[PATCH v4 3/7] CIFS: Add O_DENY* open flags support

[Pavel Shilovsky <piastry@xxxxxxxxxxx>]

Construct share_access value from O_DENY* flags and send it to
the server.

Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
---
 fs/cifs/cifsglob.h | 16 +++++++++++++++-
 fs/cifs/dir.c      |  3 +++
 fs/cifs/file.c     |  4 ++++
 fs/locks.c         |  8 ++++++++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index cd4bbf3..7e876b9 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -465,7 +465,7 @@ struct smb_vol {
 			 CIFS_MOUNT_CIFS_BACKUPUID | CIFS_MOUNT_CIFS_BACKUPGID)
 
 #define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
-		      MS_NODEV | MS_SYNCHRONOUS)
+		      MS_NODEV | MS_SYNCHRONOUS | MS_SHARELOCK)
 
 struct cifs_mnt_data {
 	struct cifs_sb_info *cifs_sb;
@@ -947,6 +947,20 @@ struct cifsFileInfo {
 	struct work_struct oplock_break; /* work for oplock breaks */
 };
 
+static inline int
+cifs_get_share_flags(unsigned int flags)
+{
+	int share_access = 0;
+
+	if (!(flags & O_DENYREAD))
+		share_access |= FILE_SHARE_READ;
+	if (!(flags & O_DENYWRITE))
+		share_access |= FILE_SHARE_WRITE;
+	if (!(flags & O_DENYDELETE))
+		share_access |= FILE_SHARE_DELETE;
+	return share_access;
+}
+
 struct cifs_io_parms {
 	__u16 netfid;
 #ifdef CONFIG_CIFS_SMB2
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 267b608..d4331de 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -294,6 +294,9 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
 	else
 		cFYI(1, "Create flag not set in create function");
 
+	if (IS_SHARELOCK(inode))
+		share_access = cifs_get_share_flags(oflags);
+
 	/*
 	 * BB add processing to set equivalent of mode - e.g. via CreateX with
 	 * ACLs
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0d524a7..9394b2b 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -210,6 +210,8 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
  *********************************************************************/
 
 	disposition = cifs_get_disposition(f_flags);
+	if (IS_SHARELOCK(inode))
+		share_access = cifs_get_share_flags(f_flags);
 
 	/* BB pass O_SYNC flag through on file attributes .. BB */
 
@@ -645,6 +647,8 @@ cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 	}
 
 	desired_access = cifs_convert_flags(cfile->f_flags);
+	if (IS_SHARELOCK(inode))
+		share_access = cifs_get_share_flags(cfile->f_flags);
 
 	if (backup_cred(cifs_sb))
 		create_options |= CREATE_OPEN_BACKUP_INTENT;
diff --git a/fs/locks.c b/fs/locks.c
index 1eccc75..2184ddd 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -846,10 +846,18 @@ deny_lock_file(struct file *filp)
 {
 	struct file_lock *lock;
 	int error = 0;
+	const char *fsname = filp->f_path.dentry->d_inode->i_sb->s_type->name;
 
 	if (!IS_SHARELOCK(filp->f_path.dentry->d_inode))
 		return error;
 
+	/*
+	 * Don't set a lock on CIFS file systems because they can process it
+	 * themselves.
+	 */
+	if (!strncmp(fsname, "cifs", 4))
+		return error;
+
 	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
 	if (error)
 		return error;
-- 
1.8.1.5

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