fuse: add support for mandatory locking
Miklos Szeredi [Thu, 18 Oct 2007 10:07:04 +0000 (03:07 -0700)]
For mandatory locking the userspace filesystem needs to know the lock
ownership for read, write and truncate operations.

This patch adds the necessary fields to the protocol.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fuse/dir.c
fs/fuse/file.c
fs/fuse/fuse_i.h
include/linux/fuse.h

index 052327b..6c83ed0 100644 (file)
@@ -1108,6 +1108,11 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
                inarg.valid |= FATTR_FH;
                inarg.fh = ff->fh;
        }
+       if (attr->ia_valid & ATTR_SIZE) {
+               /* For mandatory locking in truncate */
+               inarg.valid |= FATTR_LOCKOWNER;
+               inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
+       }
        req->in.h.opcode = FUSE_SETATTR;
        req->in.h.nodeid = get_node_id(inode);
        req->in.numargs = 1;
index 2b589de..0fcdba9 100644 (file)
@@ -189,7 +189,7 @@ static int fuse_release(struct inode *inode, struct file *file)
  * Scramble the ID space with XTEA, so that the value of the files_struct
  * pointer is not exposed to userspace.
  */
-static u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
+u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 {
        u32 *k = fc->scramble_key;
        u64 v = (unsigned long) id;
@@ -308,11 +308,19 @@ void fuse_read_fill(struct fuse_req *req, struct fuse_file *ff,
 }
 
 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
-                            struct inode *inode, loff_t pos, size_t count)
+                            struct inode *inode, loff_t pos, size_t count,
+                            fl_owner_t owner)
 {
        struct fuse_conn *fc = get_fuse_conn(inode);
        struct fuse_file *ff = file->private_data;
+
        fuse_read_fill(req, ff, inode, pos, count, FUSE_READ);
+       if (owner != NULL) {
+               struct fuse_read_in *inarg = &req->misc.read_in;
+
+               inarg->read_flags |= FUSE_READ_LOCKOWNER;
+               inarg->lock_owner = fuse_lock_owner_id(fc, owner);
+       }
        request_send(fc, req);
        return req->out.args[0].size;
 }
@@ -336,7 +344,8 @@ static int fuse_readpage(struct file *file, struct page *page)
        req->out.page_zeroing = 1;
        req->num_pages = 1;
        req->pages[0] = page;
-       fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE);
+       fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE,
+                      NULL);
        err = req->out.h.error;
        fuse_put_request(fc, req);
        if (!err)
@@ -447,6 +456,7 @@ static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
                            struct inode *inode, loff_t pos, size_t count,
                            int writepage)
 {
+       struct fuse_conn *fc = get_fuse_conn(inode);
        struct fuse_write_in *inarg = &req->misc.write.in;
        struct fuse_write_out *outarg = &req->misc.write.out;
 
@@ -459,7 +469,10 @@ static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
        req->in.h.nodeid = get_node_id(inode);
        req->in.argpages = 1;
        req->in.numargs = 2;
-       req->in.args[0].size = sizeof(struct fuse_write_in);
+       if (fc->minor < 9)
+               req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
+       else
+               req->in.args[0].size = sizeof(struct fuse_write_in);
        req->in.args[0].value = inarg;
        req->in.args[1].size = count;
        req->out.numargs = 1;
@@ -468,10 +481,16 @@ static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 }
 
 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
-                             struct inode *inode, loff_t pos, size_t count)
+                             struct inode *inode, loff_t pos, size_t count,
+                             fl_owner_t owner)
 {
        struct fuse_conn *fc = get_fuse_conn(inode);
        fuse_write_fill(req, file->private_data, inode, pos, count, 0);
+       if (owner != NULL) {
+               struct fuse_write_in *inarg = &req->misc.write.in;
+               inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
+               inarg->lock_owner = fuse_lock_owner_id(fc, owner);
+       }
        request_send(fc, req);
        return req->misc.write.out.size;
 }
@@ -508,7 +527,7 @@ static int fuse_buffered_write(struct file *file, struct inode *inode,
        req->num_pages = 1;
        req->pages[0] = page;
        req->page_offset = offset;
-       nres = fuse_send_write(req, file, inode, pos, count);
+       nres = fuse_send_write(req, file, inode, pos, count, NULL);
        err = req->out.h.error;
        fuse_put_request(fc, req);
        if (!err && !nres)
@@ -609,9 +628,11 @@ static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
                nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
                nbytes = min(count, nbytes);
                if (write)
-                       nres = fuse_send_write(req, file, inode, pos, nbytes);
+                       nres = fuse_send_write(req, file, inode, pos, nbytes,
+                                              current->files);
                else
-                       nres = fuse_send_read(req, file, inode, pos, nbytes);
+                       nres = fuse_send_read(req, file, inode, pos, nbytes,
+                                             current->files);
                fuse_release_user_pages(req, !write);
                if (req->out.h.error) {
                        if (!res)
index 8b64a63..6c5461d 100644 (file)
@@ -591,3 +591,5 @@ int fuse_valid_type(int m);
  * Is task allowed to perform filesystem operation?
  */
 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
+
+u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
index 6f4a312..7d4fa5b 100644 (file)
@@ -14,6 +14,7 @@
  * 7.9:
  *  - new fuse_getattr_in input argument of GETATTR
  *  - add lk_flags in fuse_lk_in
+ *  - add lock_owner field to fuse_setattr_in, fuse_read_in and fuse_write_in
  */
 
 #include <asm/types.h>
@@ -86,6 +87,7 @@ struct fuse_file_lock {
 #define FATTR_FH       (1 << 6)
 #define FATTR_ATIME_NOW        (1 << 7)
 #define FATTR_MTIME_NOW        (1 << 8)
+#define FATTR_LOCKOWNER        (1 << 9)
 
 /**
  * Flags returned by the OPEN request
@@ -123,8 +125,15 @@ struct fuse_file_lock {
  * WRITE flags
  *
  * FUSE_WRITE_CACHE: delayed write from page cache, file handle is guessed
+ * FUSE_WRITE_LOCKOWNER: lock_owner field is valid
  */
 #define FUSE_WRITE_CACHE       (1 << 0)
+#define FUSE_WRITE_LOCKOWNER   (1 << 1)
+
+/**
+ * Read flags
+ */
+#define FUSE_READ_LOCKOWNER    (1 << 1)
 
 enum fuse_opcode {
        FUSE_LOOKUP        = 1,
@@ -219,7 +228,7 @@ struct fuse_setattr_in {
        __u32   padding;
        __u64   fh;
        __u64   size;
-       __u64   unused1;
+       __u64   lock_owner;
        __u64   atime;
        __u64   mtime;
        __u64   unused2;
@@ -262,14 +271,18 @@ struct fuse_read_in {
        __u64   fh;
        __u64   offset;
        __u32   size;
-       __u32   padding;
+       __u32   read_flags;
+       __u64   lock_owner;
 };
 
+#define FUSE_COMPAT_WRITE_IN_SIZE 24
+
 struct fuse_write_in {
        __u64   fh;
        __u64   offset;
        __u32   size;
        __u32   write_flags;
+       __u64   lock_owner;
 };
 
 struct fuse_write_out {