fuse: continue to send FUSE_RELEASEDIR when FUSE_OPEN returns ENOSYS

When FUSE_OPEN returns ENOSYS, the no_open bit is set on the connection. Because the FUSE_RELEASE and FUSE_RELEASEDIR paths share code, this incorrectly caused the FUSE_RELEASEDIR request to be dropped and never sent to userspace. Pass an isdir bool to distinguish between FUSE_RELEASE and FUSE_RELEASEDIR inside of fuse_file_put.

Fixes 7678ac50615d ("fuse: support clients that don't implement 'open'")

---
 fs/fuse/dir.c    |  2 +-
 fs/fuse/file.c   | 20 ++++++++++----------
 fs/fuse/fuse_i.h |  2 +-
 3 files changed, 12 insertions(+), 12 deletions(-)

fs/fuse/dir.c +1 -1

index f79aaca30efa..45322408e029 100644
@@ -1462,7 +1462,7 @@ static int fuse_dir_open(struct inode *inode, struct file *file)
 
 static int fuse_dir_release(struct inode *inode, struct file *file)
 {
-       fuse_release_common(file, FUSE_RELEASEDIR);
+       fuse_release_common(file, FUSE_RELEASEDIR, true);
 
        return 0;
 }

fs/fuse/file.c +2 -2

index a201fb0ac64f..defd635adf01 100644
@@ -86,12 +86,12 @@ static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
        iput(req->misc.release.inode);
 }
 
-static void fuse_file_put(struct fuse_file *ff, bool sync)
+static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
 {
        if (refcount_dec_and_test(&ff->count)) {
                struct fuse_req *req = ff->reserved_req;
 
-               if (ff->fc->no_open) {
+               if (ff->fc->no_open && !isdir) {
                        /*
                         * Drop the release request when client does not
                         * implement 'open'

fs/fuse/file.c +7 -7

 {
        struct fuse_file *ff = file->private_data;
        struct fuse_req *req = ff->reserved_req;

@@ -269,7 +269,7 @@ void fuse_release_common(struct file *file, int opcode)
         * synchronous RELEASE is allowed (and desirable) in this case
         * because the server can be trusted not to screw up.
         */
-       fuse_file_put(ff, ff->fc->destroy_req != NULL);
+       fuse_file_put(ff, ff->fc->destroy_req != NULL, isdir);
 }
 
 static int fuse_open(struct inode *inode, struct file *file)

@@ -285,7 +285,7 @@ static int fuse_release(struct inode *inode, struct file *file)
        if (fc->writeback_cache)
                write_inode_now(inode, 1);
 
-       fuse_release_common(file, FUSE_RELEASE);
+       fuse_release_common(file, FUSE_RELEASE, false);
 
        /* return value is ignored by VFS */
        return 0;

@@ -299,7 +299,7 @@ void fuse_sync_release(struct fuse_file *ff, int flags)
         * iput(NULL) is a no-op and since the refcount is 1 and everything's
         * synchronous, we are fine with not doing igrab() here"
         */
-       fuse_file_put(ff, true);
+       fuse_file_put(ff, true, false);
 }
 EXPORT_SYMBOL_GPL(fuse_sync_release);
 

@@ -804,7 +804,7 @@ static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
                put_page(page);
        }
        if (req->ff)
-               fuse_file_put(req->ff, false);
+               fuse_file_put(req->ff, false, false);
 }
 
 static void fuse_send_readpages(struct fuse_req *req, struct file *file)

@@ -1457,7 +1457,7 @@ static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
                __free_page(req->pages[i]);
 
        if (req->ff)
-               fuse_file_put(req->ff, false);
+               fuse_file_put(req->ff, false, false);
 }
 
 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)

@@ -1614,7 +1614,7 @@ int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
        ff = __fuse_write_file_get(fc, fi);
        err = fuse_flush_times(inode, ff);
        if (ff)
-               fuse_file_put(ff, 0);
+               fuse_file_put(ff, 0, false);
 
        return err;
 }

@@ -1928,7 +1928,7 @@ static int fuse_writepages(struct address_space *mapping,
                err = 0;
        }
        if (data.ff)
-               fuse_file_put(data.ff, false);
+               fuse_file_put(data.ff, false, false);
 
        kfree(data.orig_pages);
 out:

fs/fuse/fuse_i.h +1 -2

index b2c388b00888..668bb16dd553 100644
@@ -742,7 +742,7 @@ void fuse_sync_release(struct fuse_file *ff, int flags);
 /**
  * Send RELEASE or RELEASEDIR request
  */
-void fuse_release_common(struct file *file, int opcode);
+void fuse_release_common(struct file *file, int opcode, bool isdir);
 
 /**
  * Send FSYNC or FSYNCDIR request
--

2.17.1

Quoted 7 lines · Chad Austin

When FUSE_OPEN returns ENOSYS, the no_open bit is set on the connection. Because the FUSE_RELEASE and FUSE_RELEASEDIR paths share code, this incorrectly caused the FUSE_RELEASEDIR request to be dropped and never sent to userspace. Pass an isdir bool to distinguish between FUSE_RELEASE and FUSE_RELEASEDIR inside of fuse_file_put.

Quoted 1 line

Fixes 7678ac50615d ("fuse: support clients that don't implement 'open'")

Thanks.

You did not add a Signed-off-by. Can I add it for you?

opcode and isdir are redundant. I've fixed it up (kept isdir) to match fuse_open_common() signature.