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Subject[PATCH 03/10] Introduce has_locks_with_owner() helper
Date
From: Nathan Lynch <ntl@pobox.com>

Support for file locks is in the works, but until that is done
checkpoint needs to fail when an open file has locks.

Based on original "find_locks_with_owner" patch by Dave Hansen.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
[ntl: changed name and return type to clearly express semantics]
Signed-off-by: Nathan Lynch <ntl@pobox.com>
---
fs/locks.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/fs.h | 6 ++++++
2 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 8729347..961e17f 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2037,6 +2037,41 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)

EXPORT_SYMBOL(locks_remove_posix);

+bool has_locks_with_owner(struct file *filp, fl_owner_t owner)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ struct file_lock **inode_fl;
+ bool ret = false;
+
+ lock_flocks();
+ for_each_lock(inode, inode_fl) {
+ struct file_lock *fl = *inode_fl;
+ /*
+ * We could use posix_same_owner() along with a 'fake'
+ * file_lock. But, the fake file will never have the
+ * same fl_lmops as the fl that we are looking for and
+ * posix_same_owner() would just fall back to this
+ * check anyway.
+ */
+ if (IS_POSIX(fl)) {
+ if (fl->fl_owner == owner) {
+ ret = true;
+ break;
+ }
+ } else if (IS_FLOCK(fl) || IS_LEASE(fl)) {
+ if (fl->fl_file == filp) {
+ ret = true;
+ break;
+ }
+ } else {
+ WARN(1, "unknown file lock type, fl_flags: %x",
+ fl->fl_flags);
+ }
+ }
+ unlock_flocks();
+ return ret;
+}
+
/*
* This function is called on the last close of an open file.
*/
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 090f0ea..315ded4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1138,6 +1138,7 @@ extern void locks_remove_posix(struct file *, fl_owner_t);
extern void locks_remove_flock(struct file *);
extern void locks_release_private(struct file_lock *);
extern void posix_test_lock(struct file *, struct file_lock *);
+extern bool has_locks_with_owner(struct file *filp, fl_owner_t owner);
extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
extern int posix_lock_file_wait(struct file *, struct file_lock *);
extern int posix_unblock_lock(struct file *, struct file_lock *);
@@ -1208,6 +1209,11 @@ static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
return;
}

+static inline bool has_locks_with_owner(struct file *filp, fl_owner_t owner)
+{
+ return false;
+}
+
static inline void locks_remove_flock(struct file *filp)
{
return;
--
1.7.4


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