From: Trond Myklebust <trond.myklebust@fys.uio.no>
VFS: More extensive fix to locking code. Add file_lock_operations to deal
with copy/release of private data in the file_lock->fl_u field. Add
filesystem hooks for steal_locks(): changing the lockowner is hardly a
supported concept in most file locking protocols.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/locks.c | 40 ++++++++++++++++++++++++++++++----------
25-akpm/include/linux/fs.h | 8 ++++++++
2 files changed, 38 insertions(+), 10 deletions(-)
diff -puN fs/locks.c~posix-locking-fix-to-locking-code fs/locks.c
--- 25/fs/locks.c~posix-locking-fix-to-locking-code 2004-08-07 19:27:50.954290696 -0700
+++ 25-akpm/fs/locks.c 2004-08-07 19:27:50.961289632 -0700
@@ -167,6 +167,11 @@ static inline void locks_free_lock(struc
if (!list_empty(&fl->fl_link))
panic("Attempting to free lock on active lock list");
+ if (fl->fl_ops && fl->fl_ops->fl_release_private) {
+ fl->fl_ops->fl_release_private(fl);
+ fl->fl_ops = NULL;
+ }
+
kmem_cache_free(filelock_cache, fl);
}
@@ -186,6 +191,7 @@ void locks_init_lock(struct file_lock *f
fl->fl_notify = NULL;
fl->fl_insert = NULL;
fl->fl_remove = NULL;
+ fl->fl_ops = NULL;
}
EXPORT_SYMBOL(locks_init_lock);
@@ -220,7 +226,9 @@ void locks_copy_lock(struct file_lock *n
new->fl_notify = fl->fl_notify;
new->fl_insert = fl->fl_insert;
new->fl_remove = fl->fl_remove;
- new->fl_u = fl->fl_u;
+ new->fl_ops = fl->fl_ops;
+ if (fl->fl_ops && fl->fl_ops->fl_copy_lock)
+ fl->fl_ops->fl_copy_lock(new, fl);
}
EXPORT_SYMBOL(locks_copy_lock);
@@ -324,6 +332,7 @@ static int flock_to_posix_lock(struct fi
fl->fl_notify = NULL;
fl->fl_insert = NULL;
fl->fl_remove = NULL;
+ fl->fl_ops = NULL;
return assign_type(fl, l->l_type);
}
@@ -364,6 +373,7 @@ static int flock64_to_posix_lock(struct
fl->fl_notify = NULL;
fl->fl_insert = NULL;
fl->fl_remove = NULL;
+ fl->fl_ops = NULL;
switch (l->l_type) {
case F_RDLCK:
@@ -400,6 +410,7 @@ static int lease_alloc(struct file *filp
fl->fl_notify = NULL;
fl->fl_insert = NULL;
fl->fl_remove = NULL;
+ fl->fl_ops = NULL;
*flp = fl;
return 0;
@@ -419,10 +430,9 @@ static inline int locks_overlap(struct f
static inline int
posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
{
- /* FIXME: Replace this sort of thing with struct file_lock_operations */
- if ((fl1->fl_type | fl2->fl_type) & FL_LOCKD)
- return fl1->fl_owner == fl2->fl_owner &&
- fl1->fl_pid == fl2->fl_pid;
+ if (fl1->fl_ops && fl1->fl_ops->fl_compare_owner)
+ return fl2->fl_ops == fl1->fl_ops &&
+ fl1->fl_ops->fl_compare_owner(fl1, fl2);
return fl1->fl_owner == fl2->fl_owner;
}
@@ -981,6 +991,8 @@ int locks_mandatory_area(int read_write,
break;
}
+ if (fl.fl_ops && fl.fl_ops->fl_release_private)
+ fl.fl_ops->fl_release_private(&fl);
return error;
}
@@ -1415,7 +1427,6 @@ int fcntl_getlk(struct file *filp, struc
error = -EFAULT;
if (!copy_to_user(l, &flock, sizeof(flock)))
error = 0;
-
out:
return error;
}
@@ -1665,6 +1676,7 @@ void locks_remove_posix(struct file *fil
lock.fl_owner = owner;
lock.fl_pid = current->tgid;
lock.fl_file = filp;
+ lock.fl_ops = NULL;
if (filp->f_op && filp->f_op->lock != NULL) {
filp->f_op->lock(filp, F_SETLK, &lock);
@@ -1684,6 +1696,8 @@ void locks_remove_posix(struct file *fil
before = &fl->fl_next;
}
unlock_kernel();
+ if (lock.fl_ops && lock.fl_ops->fl_release_private)
+ lock.fl_ops->fl_release_private(&lock);
}
EXPORT_SYMBOL(locks_remove_posix);
@@ -1978,12 +1992,18 @@ EXPORT_SYMBOL(lock_may_write);
static inline void __steal_locks(struct file *file, fl_owner_t from)
{
struct inode *inode = file->f_dentry->d_inode;
- struct file_lock *fl = inode->i_flock;
+ struct file_lock *fl;
- while (fl) {
- if (fl->fl_file == file && fl->fl_owner == from)
+restart:
+ for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
+ if (fl->fl_file == file && fl->fl_owner == from) {
+ if (fl->fl_ops && fl->fl_ops->fl_steal_locks) {
+ fl->fl_ops->fl_steal_locks(fl, from);
+ /* Some filesystems may just drop the lock */
+ goto restart;
+ }
fl->fl_owner = current->files;
- fl = fl->fl_next;
+ }
}
}
diff -puN include/linux/fs.h~posix-locking-fix-to-locking-code include/linux/fs.h
--- 25/include/linux/fs.h~posix-locking-fix-to-locking-code 2004-08-07 19:27:50.956290392 -0700
+++ 25-akpm/include/linux/fs.h 2004-08-07 19:27:50.963289328 -0700
@@ -628,6 +628,13 @@ extern void close_private_file(struct fi
*/
typedef struct files_struct *fl_owner_t;
+struct file_lock_operations {
+ int (*fl_compare_owner)(struct file_lock *, struct file_lock *);
+ void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
+ void (*fl_release_private)(struct file_lock *);
+ void (*fl_steal_locks)(struct file_lock *, fl_owner_t);
+};
+
/* that will die - we need it for nfs_lock_info */
#include <linux/nfs_fs_i.h>
@@ -651,6 +658,7 @@ struct file_lock {
struct fasync_struct * fl_fasync; /* for lease break notifications */
unsigned long fl_break_time; /* for nonblocking lease breaks */
+ struct file_lock_operations *fl_ops; /* Callbacks for lockmanagers */
union {
struct nfs_lock_info nfs_fl;
} fl_u;
_