[PATCH v5 3/7] CIFS: Add O_DENY* open flags support

[Pavel Shilovsky]

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

Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
---
 fs/cifs/cifsfs.c   |  2 +-
 fs/cifs/cifsglob.h | 16 +++++++++++++++-
 fs/cifs/dir.c      |  3 +++
 fs/cifs/file.c     |  4 ++++
 fs/locks.c         |  7 ++++++-
 include/linux/fs.h |  1 +
 6 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index e328339..469dffb 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -769,7 +769,7 @@ struct file_system_type cifs_fs_type = {
 	.name = "cifs",
 	.mount = cifs_do_mount,
 	.kill_sb = cifs_kill_sb,
-	/*  .fs_flags */
+	.fs_flags = FS_DOES_SHARELOCK,
 };
 const struct inode_operations cifs_dir_inode_ops = {
 	.create = cifs_create,
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..52c9ea1 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -846,8 +846,13 @@ deny_lock_file(struct file *filp)
 {
 	struct file_lock *lock;
 	int error = 0;
+	struct inode *inode = filp->f_path.dentry->d_inode;
 
-	if (!IS_SHARELOCK(filp->f_path.dentry->d_inode))
+	if (!IS_SHARELOCK(inode))
+		return error;
+
+	/* Don't set a lock on file systems that do it internally */
+	if (inode->i_sb->s_type->fs_flags & FS_DOES_SHARELOCK)
 		return error;
 
 	error = flock_make_lock(filp, &lock, deny_flags_to_cmd(filp->f_flags));
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 073e31a..8a4232e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1816,6 +1816,7 @@ struct file_system_type {
 #define FS_USERNS_DEV_MOUNT	16 /* A userns mount does not imply MNT_NODEV */
 #define FS_REVAL_DOT		16384	/* Check the paths ".", ".." for staleness */
 #define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move() during rename() internally. */
+#define FS_DOES_SHARELOCK	65536	/* FS does sharelocks internally */
 	struct dentry *(*mount) (struct file_system_type *, int,
 		       const char *, void *);
 	void (*kill_sb) (struct super_block *);
-- 
1.8.1.5

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