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authorJ. Bruce Fields <bfields@redhat.com>2010-10-30 17:31:13 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-30 18:08:14 -0700
commit0ceaf6c700f8245946a163e387add8675a0c302f (patch)
tree8f1657caff93050e416503b418c11c6e6b62b781 /fs/locks.c
parent0d07025effd3da8b9c74f18448823175f4c63a73 (diff)
downloadvexpress-lsk-0ceaf6c700f8245946a163e387add8675a0c302f.tar.gz
locks: prevent ENOMEM on lease unlock
Removing a lock shouldn't require any allocations; a failure due to ENOMEM leaves the caller with a choice between retrying or giving up and leaking an unused lease. Next we should split the other lease calls into add and delete cases. I wanted to start with just the bugfix. Signed-off-by: J. Bruce Fields <bfields@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/locks.c')
-rw-r--r--fs/locks.c43
1 files changed, 30 insertions, 13 deletions
diff --git a/fs/locks.c b/fs/locks.c
index 50ec15927aa..06c77734f58 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1441,7 +1441,8 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
return 0;
out:
- locks_free_lock(lease);
+ if (arg != F_UNLCK)
+ locks_free_lock(lease);
return error;
}
EXPORT_SYMBOL(generic_setlease);
@@ -1493,17 +1494,16 @@ int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
}
EXPORT_SYMBOL_GPL(vfs_setlease);
-/**
- * fcntl_setlease - sets a lease on an open file
- * @fd: open file descriptor
- * @filp: file pointer
- * @arg: type of lease to obtain
- *
- * Call this fcntl to establish a lease on the file.
- * Note that you also need to call %F_SETSIG to
- * receive a signal when the lease is broken.
- */
-int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
+static int do_fcntl_delete_lease(struct file *filp)
+{
+ struct file_lock fl, *flp = &fl;
+
+ lease_init(filp, F_UNLCK, flp);
+
+ return vfs_setlease(filp, F_UNLCK, &flp);
+}
+
+static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
{
struct file_lock *fl;
struct fasync_struct *new;
@@ -1521,7 +1521,7 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
}
lock_flocks();
error = __vfs_setlease(filp, arg, &fl);
- if (error || arg == F_UNLCK)
+ if (error)
goto out_unlock;
/*
@@ -1550,6 +1550,23 @@ out_unlock:
}
/**
+ * fcntl_setlease - sets a lease on an open file
+ * @fd: open file descriptor
+ * @filp: file pointer
+ * @arg: type of lease to obtain
+ *
+ * Call this fcntl to establish a lease on the file.
+ * Note that you also need to call %F_SETSIG to
+ * receive a signal when the lease is broken.
+ */
+int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
+{
+ if (arg == F_UNLCK)
+ return do_fcntl_delete_lease(filp);
+ return do_fcntl_add_lease(fd, filp, arg);
+}
+
+/**
* flock_lock_file_wait - Apply a FLOCK-style lock to a file
* @filp: The file to apply the lock to
* @fl: The lock to be applied