[PATCH] FUSE - read-write operations

This patch adds the write filesystem operations of FUSE.

The following operations are added:

 o setattr
 o symlink
 o mknod
 o mkdir
 o create
 o unlink
 o rmdir
 o rename
 o link

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 419 insertions, 19 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index a89730e70c58..92c7188ccd16 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -42,7 +42,6 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
                 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);
@@ -53,15 +52,19 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
 
                 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;
+                if (!err) {
+                        if (outarg.nodeid != get_node_id(inode)) {
+                                fuse_send_forget(fc, req, outarg.nodeid, 1);
+                                return 0;
+                        }
+                        fi->nlookup ++;
+                }
                 fuse_put_request(fc, req);
-                if (err || outarg.nodeid != get_node_id(inode) ||
-                    (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
+                if (err || (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,
@@ -78,7 +81,6 @@ 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);
@@ -93,13 +95,12 @@ static int fuse_lookup_iget(struct inode *dir, struct dentry *entry,
 
         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);
+                                  &outarg.attr);
                 if (!inode) {
-                        fuse_send_forget(fc, req, outarg.nodeid, version);
+                        fuse_send_forget(fc, req, outarg.nodeid, 1);
                         return -ENOMEM;
                 }
         }
@@ -120,6 +121,264 @@ static int fuse_lookup_iget(struct inode *dir, struct dentry *entry,
         return 0;
 }
 
+void fuse_invalidate_attr(struct inode *inode)
+{
+        get_fuse_inode(inode)->i_time = jiffies - 1;
+}
+
+static void fuse_invalidate_entry(struct dentry *entry)
+{
+        d_invalidate(entry);
+        entry->d_time = jiffies - 1;
+}
+
+static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
+                            struct inode *dir, struct dentry *entry,
+                            int mode)
+{
+        struct fuse_entry_out outarg;
+        struct inode *inode;
+        struct fuse_inode *fi;
+        int err;
+
+        req->in.h.nodeid = get_node_id(dir);
+        req->inode = dir;
+        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) {
+                fuse_put_request(fc, req);
+                return err;
+        }
+        inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
+                          &outarg.attr);
+        if (!inode) {
+                fuse_send_forget(fc, req, outarg.nodeid, 1);
+                return -ENOMEM;
+        }
+        fuse_put_request(fc, req);
+
+        /* Don't allow userspace to do really stupid things... */
+        if ((inode->i_mode ^ mode) & S_IFMT) {
+                iput(inode);
+                return -EIO;
+        }
+
+        entry->d_time = time_to_jiffies(outarg.entry_valid,
+                                        outarg.entry_valid_nsec);
+
+        fi = get_fuse_inode(inode);
+        fi->i_time = time_to_jiffies(outarg.attr_valid,
+                                     outarg.attr_valid_nsec);
+
+        d_instantiate(entry, inode);
+        fuse_invalidate_attr(dir);
+        return 0;
+}
+
+static int fuse_mknod(struct inode *dir, struct dentry *entry, int mode,
+                      dev_t rdev)
+{
+        struct fuse_mknod_in inarg;
+        struct fuse_conn *fc = get_fuse_conn(dir);
+        struct fuse_req *req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.mode = mode;
+        inarg.rdev = new_encode_dev(rdev);
+        req->in.h.opcode = FUSE_MKNOD;
+        req->in.numargs = 2;
+        req->in.args[0].size = sizeof(inarg);
+        req->in.args[0].value = &inarg;
+        req->in.args[1].size = entry->d_name.len + 1;
+        req->in.args[1].value = entry->d_name.name;
+        return create_new_entry(fc, req, dir, entry, mode);
+}
+
+static int fuse_create(struct inode *dir, struct dentry *entry, int mode,
+                       struct nameidata *nd)
+{
+        return fuse_mknod(dir, entry, mode, 0);
+}
+
+static int fuse_mkdir(struct inode *dir, struct dentry *entry, int mode)
+{
+        struct fuse_mkdir_in inarg;
+        struct fuse_conn *fc = get_fuse_conn(dir);
+        struct fuse_req *req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.mode = mode;
+        req->in.h.opcode = FUSE_MKDIR;
+        req->in.numargs = 2;
+        req->in.args[0].size = sizeof(inarg);
+        req->in.args[0].value = &inarg;
+        req->in.args[1].size = entry->d_name.len + 1;
+        req->in.args[1].value = entry->d_name.name;
+        return create_new_entry(fc, req, dir, entry, S_IFDIR);
+}
+
+static int fuse_symlink(struct inode *dir, struct dentry *entry,
+                        const char *link)
+{
+        struct fuse_conn *fc = get_fuse_conn(dir);
+        unsigned len = strlen(link) + 1;
+        struct fuse_req *req;
+
+        if (len > FUSE_SYMLINK_MAX)
+                return -ENAMETOOLONG;
+
+        req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        req->in.h.opcode = FUSE_SYMLINK;
+        req->in.numargs = 2;
+        req->in.args[0].size = entry->d_name.len + 1;
+        req->in.args[0].value = entry->d_name.name;
+        req->in.args[1].size = len;
+        req->in.args[1].value = link;
+        return create_new_entry(fc, req, dir, entry, S_IFLNK);
+}
+
+static int fuse_unlink(struct inode *dir, struct dentry *entry)
+{
+        int err;
+        struct fuse_conn *fc = get_fuse_conn(dir);
+        struct fuse_req *req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        req->in.h.opcode = FUSE_UNLINK;
+        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;
+        request_send(fc, req);
+        err = req->out.h.error;
+        fuse_put_request(fc, req);
+        if (!err) {
+                struct inode *inode = entry->d_inode;
+
+                /* Set nlink to zero so the inode can be cleared, if
+                   the inode does have more links this will be
+                   discovered at the next lookup/getattr */
+                inode->i_nlink = 0;
+                fuse_invalidate_attr(inode);
+                fuse_invalidate_attr(dir);
+        } else if (err == -EINTR)
+                fuse_invalidate_entry(entry);
+        return err;
+}
+
+static int fuse_rmdir(struct inode *dir, struct dentry *entry)
+{
+        int err;
+        struct fuse_conn *fc = get_fuse_conn(dir);
+        struct fuse_req *req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        req->in.h.opcode = FUSE_RMDIR;
+        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;
+        request_send(fc, req);
+        err = req->out.h.error;
+        fuse_put_request(fc, req);
+        if (!err) {
+                entry->d_inode->i_nlink = 0;
+                fuse_invalidate_attr(dir);
+        } else if (err == -EINTR)
+                fuse_invalidate_entry(entry);
+        return err;
+}
+
+static int fuse_rename(struct inode *olddir, struct dentry *oldent,
+                       struct inode *newdir, struct dentry *newent)
+{
+        int err;
+        struct fuse_rename_in inarg;
+        struct fuse_conn *fc = get_fuse_conn(olddir);
+        struct fuse_req *req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.newdir = get_node_id(newdir);
+        req->in.h.opcode = FUSE_RENAME;
+        req->in.h.nodeid = get_node_id(olddir);
+        req->inode = olddir;
+        req->inode2 = newdir;
+        req->in.numargs = 3;
+        req->in.args[0].size = sizeof(inarg);
+        req->in.args[0].value = &inarg;
+        req->in.args[1].size = oldent->d_name.len + 1;
+        req->in.args[1].value = oldent->d_name.name;
+        req->in.args[2].size = newent->d_name.len + 1;
+        req->in.args[2].value = newent->d_name.name;
+        request_send(fc, req);
+        err = req->out.h.error;
+        fuse_put_request(fc, req);
+        if (!err) {
+                fuse_invalidate_attr(olddir);
+                if (olddir != newdir)
+                        fuse_invalidate_attr(newdir);
+        } else if (err == -EINTR) {
+                /* If request was interrupted, DEITY only knows if the
+                   rename actually took place.  If the invalidation
+                   fails (e.g. some process has CWD under the renamed
+                   directory), then there can be inconsistency between
+                   the dcache and the real filesystem.  Tough luck. */
+                fuse_invalidate_entry(oldent);
+                if (newent->d_inode)
+                        fuse_invalidate_entry(newent);
+        }
+
+        return err;
+}
+
+static int fuse_link(struct dentry *entry, struct inode *newdir,
+                     struct dentry *newent)
+{
+        int err;
+        struct fuse_link_in inarg;
+        struct inode *inode = entry->d_inode;
+        struct fuse_conn *fc = get_fuse_conn(inode);
+        struct fuse_req *req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.oldnodeid = get_node_id(inode);
+        req->in.h.opcode = FUSE_LINK;
+        req->inode2 = inode;
+        req->in.numargs = 2;
+        req->in.args[0].size = sizeof(inarg);
+        req->in.args[0].value = &inarg;
+        req->in.args[1].size = newent->d_name.len + 1;
+        req->in.args[1].value = newent->d_name.name;
+        err = create_new_entry(fc, req, newdir, newent, inode->i_mode);
+        /* Contrary to "normal" filesystems it can happen that link
+           makes two "logical" inodes point to the same "physical"
+           inode.  We invalidate the attributes of the old one, so it
+           will reflect changes in the backing inode (link count,
+           etc.)
+        */
+        if (!err || err == -EINTR)
+                fuse_invalidate_attr(inode);
+        return err;
+}
+
 int fuse_do_getattr(struct inode *inode)
 {
         int err;
@@ -341,6 +600,91 @@ static int fuse_dir_release(struct inode *inode, struct file *file)
         return 0;
 }
 
+static unsigned iattr_to_fattr(struct iattr *iattr, struct fuse_attr *fattr)
+{
+        unsigned ivalid = iattr->ia_valid;
+        unsigned fvalid = 0;
+
+        memset(fattr, 0, sizeof(*fattr));
+
+        if (ivalid & ATTR_MODE)
+                fvalid |= FATTR_MODE,   fattr->mode = iattr->ia_mode;
+        if (ivalid & ATTR_UID)
+                fvalid |= FATTR_UID,    fattr->uid = iattr->ia_uid;
+        if (ivalid & ATTR_GID)
+                fvalid |= FATTR_GID,    fattr->gid = iattr->ia_gid;
+        if (ivalid & ATTR_SIZE)
+                fvalid |= FATTR_SIZE,   fattr->size = iattr->ia_size;
+        /* You can only _set_ these together (they may change by themselves) */
+        if ((ivalid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME)) {
+                fvalid |= FATTR_ATIME | FATTR_MTIME;
+                fattr->atime = iattr->ia_atime.tv_sec;
+                fattr->mtime = iattr->ia_mtime.tv_sec;
+        }
+
+        return fvalid;
+}
+
+static int fuse_setattr(struct dentry *entry, struct iattr *attr)
+{
+        struct inode *inode = entry->d_inode;
+        struct fuse_conn *fc = get_fuse_conn(inode);
+        struct fuse_inode *fi = get_fuse_inode(inode);
+        struct fuse_req *req;
+        struct fuse_setattr_in inarg;
+        struct fuse_attr_out outarg;
+        int err;
+        int is_truncate = 0;
+
+        if (attr->ia_valid & ATTR_SIZE) {
+                unsigned long limit;
+                is_truncate = 1;
+                limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+                if (limit != RLIM_INFINITY && attr->ia_size > (loff_t) limit) {
+                        send_sig(SIGXFSZ, current, 0);
+                        return -EFBIG;
+                }
+        }
+
+        req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.valid = iattr_to_fattr(attr, &inarg.attr);
+        req->in.h.opcode = FUSE_SETATTR;
+        req->in.h.nodeid = get_node_id(inode);
+        req->inode = inode;
+        req->in.numargs = 1;
+        req->in.args[0].size = sizeof(inarg);
+        req->in.args[0].value = &inarg;
+        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;
+        fuse_put_request(fc, req);
+        if (!err) {
+                if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
+                        make_bad_inode(inode);
+                        err = -EIO;
+                } else {
+                        if (is_truncate) {
+                                loff_t origsize = i_size_read(inode);
+                                i_size_write(inode, outarg.attr.size);
+                                if (origsize > outarg.attr.size)
+                                        vmtruncate(inode, outarg.attr.size);
+                        }
+                        fuse_change_attributes(inode, &outarg.attr);
+                        fi->i_time = time_to_jiffies(outarg.attr_valid,
+                                                     outarg.attr_valid_nsec);
+                }
+        } else if (err == -EINTR)
+                fuse_invalidate_attr(inode);
+
+        return err;
+}
+
 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
                         struct kstat *stat)
 {
@@ -373,6 +717,15 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 
 static struct inode_operations fuse_dir_inode_operations = {
         .lookup         = fuse_lookup,
+        .mkdir          = fuse_mkdir,
+        .symlink        = fuse_symlink,
+        .unlink         = fuse_unlink,
+        .rmdir          = fuse_rmdir,
+        .rename         = fuse_rename,
+        .link           = fuse_link,
+        .setattr        = fuse_setattr,
+        .create         = fuse_create,
+        .mknod          = fuse_mknod,
         .permission     = fuse_permission,
         .getattr        = fuse_getattr,
 };
@@ -385,11 +738,13 @@ static struct file_operations fuse_dir_operations = {
 };
 
 static struct inode_operations fuse_common_inode_operations = {
+        .setattr        = fuse_setattr,
         .permission     = fuse_permission,
         .getattr        = fuse_getattr,
 };
 
 static struct inode_operations fuse_symlink_inode_operations = {
+        .setattr        = fuse_setattr,
         .follow_link    = fuse_follow_link,
         .put_link       = fuse_put_link,
         .readlink       = generic_readlink,
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 8d91e1492f96..87d25b8f2dc1 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -30,6 +30,9 @@ struct fuse_inode {
          * and kernel */
         u64 nodeid;
 
+        /** Number of lookups on this inode */
+        u64 nlookup;
+
         /** The request used for sending the FORGET message */
         struct fuse_req *forget_req;
 
@@ -252,13 +255,13 @@ 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);
+                        int generation, struct fuse_attr *attr);
 
 /**
  * Send FORGET command
  */
 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
-                      unsigned long nodeid, int version);
+                      unsigned long nodeid, u64 nlookup);
 
 /**
  * Initialise inode operations on regular files and special files
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 41498a1952a0..fa03f80806e5 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -51,6 +51,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb)
         fi = get_fuse_inode(inode);
         fi->i_time = jiffies - 1;
         fi->nodeid = 0;
+        fi->nlookup = 0;
         fi->forget_req = fuse_request_alloc();
         if (!fi->forget_req) {
                 kmem_cache_free(fuse_inode_cachep, inode);
@@ -74,10 +75,10 @@ static void fuse_read_inode(struct inode *inode)
 }
 
 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
-                      unsigned long nodeid, int version)
+                      unsigned long nodeid, u64 nlookup)
 {
         struct fuse_forget_in *inarg = &req->misc.forget_in;
-        inarg->version = version;
+        inarg->nlookup = nlookup;
         req->in.h.opcode = FUSE_FORGET;
         req->in.h.nodeid = nodeid;
         req->in.numargs = 1;
@@ -91,7 +92,7 @@ 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);
+                fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
                 fi->forget_req = NULL;
         }
 }
@@ -156,9 +157,10 @@ static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 }
 
 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
-                        int generation, struct fuse_attr *attr, int version)
+                        int generation, struct fuse_attr *attr)
 {
         struct inode *inode;
+        struct fuse_inode *fi;
         struct fuse_conn *fc = get_fuse_conn_super(sb);
         int retried = 0;
 
@@ -181,8 +183,9 @@ struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
                 goto retry;
         }
 
+        fi = get_fuse_inode(inode);
+        fi->nlookup ++;
         fuse_change_attributes(inode, attr);
-        inode->i_version = version;
         return inode;
 }
 
@@ -389,7 +392,7 @@ static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
 
         attr.mode = mode;
         attr.ino = FUSE_ROOT_ID;
-        return fuse_iget(sb, 1, 0, &attr, 0);
+        return fuse_iget(sb, 1, 0, &attr);
 }
 
 static struct super_operations fuse_super_operations = {
diff --git a/include/linux/fuse.h b/include/linux/fuse.h
index 21b9ba16f8d5..19d69a3e1623 100644
--- a/include/linux/fuse.h
+++ b/include/linux/fuse.h
@@ -11,7 +11,7 @@
 #include <asm/types.h>
 
 /** Version number of this interface */
-#define FUSE_KERNEL_VERSION 6
+#define FUSE_KERNEL_VERSION 7
 
 /** Minor version number of this interface */
 #define FUSE_KERNEL_MINOR_VERSION 1
@@ -52,12 +52,28 @@ struct fuse_kstatfs {
         __u32   namelen;
 };
 
+#define FATTR_MODE      (1 << 0)
+#define FATTR_UID       (1 << 1)
+#define FATTR_GID       (1 << 2)
+#define FATTR_SIZE      (1 << 3)
+#define FATTR_ATIME     (1 << 4)
+#define FATTR_MTIME     (1 << 5)
+#define FATTR_CTIME     (1 << 6)
+
 enum fuse_opcode {
         FUSE_LOOKUP        = 1,
         FUSE_FORGET        = 2,  /* no reply */
         FUSE_GETATTR       = 3,
+        FUSE_SETATTR       = 4,
         FUSE_READLINK      = 5,
+        FUSE_SYMLINK       = 6,
         FUSE_GETDIR        = 7,
+        FUSE_MKNOD         = 8,
+        FUSE_MKDIR         = 9,
+        FUSE_UNLINK        = 10,
+        FUSE_RMDIR         = 11,
+        FUSE_RENAME        = 12,
+        FUSE_LINK          = 13,
         FUSE_STATFS        = 17,
         FUSE_INIT          = 26
 };
@@ -66,6 +82,7 @@ enum fuse_opcode {
 #define FUSE_MAX_IN 8192
 
 #define FUSE_NAME_MAX 1024
+#define FUSE_SYMLINK_MAX 4096
 
 struct fuse_entry_out {
         __u64   nodeid;         /* Inode ID */
@@ -79,7 +96,7 @@ struct fuse_entry_out {
 };
 
 struct fuse_forget_in {
-        __u64   version;
+        __u64   nlookup;
 };
 
 struct fuse_attr_out {
@@ -93,6 +110,28 @@ struct fuse_getdir_out {
         __u32   fd;
 };
 
+struct fuse_mknod_in {
+        __u32   mode;
+        __u32   rdev;
+};
+
+struct fuse_mkdir_in {
+        __u32   mode;
+};
+
+struct fuse_rename_in {
+        __u64   newdir;
+};
+
+struct fuse_link_in {
+        __u64   oldnodeid;
+};
+
+struct fuse_setattr_in {
+        __u32   valid;
+        struct fuse_attr attr;
+};
+
 struct fuse_statfs_out {
         struct fuse_kstatfs st;
 };