dquot: move dquot initialization responsibility into the filesystem

Currently various places in the VFS call vfs_dq_init directly.  This means
we tie the quota code into the VFS.  Get rid of that and make the
filesystem responsible for the initialization.   For most metadata operations
this is a straight forward move into the methods, but for truncate and
open it's a bit more complicated.

For truncate we currently only call vfs_dq_init for the sys_truncate case
because open already takes care of it for ftruncate and open(O_TRUNC) - the
new code causes an additional vfs_dq_init for those which is harmless.

For open the initialization is moved from do_filp_open into the open method,
which means it happens slightly earlier now, and only for regular files.
The latter is fine because we don't need to initialize it for operations
on special files, and we already do it as part of the namespace operations
for directories.

Add a dquot_file_open helper that filesystems that support generic quotas
can use to fill in ->open.

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jan Kara <[email protected]>

fs/ufs/file.c

@@ -40,7 +40,7 @@ const struct file_operations ufs_file_operations = {
 	.write		= do_sync_write,
 	.aio_write	= generic_file_aio_write,
 	.mmap		= generic_file_mmap,
-	.open           = generic_file_open,
+	.open           = dquot_file_open,
 	.fsync		= simple_fsync,
 	.splice_read	= generic_file_splice_read,
 };

fs/ufs/inode.c

@@ -36,6 +36,7 @@
 #include <linux/mm.h>
 #include <linux/smp_lock.h>
 #include <linux/buffer_head.h>
+#include <linux/quotaops.h>
 
 #include "ufs_fs.h"
 #include "ufs.h"
@@ -908,6 +909,9 @@ void ufs_delete_inode (struct inode * inode)
 {
 	loff_t old_i_size;
 
+	if (!is_bad_inode(inode))
+		vfs_dq_init(inode);
+
 	truncate_inode_pages(&inode->i_data, 0);
 	if (is_bad_inode(inode))
 		goto no_delete;

fs/ufs/namei.c

@@ -30,6 +30,7 @@
 #include <linux/time.h>
 #include <linux/fs.h>
 #include <linux/smp_lock.h>
+#include <linux/quotaops.h>
 
 #include "ufs_fs.h"
 #include "ufs.h"
@@ -84,6 +85,9 @@ static int ufs_create (struct inode * dir, struct dentry * dentry, int mode,
 	int err;
 
 	UFSD("BEGIN\n");
+
+	vfs_dq_init(dir);
+
 	inode = ufs_new_inode(dir, mode);
 	err = PTR_ERR(inode);
 
@@ -107,6 +111,9 @@ static int ufs_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t
 
 	if (!old_valid_dev(rdev))
 		return -EINVAL;
+
+	vfs_dq_init(dir);
+
 	inode = ufs_new_inode(dir, mode);
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
@@ -131,6 +138,8 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 	if (l > sb->s_blocksize)
 		goto out_notlocked;
 
+	vfs_dq_init(dir);
+
 	lock_kernel();
 	inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 	err = PTR_ERR(inode);
@@ -176,6 +185,8 @@ static int ufs_link (struct dentry * old_dentry, struct inode * dir,
 		return -EMLINK;
 	}
 
+	vfs_dq_init(dir);
+
 	inode->i_ctime = CURRENT_TIME_SEC;
 	inode_inc_link_count(inode);
 	atomic_inc(&inode->i_count);
@@ -193,6 +204,8 @@ static int ufs_mkdir(struct inode * dir, struct dentry * dentry, int mode)
 	if (dir->i_nlink >= UFS_LINK_MAX)
 		goto out;
 
+	vfs_dq_init(dir);
+
 	lock_kernel();
 	inode_inc_link_count(dir);
 
@@ -237,6 +250,8 @@ static int ufs_unlink(struct inode *dir, struct dentry *dentry)
 	struct page *page;
 	int err = -ENOENT;
 
+	vfs_dq_init(dir);
+
 	de = ufs_find_entry(dir, &dentry->d_name, &page);
 	if (!de)
 		goto out;
@@ -281,6 +296,9 @@ static int ufs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	struct ufs_dir_entry *old_de;
 	int err = -ENOENT;
 
+	vfs_dq_init(old_dir);
+	vfs_dq_init(new_dir);
+
 	old_de = ufs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 	if (!old_de)
 		goto out;

fs/ufs/truncate.c

@@ -527,6 +527,9 @@ static int ufs_setattr(struct dentry *dentry, struct iattr *attr)
 	if (ia_valid & ATTR_SIZE &&
 	    attr->ia_size != i_size_read(inode)) {
 		loff_t old_i_size = inode->i_size;
+
+		vfs_dq_init(inode);
+
 		error = vmtruncate(inode, attr->ia_size);
 		if (error)
 			return error;