#include <linux/string.h>
#include <linux/mm.h>
#include <linux/file.h>
+#include <linux/fdtable.h>
#include <linux/quotaops.h>
#include <linux/fsnotify.h>
#include <linux/module.h>
if (!S_ISREG(inode->i_mode))
goto dput_and_out;
- error = vfs_permission(&nd, MAY_WRITE);
+ error = mnt_want_write(nd.path.mnt);
if (error)
goto dput_and_out;
- error = -EROFS;
- if (IS_RDONLY(inode))
- goto dput_and_out;
+ error = vfs_permission(&nd, MAY_WRITE);
+ if (error)
+ goto mnt_drop_write_and_out;
error = -EPERM;
if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
- goto dput_and_out;
+ goto mnt_drop_write_and_out;
error = get_write_access(inode);
if (error)
- goto dput_and_out;
+ goto mnt_drop_write_and_out;
/*
* Make sure that there are no leases. get_write_access() protects
put_write_and_out:
put_write_access(inode);
+mnt_drop_write_and_out:
+ mnt_drop_write(nd.path.mnt);
dput_and_out:
path_put(&nd.path);
out:
if(res || !(mode & S_IWOTH) ||
special_file(nd.path.dentry->d_inode->i_mode))
goto out_path_release;
-
- if(IS_RDONLY(nd.path.dentry->d_inode))
+ /*
+ * This is a rare case where using __mnt_is_readonly()
+ * is OK without a mnt_want/drop_write() pair. Since
+ * no actual write to the fs is performed here, we do
+ * not need to telegraph to that to anyone.
+ *
+ * By doing this, we accept that this access is
+ * inherently racy and know that the fs may change
+ * state before we even see this result.
+ */
+ if (__mnt_is_readonly(nd.path.mnt))
res = -EROFS;
out_path_release:
error = __get_file_write_access(inode, mnt);
if (error)
goto cleanup_file;
+ if (!special_file(inode->i_mode))
+ file_take_write(f);
}
f->f_mapping = inode->i_mapping;
if (f->f_flags & O_DIRECT) {
if (!f->f_mapping->a_ops ||
((!f->f_mapping->a_ops->direct_IO) &&
- (!f->f_mapping->a_ops->get_xip_page))) {
+ (!f->f_mapping->a_ops->get_xip_mem))) {
fput(f);
f = ERR_PTR(-EINVAL);
}
fops_put(f->f_op);
if (f->f_mode & FMODE_WRITE) {
put_write_access(inode);
- if (!special_file(inode->i_mode))
+ if (!special_file(inode->i_mode)) {
+ /*
+ * We don't consider this a real
+ * mnt_want/drop_write() pair
+ * because it all happenend right
+ * here, so just reset the state.
+ */
+ file_reset_write(f);
mnt_drop_write(mnt);
+ }
}
file_kill(f);
f->f_path.dentry = NULL;