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Subject[PATCH 4/13] Filesystem in Userspace
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Date
This patch adds the read-only filesystem operations of FUSE.

The following operations are added:

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>
--- linux-2.6.10-rc2/fs/fuse/dev.c 2004-11-20 22:56:25.000000000 +0100
+++ linux-2.6.10-rc2-fuse/fs/fuse/dev.c 2004-11-20 22:56:23.000000000 +0100
@@ -268,6 +268,12 @@ static struct fuse_req *request_find(str
return req;
}

+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 inline int copy_out_one(struct fuse_out_arg *arg,
const char __user **srcp,
size_t *srclenp, int allowvar)
@@ -378,7 +384,11 @@ static ssize_t fuse_dev_write(struct fil
spin_lock(&fuse_lock);
if (err)
req->out.h.error = -EPROTO;
-
+ else {
+ /* fget() needs to be done in this context */
+ if (req->in.h.opcode == FUSE_GETDIR && !oh.error)
+ process_getdir(req);
+ }
req->finished = 1;
/* Unlocks fuse_lock: */
request_end(fc, req);
--- linux-2.6.10-rc2/fs/fuse/dir.c 2004-11-20 22:56:25.000000000 +0100
+++ linux-2.6.10-rc2-fuse/fs/fuse/dir.c 2004-11-20 22:56:25.000000000 +0100
@@ -10,8 +10,14 @@

#include <linux/pagemap.h>
#include <linux/file.h>
+#include <linux/gfp.h>
+#include <linux/sched.h>

static struct inode_operations fuse_dir_inode_operations;
+static struct inode_operations fuse_file_inode_operations;
+static struct inode_operations fuse_symlink_inode_operations;
+static struct file_operations fuse_dir_operations;
+static struct dentry_operations fuse_dentry_operations;

static void change_attributes(struct inode *inode, struct fuse_attr *attr)
{
@@ -39,8 +45,27 @@ static void fuse_init_inode(struct inode
{
inode->i_mode = attr->mode & S_IFMT;
i_size_write(inode, attr->size);
- if (S_ISDIR(inode->i_mode))
+ if (S_ISREG(inode->i_mode)) {
+ inode->i_op = &fuse_file_inode_operations;
+ }
+ else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &fuse_dir_inode_operations;
+ inode->i_fop = &fuse_dir_operations;
+ }
+ else if (S_ISLNK(inode->i_mode)) {
+ inode->i_op = &fuse_symlink_inode_operations;
+ }
+ else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+ S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
+ inode->i_op = &fuse_file_inode_operations;
+ init_special_inode(inode, inode->i_mode,
+ new_decode_dev(attr->rdev));
+ } else {
+ /* Don't let user create weird files */
+ printk("fuse_init_inode: bad file type: %o\n", inode->i_mode);
+ inode->i_mode = S_IFREG;
+ inode->i_op = &fuse_file_inode_operations;
+ }
}

static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
@@ -82,6 +107,11 @@ struct inode *fuse_iget(struct super_blo
return inode;
}

+struct inode *fuse_ilookup(struct super_block *sb, unsigned long nodeid)
+{
+ return ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
+}
+
static int fuse_send_lookup(struct fuse_conn *fc, struct fuse_req *req,
struct inode *dir, struct dentry *entry,
struct fuse_entry_out *outarg, int *version)
@@ -100,6 +130,24 @@ static int fuse_send_lookup(struct fuse_
return req->out.h.error;
}

+static int fuse_do_lookup(struct inode *dir, struct dentry *entry,
+ struct fuse_entry_out *outarg, int *version)
+{
+ struct fuse_conn *fc = INO_FC(dir);
+ struct fuse_req *req;
+ int err;
+
+ if (entry->d_name.len > FUSE_NAME_MAX)
+ return -ENAMETOOLONG;
+ req = fuse_get_request(fc);
+ if (!req)
+ return -ERESTARTSYS;
+
+ err = fuse_send_lookup(fc, req, dir, entry, outarg, version);
+ fuse_put_request(fc, req);
+ return err;
+}
+
static inline unsigned long time_to_jiffies(unsigned long sec,
unsigned long nsec)
{
@@ -147,10 +195,279 @@ static int fuse_lookup_iget(struct inode
outarg.attr_valid_nsec);
}

+ entry->d_op = &fuse_dentry_operations;
*inodep = inode;
return 0;
}

+int fuse_do_getattr(struct inode *inode)
+{
+ struct fuse_inode *fi = INO_FI(inode);
+ struct fuse_conn *fc = INO_FC(inode);
+ struct fuse_req *req = fuse_get_request(fc);
+ struct fuse_attr_out arg;
+ int err;
+
+ if (!req)
+ return -ERESTARTSYS;
+
+ req->in.h.opcode = FUSE_GETATTR;
+ req->in.h.nodeid = fi->nodeid;
+ 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;
+ if (!err) {
+ change_attributes(inode, &arg.attr);
+ fi->i_time = time_to_jiffies(arg.attr_valid,
+ arg.attr_valid_nsec);
+ }
+ fuse_put_request(fc, req);
+ return err;
+}
+
+static int fuse_revalidate(struct dentry *entry)
+{
+ struct inode *inode = entry->d_inode;
+ struct fuse_inode *fi = INO_FI(inode);
+ struct fuse_conn *fc = INO_FC(inode);
+
+ if (fi->nodeid == FUSE_ROOT_ID) {
+ if (current->fsuid != fc->uid)
+ return -EACCES;
+ } else if (!fi->i_time || 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 = INO_FC(inode);
+
+ if (current->fsuid != fc->uid)
+ return -EACCES;
+ else
+ 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 > NAME_MAX) {
+ printk("fuse_readdir: name too long\n");
+ return -EPROTO;
+ }
+ if (reclen > nbytes)
+ break;
+
+ over = filldir(dstbuf, dirent->name, dirent->namelen,
+ file->f_pos, dirent->ino, dirent->type);
+ if (over)
+ break;
+
+ buf += reclen;
+ file->f_pos += reclen;
+ nbytes -= reclen;
+ }
+
+ return 0;
+}
+
+static int fuse_checkdir(struct file *cfile, struct file *file)
+{
+ struct inode *inode;
+ if (!cfile) {
+ printk("fuse_getdir: invalid file\n");
+ return -EPROTO;
+ }
+ inode = cfile->f_dentry->d_inode;
+ if (!S_ISREG(inode->i_mode)) {
+ printk("fuse_getdir: not a regular file\n");
+ fput(cfile);
+ return -EPROTO;
+ }
+
+ 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 = INO_FC(inode);
+ struct fuse_inode *fi = INO_FI(inode);
+ struct fuse_req *req = fuse_get_request(fc);
+ struct fuse_getdir_out_i outarg;
+ int err;
+
+ if (!req)
+ return -ERESTARTSYS;
+
+ req->in.h.opcode = FUSE_GETDIR;
+ req->in.h.nodeid = fi->nodeid;
+ 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;
+ if (!err)
+ err = fuse_checkdir(outarg.file, file);
+ fuse_put_request(fc, req);
+ 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)
+ printk("fuse_readdir: failed to read container file\n");
+ else
+ 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 = INO_FC(inode);
+ struct fuse_inode *fi = INO_FI(inode);
+ struct fuse_req *req = fuse_get_request(fc);
+ char *link;
+
+ if (!req)
+ return ERR_PTR(-ERESTARTSYS);
+
+ 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 = fi->nodeid;
+ 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 int fuse_readlink(struct dentry *dentry, char __user *buffer,
+ int buflen)
+{
+ int ret;
+ char *link;
+
+ link = read_link(dentry);
+ ret = vfs_readlink(dentry, buffer, buflen, link);
+ free_link(link);
+ return ret;
+}
+
+static int fuse_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ int ret;
+ char *link;
+
+ link = read_link(dentry);
+ ret = vfs_follow_link(nd, link);
+ free_link(link);
+ return ret;
+}
+
+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_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
+{
+ if (!entry->d_inode)
+ return 0;
+ else if (entry->d_time && time_after(jiffies, entry->d_time)) {
+ struct inode *inode = entry->d_inode;
+ struct fuse_inode *fi = INO_FI(inode);
+ struct fuse_entry_out outarg;
+ int version;
+ int ret;
+
+ ret = fuse_do_lookup(entry->d_parent->d_inode, entry, &outarg,
+ &version);
+ if (ret)
+ return 0;
+
+ if (outarg.nodeid != fi->nodeid)
+ return 0;
+
+ 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 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)
{
@@ -163,4 +480,28 @@ static struct dentry *fuse_lookup(struct

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_file_inode_operations = {
+ .permission = fuse_permission,
+ .getattr = fuse_getattr,
+};
+
+static struct inode_operations fuse_symlink_inode_operations = {
+ .readlink = fuse_readlink,
+ .follow_link = fuse_follow_link,
+ .getattr = fuse_getattr,
+};
+
+static struct dentry_operations fuse_dentry_operations = {
+ .d_revalidate = fuse_dentry_revalidate,
};
--- linux-2.6.10-rc2/fs/fuse/fuse_i.h 2004-11-20 22:56:25.000000000 +0100
+++ linux-2.6.10-rc2-fuse/fs/fuse/fuse_i.h 2004-11-20 22:56:24.000000000 +0100
@@ -121,6 +121,11 @@ struct fuse_conn {
int reqctr;
};

+struct fuse_getdir_out_i {
+ int fd;
+ void *file; /* Used by kernel only */
+};
+
#define SB_FC(sb) ((sb)->s_fs_info)
#define INO_FC(inode) SB_FC((inode)->i_sb)
#define INO_FI(i) ((struct fuse_inode *) (((struct inode *)(i))+1))
@@ -148,6 +153,8 @@ extern spinlock_t fuse_lock;
struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
int generation, struct fuse_attr *attr, int version);

+struct inode *fuse_ilookup(struct super_block *sb, unsigned long nodeid);
+
/**
* Send FORGET command
*/
@@ -214,3 +221,8 @@ void request_send(struct fuse_conn *fc,
* Send a request for which a reply is not expected
*/
void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
+
+/**
+ * Get the attributes of a file
+ */
+int fuse_do_getattr(struct inode *inode);
--- linux-2.6.10-rc2/fs/fuse/inode.c 2004-11-20 22:56:25.000000000 +0100
+++ linux-2.6.10-rc2-fuse/fs/fuse/inode.c 2004-11-20 22:56:24.000000000 +0100
@@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/parser.h>
+#include <linux/statfs.h>

static kmem_cache_t *fuse_inode_cachep;

@@ -98,6 +99,43 @@ static void fuse_put_super(struct super_
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 = SB_FC(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,
@@ -254,6 +292,7 @@ static struct super_operations fuse_supe
.read_inode = fuse_read_inode,
.clear_inode = fuse_clear_inode,
.put_super = fuse_put_super,
+ .statfs = fuse_statfs,
.show_options = fuse_show_options,
};

--- linux-2.6.10-rc2/include/linux/fuse.h 2004-11-20 22:56:25.000000000 +0100
+++ linux-2.6.10-rc2-fuse/include/linux/fuse.h 2004-11-20 22:56:25.000000000 +0100
@@ -40,14 +40,24 @@ struct fuse_attr {
unsigned long ctimensec;
};

+struct fuse_kstatfs {
+ unsigned int bsize;
+ unsigned long long blocks;
+ unsigned long long bfree;
+ unsigned long long bavail;
+ unsigned long long files;
+ unsigned long long ffree;
+ unsigned int namelen;
+};
+
enum fuse_opcode {
FUSE_LOOKUP = 1,
FUSE_FORGET = 2, /* no reply */
- /* FUSE_GETATTR = 3, */
+ FUSE_GETATTR = 3,
/* FUSE_SETATTR = 4, */
- /* FUSE_READLINK = 5, */
+ FUSE_READLINK = 5,
/* FUSE_SYMLINK = 6, */
- /* FUSE_GETDIR = 7, */
+ FUSE_GETDIR = 7,
/* FUSE_MKNOD = 8, */
/* FUSE_MKDIR = 9, */
/* FUSE_UNLINK = 10, */
@@ -57,7 +67,7 @@ enum fuse_opcode {
/* FUSE_OPEN = 14, */
/* FUSE_READ = 15, */
/* FUSE_WRITE = 16, */
- /* FUSE_STATFS = 17, */
+ FUSE_STATFS = 17,
/* FUSE_RELEASE = 18, */
/* FUSE_INVALIDATE = 19, */
/* FUSE_FSYNC = 20, */
@@ -88,6 +98,20 @@ struct fuse_forget_in {
int version;
};

+struct fuse_attr_out {
+ unsigned long attr_valid; /* Cache timeout for the attributes */
+ unsigned long attr_valid_nsec;
+ struct fuse_attr attr;
+};
+
+struct fuse_getdir_out {
+ int fd;
+};
+
+struct fuse_statfs_out {
+ struct fuse_kstatfs st;
+};
+
struct fuse_in_header {
int unique;
enum fuse_opcode opcode;
@@ -101,3 +125,15 @@ struct fuse_out_header {
int unique;
int error;
};
+
+struct fuse_dirent {
+ unsigned long ino;
+ unsigned short namelen;
+ unsigned char type;
+ char name[256];
+};
+
+#define FUSE_NAME_OFFSET ((unsigned int) ((struct fuse_dirent *) 0)->name)
+#define FUSE_DIRENT_ALIGN(x) (((x) + sizeof(long) - 1) & ~(sizeof(long) - 1))
+#define FUSE_DIRENT_SIZE(d) \
+ FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)
-
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