request(fc, req);
+ return link;
+}
+
+static void free_link(char *link)
+{
+ if (!IS_ERR(link))
+ free_page((unsigned long) link);
+}
+
+static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ nd_set_link(nd, read_link(dentry));
+ return NULL;
+}
+
+static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
+{
+ free_link(nd_get_link(nd));
+}
+
+static int fuse_dir_open(struct inode *inode, struct file *file)
+{
+ file->private_data = NULL;
+ return 0;
+}
+
+static int fuse_dir_release(struct inode *inode, struct file *file)
+{
+ struct file *cfile = file->private_data;
+
+ if (cfile)
+ fput(cfile);
+
+ return 0;
+}
+
+static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
+ struct kstat *stat)
+{
+ struct inode *inode = entry->d_inode;
+ int err = fuse_revalidate(entry);
+ if (!err)
+ generic_fillattr(inode, stat);
+
+ return err;
+}
+
+static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
+ struct nameidata *nd)
+{
+ struct inode *inode;
+ int err = fuse_lookup_iget(dir, entry, &inode);
+ if (err)
+ return ERR_PTR(err);
+ if (inode && S_ISDIR(inode->i_mode)) {
+ /* Don't allow creating an alias to a directory */
+ struct dentry *alias = d_find_alias(inode);
+ if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
+ dput(alias);
+ iput(inode);
+ return ERR_PTR(-EIO);
+ }
+ }
+ return d_splice_alias(inode, entry);
+}
+
+static struct inode_operations fuse_dir_inode_operations = {
+ .lookup = fuse_lookup,
+ .permission = fuse_permission,
+ .getattr = fuse_getattr,
+};
+
+static struct file_operations fuse_dir_operations = {
+ .read = generic_read_dir,
+ .readdir = fuse_readdir,
+ .open = fuse_dir_open,
+ .release = fuse_dir_release,
+};
+
+static struct inode_operations fuse_common_inode_operations = {
+ .permission = fuse_permission,
+ .getattr = fuse_getattr,
+};
+
+static struct inode_operations fuse_symlink_inode_operations = {
+ .follow_link = fuse_follow_link,
+ .put_link = fuse_put_link,
+ .readlink = generic_readlink,
+ .getattr = fuse_getattr,
+};
+
+void fuse_init_common(struct inode *inode)
+{
+ inode->i_op = &fuse_common_inode_operations;
+}
+
+void fuse_init_dir(struct inode *inode)
+{
+ inode->i_op = &fuse_dir_inode_operations;
+ inode->i_fop = &fuse_dir_operations;
+}
+
+void fuse_init_symlink(struct inode *inode)
+{
+ inode->i_op = &fuse_symlink_inode_operations;
+}
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 50ad6a0..8d91e14 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -30,6 +30,9 @@
* and kernel */
u64 nodeid;
+ /** The request used for sending the FORGET message */
+ struct fuse_req *forget_req;
+
/** Time in jiffies until the file attributes are valid */
unsigned long i_time;
};
@@ -129,6 +132,7 @@
/** Data for asynchronous requests */
union {
+ struct fuse_forget_in forget_in;
struct fuse_init_in_out init_in_out;
} misc;
@@ -197,6 +201,11 @@
struct backing_dev_info bdi;
};
+struct fuse_getdir_out_i {
+ int fd;
+ void *file; /* Used by kernel only */
+};
+
static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
{
return (struct fuse_conn **) &sb->s_fs_info;
@@ -240,6 +249,38 @@
extern spinlock_t fuse_lock;
/**
+ * Get a filled in inode
+ */
+struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
+ int generation, struct fuse_attr *attr, int version);
+
+/**
+ * Send FORGET command
+ */
+void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
+ unsigned long nodeid, int version);
+
+/**
+ * Initialise inode operations on regular files and special files
+ */
+void fuse_init_common(struct inode *inode);
+
+/**
+ * Initialise inode and file operations on a directory
+ */
+void fuse_init_dir(struct inode *inode);
+
+/**
+ * Initialise inode operations on a symlink
+ */
+void fuse_init_symlink(struct inode *inode);
+
+/**
+ * Change attributes of an inode
+ */
+void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
+
+/**
* Check if the connection can be released, and if yes, then free the
* connection structure
*/
@@ -307,6 +348,16 @@
void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
/**
+ * Get the attributes of a file
+ */
+int fuse_do_getattr(struct inode *inode);
+
+/**
+ * Invalidate inode attributes
+ */
+void fuse_invalidate_attr(struct inode *inode);
+
+/**
* Send the INIT message
*/
void fuse_send_init(struct fuse_conn *fc);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 33fad33..41498a1 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -51,12 +51,20 @@
fi = get_fuse_inode(inode);
fi->i_time = jiffies - 1;
fi->nodeid = 0;
+ fi->forget_req = fuse_request_alloc();
+ if (!fi->forget_req) {
+ kmem_cache_free(fuse_inode_cachep, inode);
+ return NULL;
+ }
return inode;
}
static void fuse_destroy_inode(struct inode *inode)
{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ if (fi->forget_req)
+ fuse_request_free(fi->forget_req);
kmem_cache_free(fuse_inode_cachep, inode);
}
@@ -65,8 +73,27 @@
/* No op */
}
+void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
+ unsigned long nodeid, int version)
+{
+ struct fuse_forget_in *inarg = &req->misc.forget_in;
+ inarg->version = version;
+ req->in.h.opcode = FUSE_FORGET;
+ req->in.h.nodeid = nodeid;
+ req->in.numargs = 1;
+ req->in.args[0].size = sizeof(struct fuse_forget_in);
+ req->in.args[0].value = inarg;
+ request_send_noreply(fc, req);
+}
+
static void fuse_clear_inode(struct inode *inode)
{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ if (fc) {
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ fuse_send_forget(fc, fi->forget_req, fi->nodeid, inode->i_version);
+ fi->forget_req = NULL;
+ }
}
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
@@ -94,6 +121,22 @@
{
inode->i_mode = attr->mode & S_IFMT;
i_size_write(inode, attr->size);
+ if (S_ISREG(inode->i_mode)) {
+ fuse_init_common(inode);
+ } else if (S_ISDIR(inode->i_mode))
+ fuse_init_dir(inode);
+ else if (S_ISLNK(inode->i_mode))
+ fuse_init_symlink(inode);
+ else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+ S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
+ fuse_init_common(inode);
+ init_special_inode(inode, inode->i_mode,
+ new_decode_dev(attr->rdev));
+ } else {
+ /* Don't let user create weird files */
+ inode->i_mode = S_IFREG;
+ fuse_init_common(inode);
+ }
}
static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
@@ -158,6 +201,43 @@
spin_unlock(&fuse_lock);
}
+static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
+{
+ stbuf->f_type = FUSE_SUPER_MAGIC;
+ stbuf->f_bsize = attr->bsize;
+ stbuf->f_blocks = attr->blocks;
+ stbuf->f_bfree = attr->bfree;
+ stbuf->f_bavail = attr->bavail;
+ stbuf->f_files = attr->files;
+ stbuf->f_ffree = attr->ffree;
+ stbuf->f_namelen = attr->namelen;
+ /* fsid is left zero */
+}
+
+static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+ struct fuse_req *req;
+ struct fuse_statfs_out outarg;
+ int err;
+
+ req = fuse_get_request(fc);
+ if (!req)
+ return -ERESTARTSYS;
+
+ req->in.numargs = 0;
+ req->in.h.opcode = FUSE_STATFS;
+ req->out.numargs = 1;
+ req->out.args[0].size = sizeof(outarg);
+ req->out.args[0].value = &outarg;
+ request_send(fc, req);
+ err = req->out.h.error;
+ if (!err)
+ convert_fuse_statfs(buf, &outarg.st);
+ fuse_put_request(fc, req);
+ return err;
+}
+
enum {
OPT_FD,
OPT_ROOTMODE,
@@ -318,6 +398,7 @@
.read_inode = fuse_read_inode,
.clear_inode = fuse_clear_inode,
.put_super = fuse_put_super,
+ .statfs = fuse_statfs,
.show_options = fuse_show_options,
};
diff --git a/include/linux/fuse.h b/include/linux/fuse.h
index a1aebd7..21b9ba1 100644
--- a/include/linux/fuse.h
+++ b/include/linux/fuse.h
@@ -42,13 +42,61 @@
__u32 rdev;
};
+struct fuse_kstatfs {
+ __u64 blocks;
+ __u64 bfree;
+ __u64 bavail;
+ __u64 files;
+ __u64 ffree;
+ __u32 bsize;
+ __u32 namelen;
+};
+
enum fuse_opcode {
+ FUSE_LOOKUP = 1,
+ FUSE_FORGET = 2, /* no reply */
+ FUSE_GETATTR = 3,
+ FUSE_READLINK = 5,
+ FUSE_GETDIR = 7,
+ FUSE_STATFS = 17,
FUSE_INIT = 26
};
/* Conservative buffer size for the client */
#define FUSE_MAX_IN 8192
+#define FUSE_NAME_MAX 1024
+
+struct fuse_entry_out {
+ __u64 nodeid; /* Inode ID */
+ __u64 generation; /* Inode generation: nodeid:gen must
+ be unique for the fs's lifetime */
+ __u64 entry_valid; /* Cache timeout for the name */
+ __u64 attr_valid; /* Cache timeout for the attributes */
+ __u32 entry_valid_nsec;
+ __u32 attr_valid_nsec;
+ struct fuse_attr attr;
+};
+
+struct fuse_forget_in {
+ __u64 version;
+};
+
+struct fuse_attr_out {
+ __u64 attr_valid; /* Cache timeout for the attributes */
+ __u32 attr_valid_nsec;
+ __u32 dummy;
+ struct fuse_attr attr;
+};
+
+struct fuse_getdir_out {
+ __u32 fd;
+};
+
+struct fuse_statfs_out {
+ struct fuse_kstatfs st;
+};
+
struct fuse_init_in_out {
__u32 major;
__u32 minor;
@@ -70,3 +118,15 @@
__u64 unique;
};
+struct fuse_dirent {
+ __u64 ino;
+ __u64 off;
+ __u32 namelen;
+ __u32 type;
+ char name[0];
+};
+
+#define FUSE_NAME_OFFSET ((unsigned) ((struct fuse_dirent *) 0)->name)
+#define FUSE_DIRENT_ALIGN(x) (((x) + sizeof(__u64) - 1) & ~(sizeof(__u64) - 1))
+#define FUSE_DIRENT_SIZE(d) \
+ FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)