NFSv4: fix open failure with O_ACCMODE flag

open() with O_ACCMODE|O_DIRECT flags secondly will fail.

Reproducer:
  1. mount -t nfs -o vers=4.2 $server_ip:/ /mnt/
  2. fd = open("/mnt/file", O_ACCMODE|O_DIRECT|O_CREAT)
  3. close(fd)
  4. fd = open("/mnt/file", O_ACCMODE|O_DIRECT)

Server nfsd4_decode_share_access() will fail with error nfserr_bad_xdr when
client use incorrect share access mode of 0.

Fix this by using NFS4_SHARE_ACCESS_BOTH share access mode in client,
just like firstly opening.

Fixes: ce4ef7c0a8a05 ("NFS: Split out NFS v4 file operations")
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index bac4cf1..0365063 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1991,16 +1991,6 @@ const struct dentry_operations nfs4_dentry_operations = {
 };
 EXPORT_SYMBOL_GPL(nfs4_dentry_operations);
 
-static fmode_t flags_to_mode(int flags)
-{
-       fmode_t res = (__force fmode_t)flags & FMODE_EXEC;
-       if ((flags & O_ACCMODE) != O_WRONLY)
-               res |= FMODE_READ;
-       if ((flags & O_ACCMODE) != O_RDONLY)
-               res |= FMODE_WRITE;
-       return res;
-}
-
 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags, struct file *filp)
 {
        return alloc_nfs_open_context(dentry, flags_to_mode(open_flags), filp);

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 57b0497..7eefa16 100644 (file)
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -42,6 +42,16 @@ static inline bool nfs_lookup_is_soft_revalidate(const struct dentry *dentry)
        return true;
 }
 
+static inline fmode_t flags_to_mode(int flags)
+{
+       fmode_t res = (__force fmode_t)flags & FMODE_EXEC;
+       if ((flags & O_ACCMODE) != O_WRONLY)
+               res |= FMODE_READ;
+       if ((flags & O_ACCMODE) != O_RDONLY)
+               res |= FMODE_WRITE;
+       return res;
+}
+
 /*
  * Note: RFC 1813 doesn't limit the number of auth flavors that
  * a server can return, so make something up.

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index f336d0a..7b861e4 100644 (file)
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -32,6 +32,7 @@ nfs4_file_open(struct inode *inode, struct file *filp)
        struct dentry *parent = NULL;
        struct inode *dir;
        unsigned openflags = filp->f_flags;
+       fmode_t f_mode;
        struct iattr attr;
        int err;
 
@@ -50,8 +51,9 @@ nfs4_file_open(struct inode *inode, struct file *filp)
        if (err)
                return err;
 
+       f_mode = filp->f_mode;
        if ((openflags & O_ACCMODE) == 3)
-               openflags--;
+               f_mode |= flags_to_mode(openflags);
 
        /* We can't create new files here */
        openflags &= ~(O_CREAT|O_EXCL);
@@ -59,7 +61,7 @@ nfs4_file_open(struct inode *inode, struct file *filp)
        parent = dget_parent(dentry);
        dir = d_inode(parent);
 
-       ctx = alloc_nfs_open_context(file_dentry(filp), filp->f_mode, filp);
+       ctx = alloc_nfs_open_context(file_dentry(filp), f_mode, filp);
        err = PTR_ERR(ctx);
        if (IS_ERR(ctx))
                goto out;