*
* Initial implementation of mandatory locks. SunOS turned out to be
* a rotten model, so I implemented the "obvious" semantics.
- * See 'Documentation/mandatory.txt' for details.
+ * See 'Documentation/filesystems/mandatory-locking.txt' for details.
* Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
*
* Don't allow mandatory locks on mmap()'ed files. Added simple functions to
return type;
}
-/**
- * generic_setlease - sets a lease on an open file
- * @filp: file pointer
- * @arg: type of lease to obtain
- * @flp: input - file_lock to use, output - file_lock inserted
- *
- * The (input) flp->fl_lmops->lm_break function is required
- * by break_lease().
- *
- * Called with file_lock_lock held.
- */
-int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
+int generic_add_lease(struct file *filp, long arg, struct file_lock **flp)
{
struct file_lock *fl, **before, **my_before = NULL, *lease;
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
- int error, rdlease_count = 0, wrlease_count = 0;
+ int error;
lease = *flp;
- error = -EACCES;
- if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE))
- goto out;
- error = -EINVAL;
- if (!S_ISREG(inode->i_mode))
+ error = -EAGAIN;
+ if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
goto out;
- error = security_file_lock(filp, arg);
- if (error)
+ if ((arg == F_WRLCK)
+ && ((dentry->d_count > 1)
+ || (atomic_read(&inode->i_count) > 1)))
goto out;
- time_out_leases(inode);
-
- BUG_ON(!(*flp)->fl_lmops->lm_break);
-
- if (arg != F_UNLCK) {
- error = -EAGAIN;
- if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
- goto out;
- if ((arg == F_WRLCK)
- && ((dentry->d_count > 1)
- || (atomic_read(&inode->i_count) > 1)))
- goto out;
- }
-
/*
* At this point, we know that if there is an exclusive
* lease on this file, then we hold it on this filp
* then the file is not open by anyone (including us)
* except for this filp.
*/
+ error = -EAGAIN;
for (before = &inode->i_flock;
((fl = *before) != NULL) && IS_LEASE(fl);
before = &fl->fl_next) {
- if (fl->fl_file == filp)
+ if (fl->fl_file == filp) {
my_before = before;
- else if (fl->fl_flags & FL_UNLOCK_PENDING)
- /*
- * Someone is in the process of opening this
- * file for writing so we may not take an
- * exclusive lease on it.
- */
- wrlease_count++;
- else
- rdlease_count++;
+ continue;
+ }
+ /*
+ * No exclusive leases if someone else has a lease on
+ * this file:
+ */
+ if (arg == F_WRLCK)
+ goto out;
+ /*
+ * Modifying our existing lease is OK, but no getting a
+ * new lease if someone else is opening for write:
+ */
+ if (fl->fl_flags & FL_UNLOCK_PENDING)
+ goto out;
}
- error = -EAGAIN;
- if ((arg == F_RDLCK && (wrlease_count > 0)) ||
- (arg == F_WRLCK && ((rdlease_count + wrlease_count) > 0)))
- goto out;
-
if (my_before != NULL) {
error = lease->fl_lmops->lm_change(my_before, arg);
if (!error)
goto out;
}
- if (arg == F_UNLCK)
- goto out;
-
error = -EINVAL;
if (!leases_enable)
goto out;
out:
return error;
}
+
+int generic_delete_lease(struct file *filp, struct file_lock **flp)
+{
+ struct file_lock *fl, **before;
+ struct dentry *dentry = filp->f_path.dentry;
+ struct inode *inode = dentry->d_inode;
+
+ 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);
+ }
+ return -EAGAIN;
+}
+
+/**
+ * generic_setlease - sets a lease on an open file
+ * @filp: file pointer
+ * @arg: type of lease to obtain
+ * @flp: input - file_lock to use, output - file_lock inserted
+ *
+ * The (input) flp->fl_lmops->lm_break function is required
+ * by break_lease().
+ *
+ * Called with file_lock_lock held.
+ */
+int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
+{
+ struct dentry *dentry = filp->f_path.dentry;
+ struct inode *inode = dentry->d_inode;
+ int error;
+
+ if ((current_fsuid() != inode->i_uid) && !capable(CAP_LEASE))
+ return -EACCES;
+ if (!S_ISREG(inode->i_mode))
+ return -EINVAL;
+ error = security_file_lock(filp, arg);
+ if (error)
+ return error;
+
+ time_out_leases(inode);
+
+ BUG_ON(!(*flp)->fl_lmops->lm_break);
+
+ switch (arg) {
+ case F_UNLCK:
+ return generic_delete_lease(filp, flp);
+ case F_RDLCK:
+ case F_WRLCK:
+ return generic_add_lease(filp, arg, flp);
+ default:
+ BUG();
+ }
+}
EXPORT_SYMBOL(generic_setlease);
static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
git.openpandora.org / pandora-kernel.git / blobdiff