[PATCH v2 05/17] locks: generic_delete_lease doesn't need a file_lock at all

Jeff Layton
2014-09-04T12:39:03Z

Ensure that it's OK to pass in a NULL file_lock double pointer on
a F_UNLCK request and convert the vfs_setlease F_UNLCK callers to
do just that.

Finally, turn the BUG_ON in generic_setlease into a WARN_ON_ONCE
with an error return. That's a problem we can handle without
crashing the box if it occurs.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/locks.c | 34 ++++++++++++++--------------------
fs/nfsd/nfs4state.c | 2 +-
include/trace/events/filelock.h | 14 +++++++-------
3 files changed, 22 insertions(+), 28 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 4031324e6cca..1289b74fffbf 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1637,22 +1637,23 @@ out:
return error;
}

-static int generic_delete_lease(struct file *filp, struct file_lock **flp)
+static int generic_delete_lease(struct file *filp)
{
+ int error = -EAGAIN;
struct file_lock *fl, **before;
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;

- trace_generic_delete_lease(inode, *flp);
-
for (before = &inode->i_flock;
((fl = *before) != NULL) && IS_LEASE(fl);
before = &fl->fl_next) {
- if (fl->fl_file != filp)
- continue;
- return (*flp)->fl_lmops->lm_change(before, F_UNLCK);
+ if (fl->fl_file == filp)
+ break;
}
- return -EAGAIN;
+ trace_generic_delete_lease(inode, fl);
+ if (fl)
+ error = fl->fl_lmops->lm_change(before, F_UNLCK);
+ return error;
}

/**
@@ -1682,13 +1683,15 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)

time_out_leases(inode);

- BUG_ON(!(*flp)->fl_lmops->lm_break);
-
switch (arg) {
case F_UNLCK:
- return generic_delete_lease(filp, flp);
+ return generic_delete_lease(filp);
case F_RDLCK:
case F_WRLCK:
+ if (!(*flp)->fl_lmops->lm_break) {
+ WARN_ON_ONCE(1);
+ return -ENOLCK;
+ }
return generic_add_lease(filp, arg, flp);
default:
return -EINVAL;
@@ -1744,15 +1747,6 @@ int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
}
EXPORT_SYMBOL_GPL(vfs_setlease);

-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, *ret;
@@ -1809,7 +1803,7 @@ out_unlock:
int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
{
if (arg == F_UNLCK)
- return do_fcntl_delete_lease(filp);
+ return vfs_setlease(filp, F_UNLCK, NULL);
return do_fcntl_add_lease(fd, filp, arg);
}

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 29fac18d9102..0cd252916e1a 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -683,7 +683,7 @@ static void nfs4_put_deleg_lease(struct nfs4_file *fp)
if (!fp->fi_lease)
return;
if (atomic_dec_and_test(&fp->fi_delegees)) {
- vfs_setlease(fp->fi_deleg_file, F_UNLCK, &fp->fi_lease);
+ vfs_setlease(fp->fi_deleg_file, F_UNLCK, NULL);
fp->fi_lease = NULL;
fput(fp->fi_deleg_file);
fp->fi_deleg_file = NULL;
diff --git a/include/trace/events/filelock.h b/include/trace/events/filelock.h
index 59d11c22f076..a0d008070962 100644
--- a/include/trace/events/filelock.h
+++ b/include/trace/events/filelock.h
@@ -53,15 +53,15 @@ DECLARE_EVENT_CLASS(filelock_lease,
),

TP_fast_assign(
- __entry->fl = fl;
+ __entry->fl = fl ? fl : NULL;
__entry->s_dev = inode->i_sb->s_dev;
__entry->i_ino = inode->i_ino;
- __entry->fl_next = fl->fl_next;
- __entry->fl_owner = fl->fl_owner;
- __entry->fl_flags = fl->fl_flags;
- __entry->fl_type = fl->fl_type;
- __entry->fl_break_time = fl->fl_break_time;
- __entry->fl_downgrade_time = fl->fl_downgrade_time;
+ __entry->fl_next = fl ? fl->fl_next : NULL;
+ __entry->fl_owner = fl ? fl->fl_owner : NULL;
+ __entry->fl_flags = fl ? fl->fl_flags : 0;
+ __entry->fl_type = fl ? fl->fl_type : 0;
+ __entry->fl_break_time = fl ? fl->fl_break_time : 0;
+ __entry->fl_downgrade_time = fl ? fl->fl_downgrade_time : 0;
),

TP_printk("fl=0x%p dev=0x%x:0x%x ino=0x%lx fl_next=0x%p fl_owner=0x%p fl_flags=%s fl_type=%s fl_break_time=%lu fl_downgrade_time=%lu",
--
1.9.3