[PATCH] FUSE - extended attribute operations

This patch adds the extended attribute operations to FUSE.

The following operations are added:

 o getxattr
 o setxattr
 o listxattr
 o removexattr

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

3 files changed, 213 insertions, 0 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 0950455914dd..f127625543b4 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -744,6 +744,177 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
         return d_splice_alias(inode, entry);
 }
 
+static int fuse_setxattr(struct dentry *entry, const char *name,
+                         const void *value, size_t size, int flags)
+{
+        struct inode *inode = entry->d_inode;
+        struct fuse_conn *fc = get_fuse_conn(inode);
+        struct fuse_req *req;
+        struct fuse_setxattr_in inarg;
+        int err;
+
+        if (size > FUSE_XATTR_SIZE_MAX)
+                return -E2BIG;
+
+        if (fc->no_setxattr)
+                return -EOPNOTSUPP;
+
+        req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.size = size;
+        inarg.flags = flags;
+        req->in.h.opcode = FUSE_SETXATTR;
+        req->in.h.nodeid = get_node_id(inode);
+        req->inode = inode;
+        req->in.numargs = 3;
+        req->in.args[0].size = sizeof(inarg);
+        req->in.args[0].value = &inarg;
+        req->in.args[1].size = strlen(name) + 1;
+        req->in.args[1].value = name;
+        req->in.args[2].size = size;
+        req->in.args[2].value = value;
+        request_send(fc, req);
+        err = req->out.h.error;
+        fuse_put_request(fc, req);
+        if (err == -ENOSYS) {
+                fc->no_setxattr = 1;
+                err = -EOPNOTSUPP;
+        }
+        return err;
+}
+
+static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
+                             void *value, size_t size)
+{
+        struct inode *inode = entry->d_inode;
+        struct fuse_conn *fc = get_fuse_conn(inode);
+        struct fuse_req *req;
+        struct fuse_getxattr_in inarg;
+        struct fuse_getxattr_out outarg;
+        ssize_t ret;
+
+        if (fc->no_getxattr)
+                return -EOPNOTSUPP;
+
+        req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.size = size;
+        req->in.h.opcode = FUSE_GETXATTR;
+        req->in.h.nodeid = get_node_id(inode);
+        req->inode = inode;
+        req->in.numargs = 2;
+        req->in.args[0].size = sizeof(inarg);
+        req->in.args[0].value = &inarg;
+        req->in.args[1].size = strlen(name) + 1;
+        req->in.args[1].value = name;
+        /* This is really two different operations rolled into one */
+        req->out.numargs = 1;
+        if (size) {
+                req->out.argvar = 1;
+                req->out.args[0].size = size;
+                req->out.args[0].value = value;
+        } else {
+                req->out.args[0].size = sizeof(outarg);
+                req->out.args[0].value = &outarg;
+        }
+        request_send(fc, req);
+        ret = req->out.h.error;
+        if (!ret)
+                ret = size ? req->out.args[0].size : outarg.size;
+        else {
+                if (ret == -ENOSYS) {
+                        fc->no_getxattr = 1;
+                        ret = -EOPNOTSUPP;
+                }
+        }
+        fuse_put_request(fc, req);
+        return ret;
+}
+
+static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
+{
+        struct inode *inode = entry->d_inode;
+        struct fuse_conn *fc = get_fuse_conn(inode);
+        struct fuse_req *req;
+        struct fuse_getxattr_in inarg;
+        struct fuse_getxattr_out outarg;
+        ssize_t ret;
+
+        if (fc->no_listxattr)
+                return -EOPNOTSUPP;
+
+        req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        memset(&inarg, 0, sizeof(inarg));
+        inarg.size = size;
+        req->in.h.opcode = FUSE_LISTXATTR;
+        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;
+        /* This is really two different operations rolled into one */
+        req->out.numargs = 1;
+        if (size) {
+                req->out.argvar = 1;
+                req->out.args[0].size = size;
+                req->out.args[0].value = list;
+        } else {
+                req->out.args[0].size = sizeof(outarg);
+                req->out.args[0].value = &outarg;
+        }
+        request_send(fc, req);
+        ret = req->out.h.error;
+        if (!ret)
+                ret = size ? req->out.args[0].size : outarg.size;
+        else {
+                if (ret == -ENOSYS) {
+                        fc->no_listxattr = 1;
+                        ret = -EOPNOTSUPP;
+                }
+        }
+        fuse_put_request(fc, req);
+        return ret;
+}
+
+static int fuse_removexattr(struct dentry *entry, const char *name)
+{
+        struct inode *inode = entry->d_inode;
+        struct fuse_conn *fc = get_fuse_conn(inode);
+        struct fuse_req *req;
+        int err;
+
+        if (fc->no_removexattr)
+                return -EOPNOTSUPP;
+
+        req = fuse_get_request(fc);
+        if (!req)
+                return -ERESTARTNOINTR;
+
+        req->in.h.opcode = FUSE_REMOVEXATTR;
+        req->in.h.nodeid = get_node_id(inode);
+        req->inode = inode;
+        req->in.numargs = 1;
+        req->in.args[0].size = strlen(name) + 1;
+        req->in.args[0].value = name;
+        request_send(fc, req);
+        err = req->out.h.error;
+        fuse_put_request(fc, req);
+        if (err == -ENOSYS) {
+                fc->no_removexattr = 1;
+                err = -EOPNOTSUPP;
+        }
+        return err;
+}
+
 static struct inode_operations fuse_dir_inode_operations = {
         .lookup         = fuse_lookup,
         .mkdir          = fuse_mkdir,
@@ -757,6 +928,10 @@ static struct inode_operations fuse_dir_inode_operations = {
         .mknod          = fuse_mknod,
         .permission     = fuse_permission,
         .getattr        = fuse_getattr,
+        .setxattr       = fuse_setxattr,
+        .getxattr       = fuse_getxattr,
+        .listxattr      = fuse_listxattr,
+        .removexattr    = fuse_removexattr,
 };
 
 static struct file_operations fuse_dir_operations = {
@@ -771,6 +946,10 @@ static struct inode_operations fuse_common_inode_operations = {
         .setattr        = fuse_setattr,
         .permission     = fuse_permission,
         .getattr        = fuse_getattr,
+        .setxattr       = fuse_setxattr,
+        .getxattr       = fuse_getxattr,
+        .listxattr      = fuse_listxattr,
+        .removexattr    = fuse_removexattr,
 };
 
 static struct inode_operations fuse_symlink_inode_operations = {
@@ -779,6 +958,10 @@ static struct inode_operations fuse_symlink_inode_operations = {
         .put_link       = fuse_put_link,
         .readlink       = generic_readlink,
         .getattr        = fuse_getattr,
+        .setxattr       = fuse_setxattr,
+        .getxattr       = fuse_getxattr,
+        .listxattr      = fuse_listxattr,
+        .removexattr    = fuse_removexattr,
 };
 
 void fuse_init_common(struct inode *inode)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index c8e6c87496e0..86183c562104 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -245,6 +245,18 @@ struct fuse_conn {
         /** Is flush not implemented by fs? */
         unsigned no_flush : 1;
 
+        /** Is setxattr not implemented by fs? */
+        unsigned no_setxattr : 1;
+
+        /** Is getxattr not implemented by fs? */
+        unsigned no_getxattr : 1;
+
+        /** Is listxattr not implemented by fs? */
+        unsigned no_listxattr : 1;
+
+        /** Is removexattr not implemented by fs? */
+        unsigned no_removexattr : 1;
+
         /** Backing dev info */
         struct backing_dev_info bdi;
 };
diff --git a/include/linux/fuse.h b/include/linux/fuse.h
index 61f34636ffbc..bf564edf9905 100644
--- a/include/linux/fuse.h
+++ b/include/linux/fuse.h
@@ -80,6 +80,10 @@ enum fuse_opcode {
         FUSE_STATFS        = 17,
         FUSE_RELEASE       = 18,
         FUSE_FSYNC         = 20,
+        FUSE_SETXATTR      = 21,
+        FUSE_GETXATTR      = 22,
+        FUSE_LISTXATTR     = 23,
+        FUSE_REMOVEXATTR   = 24,
         FUSE_FLUSH         = 25,
         FUSE_INIT          = 26
 };
@@ -89,6 +93,7 @@ enum fuse_opcode {
 
 #define FUSE_NAME_MAX 1024
 #define FUSE_SYMLINK_MAX 4096
+#define FUSE_XATTR_SIZE_MAX 4096
 
 struct fuse_entry_out {
         __u64   nodeid;         /* Inode ID */
@@ -183,6 +188,19 @@ struct fuse_fsync_in {
         __u32   fsync_flags;
 };
 
+struct fuse_setxattr_in {
+        __u32   size;
+        __u32   flags;
+};
+
+struct fuse_getxattr_in {
+        __u32   size;
+};
+
+struct fuse_getxattr_out {
+        __u32   size;
+};
+
 struct fuse_init_in_out {
         __u32   major;
         __u32   minor;