[PATCH RFC v2 14/28] filelock: rework the __break_lease API to use flags

[Jeff Layton <jlayton@kernel.org>]

Declare a set of LEASE_BREAK_* flags that can be used to control how
lease breaks work instead of requiring a type and an openmode.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/locks.c               | 30 +++++++++++++++++-----------
 include/linux/filelock.h | 52 +++++++++++++++++++++++++++++++++++-------------
 2 files changed, 56 insertions(+), 26 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 82a1b528dc9dae8c1f3a81084072e649d481e8f1..6e46176d1e00962904f03c151500e593f410e4c6 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1529,29 +1529,35 @@ any_leases_conflict(struct inode *inode, struct file_lease *breaker)
 /**
  *	__break_lease	-	revoke all outstanding leases on file
  *	@inode: the inode of the file to return
- *	@mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
- *	    break all leases
- *	@type: FL_LEASE: break leases and delegations; FL_DELEG: break
- *	    only delegations
+ *	@flags: LEASE_BREAK_* flags
  *
  *	break_lease (inlined for speed) has checked there already is at least
  *	some kind of lock (maybe a lease) on this file.  Leases are broken on
- *	a call to open() or truncate().  This function can sleep unless you
- *	specified %O_NONBLOCK to your open().
+ *	a call to open() or truncate().  This function can block waiting for the
+ *	lease break unless you specify LEASE_BREAK_NONBLOCK.
  */
-int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
+int __break_lease(struct inode *inode, unsigned int flags)
 {
-	int error = 0;
-	struct file_lock_context *ctx;
 	struct file_lease *new_fl, *fl, *tmp;
+	struct file_lock_context *ctx;
 	unsigned long break_time;
-	int want_write = (mode & O_ACCMODE) != O_RDONLY;
 	LIST_HEAD(dispose);
+	bool want_write = !(flags & LEASE_BREAK_OPEN_RDONLY);
+	int error = 0;
+
 
 	new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
 	if (IS_ERR(new_fl))
 		return PTR_ERR(new_fl);
-	new_fl->c.flc_flags = type;
+
+	if (flags & LEASE_BREAK_LEASE)
+		new_fl->c.flc_flags = FL_LEASE;
+	else if (flags & LEASE_BREAK_DELEG)
+		new_fl->c.flc_flags = FL_DELEG;
+	else if (flags & LEASE_BREAK_LAYOUT)
+		new_fl->c.flc_flags = FL_LAYOUT;
+	else
+		return -EINVAL;
 
 	/* typically we will check that ctx is non-NULL before calling */
 	ctx = locks_inode_context(inode);
@@ -1596,7 +1602,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
 	if (list_empty(&ctx->flc_lease))
 		goto out;
 
-	if (mode & O_NONBLOCK) {
+	if (flags & LEASE_BREAK_NONBLOCK) {
 		trace_break_lease_noblock(inode, new_fl);
 		error = -EWOULDBLOCK;
 		goto out;
diff --git a/include/linux/filelock.h b/include/linux/filelock.h
index 60c76c8fb4dfdcaaa2cfa3f41f0f26ffcb3db29f..0fe368060781d0b22f735c2cfb8d8c1a6a238290 100644
--- a/include/linux/filelock.h
+++ b/include/linux/filelock.h
@@ -221,7 +221,14 @@ int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl);
 void locks_init_lease(struct file_lease *);
 void locks_free_lease(struct file_lease *fl);
 struct file_lease *locks_alloc_lease(void);
-int __break_lease(struct inode *inode, unsigned int flags, unsigned int type);
+
+#define LEASE_BREAK_LEASE		BIT(0)	// break leases and delegations
+#define LEASE_BREAK_DELEG		BIT(1)	// break delegations only
+#define LEASE_BREAK_LAYOUT		BIT(2)	// break layouts only
+#define LEASE_BREAK_NONBLOCK		BIT(3)	// non-blocking break
+#define LEASE_BREAK_OPEN_RDONLY		BIT(4)	// readonly open event
+
+int __break_lease(struct inode *inode, unsigned int flags);
 void lease_get_mtime(struct inode *, struct timespec64 *time);
 int generic_setlease(struct file *, int, struct file_lease **, void **priv);
 int kernel_setlease(struct file *, int, struct file_lease **, void **);
@@ -376,7 +383,7 @@ static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *f
 	return -ENOLCK;
 }
 
-static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
+static inline int __break_lease(struct inode *inode, unsigned int flags)
 {
 	return 0;
 }
@@ -437,6 +444,17 @@ static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
 }
 
 #ifdef CONFIG_FILE_LOCKING
+static inline unsigned int openmode_to_lease_flags(unsigned int mode)
+{
+	unsigned int flags = 0;
+
+	if ((mode & O_ACCMODE) == O_RDONLY)
+		flags |= LEASE_BREAK_OPEN_RDONLY;
+	if (mode & O_NONBLOCK)
+		flags |= LEASE_BREAK_NONBLOCK;
+	return flags;
+}
+
 static inline int break_lease(struct inode *inode, unsigned int mode)
 {
 	struct file_lock_context *flctx;
@@ -452,11 +470,11 @@ static inline int break_lease(struct inode *inode, unsigned int mode)
 		return 0;
 	smp_mb();
 	if (!list_empty_careful(&flctx->flc_lease))
-		return __break_lease(inode, mode, FL_LEASE);
+		return __break_lease(inode, LEASE_BREAK_LEASE | openmode_to_lease_flags(mode));
 	return 0;
 }
 
-static inline int break_deleg(struct inode *inode, unsigned int mode)
+static inline int break_deleg(struct inode *inode, unsigned int flags)
 {
 	struct file_lock_context *flctx;
 
@@ -470,8 +488,10 @@ static inline int break_deleg(struct inode *inode, unsigned int mode)
 	if (!flctx)
 		return 0;
 	smp_mb();
-	if (!list_empty_careful(&flctx->flc_lease))
-		return __break_lease(inode, mode, FL_DELEG);
+	if (!list_empty_careful(&flctx->flc_lease)) {
+		flags |= LEASE_BREAK_DELEG;
+		return __break_lease(inode, flags);
+	}
 	return 0;
 }
 
@@ -479,7 +499,7 @@ static inline int try_break_deleg(struct inode *inode, struct inode **delegated_
 {
 	int ret;
 
-	ret = break_deleg(inode, O_WRONLY|O_NONBLOCK);
+	ret = break_deleg(inode, LEASE_BREAK_NONBLOCK);
 	if (ret == -EWOULDBLOCK && delegated_inode) {
 		*delegated_inode = inode;
 		ihold(inode);
@@ -491,7 +511,7 @@ static inline int break_deleg_wait(struct inode **delegated_inode)
 {
 	int ret;
 
-	ret = break_deleg(*delegated_inode, O_WRONLY);
+	ret = break_deleg(*delegated_inode, 0);
 	iput(*delegated_inode);
 	*delegated_inode = NULL;
 	return ret;
@@ -500,20 +520,24 @@ static inline int break_deleg_wait(struct inode **delegated_inode)
 static inline int break_layout(struct inode *inode, bool wait)
 {
 	smp_mb();
-	if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
-		return __break_lease(inode,
-				wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
-				FL_LAYOUT);
+	if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease)) {
+		unsigned int flags = LEASE_BREAK_LAYOUT;
+
+		if (!wait)
+			flags |= LEASE_BREAK_NONBLOCK;
+
+		return __break_lease(inode, flags);
+	}
 	return 0;
 }
 
 #else /* !CONFIG_FILE_LOCKING */
-static inline int break_lease(struct inode *inode, unsigned int mode)
+static inline int break_lease(struct inode *inode, bool wait)
 {
 	return 0;
 }
 
-static inline int break_deleg(struct inode *inode, unsigned int mode)
+static inline int break_deleg(struct inode *inode, unsigned int flags)
 {
 	return 0;
 }

-- 
2.49.0