cache ENOSYS on some optional functions

7 files changed, 74 insertions, 10 deletions

diff --git a/ChangeLog b/ChangeLog
index 3d32987..da590de 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,6 +10,9 @@
 	background if mount is successful.  '-f' and '-d' options disable
 	backgrounding.  This fixes the "Why does my FUSE daemon hang?"
 	newbie complaint.
+
+	* Cache ENOSYS (function not implemented) errors on *xattr, flush
+	and fsync
 	
 2004-05-18  Miklos Szeredi <mszeredi@inf.bme.hu>
 
diff --git a/include/fuse.h b/include/fuse.h
index e3e4333..d298cb3 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -103,7 +103,7 @@ typedef int (*fuse_dirfil_t) (fuse_dirh_t h, const char *name, int type);
  *  then set the callback pointer to NULL.
  * 
  *  - fsync() has a boolean 'datasync' parameter which if TRUE then do
- *  an fdatasync() operation.  
+ *  an fdatasync() operation.  Implementing this call is optional.
  */
 struct fuse_operations {
     int (*getattr)     (const char *, struct stat *);
diff --git a/kernel/dev.c b/kernel/dev.c
index afc9f4c..af20de8 100644
--- a/kernel/dev.c
+++ b/kernel/dev.c
@@ -543,6 +543,7 @@ static struct fuse_conn *new_conn(void)
 
 	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
 	if (fc != NULL) {
+		memset(fc, 0, sizeof(*fc));
 		fc->sb = NULL;
 		fc->file = NULL;
 		fc->flags = 0;
diff --git a/kernel/dir.c b/kernel/dir.c
index 110a472..e941e3e 100644
--- a/kernel/dir.c
+++ b/kernel/dir.c
@@ -783,6 +783,9 @@ static int fuse_setxattr(struct dentry *entry, const char *name,
 	if (size > FUSE_XATTR_SIZE_MAX)
 		return -E2BIG;
 
+	if (fc->no_setxattr)
+		return -EOPNOTSUPP;
+
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.size = size;
 	inarg.flags = flags;
@@ -797,6 +800,10 @@ static int fuse_setxattr(struct dentry *entry, const char *name,
 	in.args[2].size = size;
 	in.args[2].value = value;
 	request_send(fc, &in, &out);
+	if (out.h.error == -ENOSYS) {
+		fc->no_setxattr = 1;
+		return -EOPNOTSUPP;
+	}
 	return out.h.error;
 }
 
@@ -810,6 +817,9 @@ static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
 	struct fuse_getxattr_in inarg;
 	struct fuse_getxattr_out outarg;
 
+	if (fc->no_getxattr)
+		return -EOPNOTSUPP;
+
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.size = size;
 	
@@ -833,8 +843,13 @@ static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
 	request_send(fc, &in, &out);
 	if (!out.h.error)
 		return size ? out.args[0].size : outarg.size;
-	else
+	else {
+		if (out.h.error == -ENOSYS) {
+			fc->no_getxattr = 1;
+			return -EOPNOTSUPP;
+		}
 		return out.h.error;
+	}
 }
 
 static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
@@ -846,6 +861,9 @@ static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
 	struct fuse_getxattr_in inarg;
 	struct fuse_getxattr_out outarg;
 
+	if (fc->no_listxattr)
+		return -EOPNOTSUPP;
+
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.size = size;
 	
@@ -867,8 +885,13 @@ static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
 	request_send(fc, &in, &out);
 	if (!out.h.error)
 		return size ? out.args[0].size : outarg.size;
-	else
+	else {
+		if (out.h.error == -ENOSYS) {
+			fc->no_listxattr = 1;
+			return -EOPNOTSUPP;
+		}
 		return out.h.error;
+	}
 }
 
 static int fuse_removexattr(struct dentry *entry, const char *name)
@@ -878,12 +901,19 @@ static int fuse_removexattr(struct dentry *entry, const char *name)
 	struct fuse_in in = FUSE_IN_INIT;
 	struct fuse_out out = FUSE_OUT_INIT;
 	
+	if (fc->no_removexattr)
+		return -EOPNOTSUPP;
+
 	in.h.opcode = FUSE_REMOVEXATTR;
 	in.h.ino = inode->i_ino;
 	in.numargs = 1;
 	in.args[0].size = strlen(name) + 1;
 	in.args[0].value = name;
 	request_send(fc, &in, &out);
+	if (out.h.error == -ENOSYS) {
+		fc->no_removexattr = 1;
+		return -EOPNOTSUPP;
+	}
 	return out.h.error;
 	
 }
diff --git a/kernel/file.c b/kernel/file.c
index c9a44fd..2067bd7 100644
--- a/kernel/file.c
+++ b/kernel/file.c
@@ -99,11 +99,16 @@ static int fuse_flush(struct file *file)
 	struct fuse_in in = FUSE_IN_INIT;
 	struct fuse_out out = FUSE_OUT_INIT;
 	
+	if (fc->no_flush)
+		return 0;
+
 	in.h.opcode = FUSE_FLUSH;
 	in.h.ino = inode->i_ino;
 	request_send(fc, &in, &out);
-	if (out.h.error == -ENOSYS)
+	if (out.h.error == -ENOSYS) {
+		fc->no_flush = 1;
 		return 0;
+	}
 	else
 		return out.h.error;
 }
@@ -116,6 +121,9 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 	struct fuse_out out = FUSE_OUT_INIT;
 	struct fuse_fsync_in inarg;
 	
+	if (fc->no_fsync)
+		return 0;
+
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.datasync = datasync;
 
@@ -125,6 +133,11 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 	in.args[0].size = sizeof(inarg);
 	in.args[0].value = &inarg;
 	request_send(fc, &in, &out);
+
+	if (out.h.error == -ENOSYS) {
+		fc->no_fsync = 1;
+		return 0;
+	}
 	return out.h.error;
 
 	/* FIXME: need to ensure, that all write requests issued
diff --git a/kernel/fuse_i.h b/kernel/fuse_i.h
index 1299139..d5943a9 100644
--- a/kernel/fuse_i.h
+++ b/kernel/fuse_i.h
@@ -96,6 +96,24 @@ struct fuse_conn {
 	
 	/** The next unique request id */
 	int reqctr;
+	
+	/** Is fsync not implemented by fs? */
+	unsigned int no_fsync : 1;
+
+	/** Is flush not implemented by fs? */
+	unsigned int no_flush : 1;
+
+	/** Is setxattr not implemented by fs? */
+	unsigned int no_setxattr : 1;
+
+	/** Is getxattr not implemented by fs? */
+	unsigned int no_getxattr : 1;
+
+	/** Is listxattr not implemented by fs? */
+	unsigned int no_listxattr : 1;
+
+	/** Is removexattr not implemented by fs? */
+	unsigned int no_removexattr : 1;
 };
 
 /** One input argument of a request */
diff --git a/lib/fuse.c b/lib/fuse.c
index 255a24b..05d9713 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -980,8 +980,7 @@ static void do_fsync(struct fuse *f, struct fuse_in_header *in,
     res = -ENOENT;
     path = get_path(f, in->ino);
     if(path != NULL) {
-        /* fsync is not mandatory, so don't return ENOSYS */
-        res = 0;
+        res = -ENOSYS;
         if(f->op.fsync)
             res = f->op.fsync(path, inarg->datasync);
         free(path);
@@ -1000,7 +999,7 @@ static void do_setxattr(struct fuse *f, struct fuse_in_header *in,
     res = -ENOENT;
     path = get_path(f, in->ino);
     if (path != NULL) {
-        res = -EOPNOTSUPP; /* or is it ENOTSUPP ??? */
+        res = -ENOSYS;
         if (f->op.setxattr)
             res = f->op.setxattr(path, name, value, arg->size, arg->flags);
         free(path);
@@ -1017,7 +1016,7 @@ static int common_getxattr(struct fuse *f, struct fuse_in_header *in,
     res = -ENOENT;
     path = get_path(f, in->ino);
     if (path != NULL) {
-        res = -EOPNOTSUPP; /* or is it ENOTSUPP ??? */
+        res = -ENOSYS;
         if (f->op.getxattr)
             res = f->op.getxattr(path, name, value, size);
         free(path);
@@ -1081,7 +1080,7 @@ static int common_listxattr(struct fuse *f, struct fuse_in_header *in,
     res = -ENOENT;
     path = get_path(f, in->ino);
     if (path != NULL) {
-        res = -EOPNOTSUPP; /* or is it ENOTSUPP ??? */
+        res = -ENOSYS;
         if (f->op.listxattr)
             res = f->op.listxattr(path, list, size);
         free(path);
@@ -1142,7 +1141,7 @@ static void do_removexattr(struct fuse *f, struct fuse_in_header *in,
     res = -ENOENT;
     path = get_path(f, in->ino);
     if (path != NULL) {
-        res = -EOPNOTSUPP; /* or is it ENOTSUPP ??? */
+        res = -ENOSYS;
         if (f->op.removexattr)
             res = f->op.removexattr(path, name);
         free(path);