[PATCH v2 11/17] locks: move freeing of leases outside of i_lock

Jeff Layton
2014-09-04T12:39:14Z

There was only one place where we still could free a file_lock while
holding the i_lock -- lease_modify. Add a new list_head argument to the
lm_change operation, pass in a private list when calling it, and fix
those callers to dispose of the list once the lock has been dropped.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
---
fs/locks.c | 34 ++++++++++++++++++++++------------
fs/nfsd/nfs4state.c | 6 +++---
include/linux/fs.h | 7 ++++---
3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 5bc61091263f..dc2e9e18f32d 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1292,7 +1292,7 @@ static void lease_clear_pending(struct file_lock *fl, int arg)
}

/* We already had a lease on this file; just change its type */
-int lease_modify(struct file_lock **before, int arg)
+int lease_modify(struct file_lock **before, int arg, struct list_head *dispose)
{
struct file_lock *fl = *before;
int error = assign_type(fl, arg);
@@ -1311,7 +1311,7 @@ int lease_modify(struct file_lock **before, int arg)
printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
fl->fl_fasync = NULL;
}
- locks_delete_lock(before, NULL);
+ locks_delete_lock(before, dispose);
}
return 0;
}
@@ -1325,7 +1325,7 @@ static bool past_time(unsigned long then)
return time_after(jiffies, then);
}

-static void time_out_leases(struct inode *inode)
+static void time_out_leases(struct inode *inode, struct list_head *dispose)
{
struct file_lock **before;
struct file_lock *fl;
@@ -1336,9 +1336,9 @@ static void time_out_leases(struct inode *inode)
while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) {
trace_time_out_leases(inode, fl);
if (past_time(fl->fl_downgrade_time))
- lease_modify(before, F_RDLCK);
+ lease_modify(before, F_RDLCK, dispose);
if (past_time(fl->fl_break_time))
- lease_modify(before, F_UNLCK);
+ lease_modify(before, F_UNLCK, dispose);
if (fl == *before) /* lease_modify may have freed fl */
before = &fl->fl_next;
}
@@ -1373,6 +1373,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
int i_have_this_lease = 0;
bool lease_conflict = false;
int want_write = (mode & O_ACCMODE) != O_RDONLY;
+ LIST_HEAD(dispose);

new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
if (IS_ERR(new_fl))
@@ -1381,7 +1382,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)

spin_lock(&inode->i_lock);

- time_out_leases(inode);
+ time_out_leases(inode, &dispose);

flock = inode->i_flock;
if ((flock == NULL) || !IS_LEASE(flock))
@@ -1436,6 +1437,7 @@ restart:
locks_insert_block(flock, new_fl);
trace_break_lease_block(inode, new_fl);
spin_unlock(&inode->i_lock);
+ locks_dispose_list(&dispose);
error = wait_event_interruptible_timeout(new_fl->fl_wait,
!new_fl->fl_next, break_time);
spin_lock(&inode->i_lock);
@@ -1443,7 +1445,7 @@ restart:
locks_delete_block(new_fl);
if (error >= 0) {
if (error == 0)
- time_out_leases(inode);
+ time_out_leases(inode, &dispose);
/*
* Wait for the next conflicting lease that has not been
* broken yet
@@ -1458,6 +1460,7 @@ restart:

out:
spin_unlock(&inode->i_lock);
+ locks_dispose_list(&dispose);
locks_free_lock(new_fl);
return error;
}
@@ -1522,9 +1525,10 @@ int fcntl_getlease(struct file *filp)
struct file_lock *fl;
struct inode *inode = file_inode(filp);
int type = F_UNLCK;
+ LIST_HEAD(dispose);

spin_lock(&inode->i_lock);
- time_out_leases(file_inode(filp));
+ time_out_leases(file_inode(filp), &dispose);
for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl);
fl = fl->fl_next) {
if (fl->fl_file == filp) {
@@ -1533,6 +1537,7 @@ int fcntl_getlease(struct file *filp)
}
}
spin_unlock(&inode->i_lock);
+ locks_dispose_list(&dispose);
return type;
}

@@ -1570,6 +1575,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
struct inode *inode = dentry->d_inode;
bool is_deleg = (*flp)->fl_flags & FL_DELEG;
int error;
+ LIST_HEAD(dispose);

lease = *flp;
trace_generic_add_lease(inode, lease);
@@ -1593,7 +1599,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
}

spin_lock(&inode->i_lock);
- time_out_leases(inode);
+ time_out_leases(inode, &dispose);
error = check_conflicting_open(dentry, arg);
if (error)
goto out;
@@ -1630,7 +1636,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr

if (my_before != NULL) {
lease = *my_before;
- error = lease->fl_lmops->lm_change(my_before, arg);
+ error = lease->fl_lmops->lm_change(my_before, arg, &dispose);
if (error)
goto out;
goto out_setup;
@@ -1660,6 +1666,7 @@ out_setup:
lease->fl_lmops->lm_setup(lease, priv);
out:
spin_unlock(&inode->i_lock);
+ locks_dispose_list(&dispose);
if (is_deleg)
mutex_unlock(&inode->i_mutex);
if (!error && !my_before)
@@ -1676,8 +1683,10 @@ static int generic_delete_lease(struct file *filp)
struct file_lock *fl, **before;
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
+ LIST_HEAD(dispose);

spin_lock(&inode->i_lock);
+ time_out_leases(inode, &dispose);
for (before = &inode->i_flock;
((fl = *before) != NULL) && IS_LEASE(fl);
before = &fl->fl_next) {
@@ -1686,8 +1695,9 @@ static int generic_delete_lease(struct file *filp)
}
trace_generic_delete_lease(inode, fl);
if (fl)
- error = fl->fl_lmops->lm_change(before, F_UNLCK);
+ error = fl->fl_lmops->lm_change(before, F_UNLCK, &dispose);
spin_unlock(&inode->i_lock);
+ locks_dispose_list(&dispose);
return error;
}

@@ -2375,7 +2385,7 @@ void locks_remove_file(struct file *filp)
while ((fl = *before) != NULL) {
if (fl->fl_file == filp) {
if (IS_LEASE(fl)) {
- lease_modify(before, F_UNLCK);
+ lease_modify(before, F_UNLCK, &dispose);
continue;
}

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 86eebf13b3d0..44e04d6be676 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3423,11 +3423,11 @@ static void nfsd_break_deleg_cb(struct file_lock *fl)
spin_unlock(&fp->fi_lock);
}

-static
-int nfsd_change_deleg_cb(struct file_lock **onlist, int arg)
+static int
+nfsd_change_deleg_cb(struct file_lock **onlist, int arg, struct list_head *dispose)
{
if (arg & F_UNLCK)
- return lease_modify(onlist, arg);
+ return lease_modify(onlist, arg, dispose);
else
return -EAGAIN;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9a6d56154dd5..f419f718e447 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -873,7 +873,7 @@ struct lock_manager_operations {
void (*lm_notify)(struct file_lock *); /* unblock callback */
int (*lm_grant)(struct file_lock *, int);
void (*lm_break)(struct file_lock *);
- int (*lm_change)(struct file_lock **, int);
+ int (*lm_change)(struct file_lock **, int, struct list_head *);
void (*lm_setup)(struct file_lock *, void **);
};

@@ -985,7 +985,7 @@ extern int __break_lease(struct inode *inode, unsigned int flags, unsigned int t
extern void lease_get_mtime(struct inode *, struct timespec *time);
extern int generic_setlease(struct file *, long, struct file_lock **, void **priv);
extern int vfs_setlease(struct file *, long, struct file_lock **, void **);
-extern int lease_modify(struct file_lock **, int);
+extern int lease_modify(struct file_lock **, int, struct list_head *);
#else /* !CONFIG_FILE_LOCKING */
static inline int fcntl_getlk(struct file *file, unsigned int cmd,
struct flock __user *user)
@@ -1112,7 +1112,8 @@ static inline int vfs_setlease(struct file *filp, long arg,
return -EINVAL;
}

-static inline int lease_modify(struct file_lock **before, int arg)
+static inline int lease_modify(struct file_lock **before, int arg,
+ struct list_head *dispose)
{
return -EINVAL;
}
--
1.9.3