aufs: ioctl, mvdown 2/2, callers

Support for the options of MVDOWN feature, which allows to overwrite the
existing entry, and writing to the branch even if its permission is RO.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

fs/aufs/cpup.c

@@ -431,6 +431,7 @@ static int au_cp_regular(struct au_cp_generic *cpg)
 		aufs_bindex_t bindex;
 		unsigned int flags;
 		struct dentry *dentry;
+		int force_wr;
 		struct file *file;
 	} *f, file[] = {
 		{
@@ -440,6 +441,7 @@ static int au_cp_regular(struct au_cp_generic *cpg)
 		{
 			.bindex = cpg->bdst,
 			.flags = O_WRONLY | O_NOATIME | O_LARGEFILE,
+			.force_wr = !!au_ftest_cpup(cpg->flags, RWDST),
 		}
 	};
 	struct au_branch *br;
@@ -453,7 +455,7 @@ static int au_cp_regular(struct au_cp_generic *cpg)
 	for (i = 0; i < 2; i++, f++) {
 		f->dentry = au_h_dptr(cpg->dentry, f->bindex);
 		f->file = au_h_open(cpg->dentry, f->bindex, f->flags,
-				    /*file*/NULL);
+				    /*file*/NULL, f->force_wr);
 		if (IS_ERR(f->file)) {
 			err = PTR_ERR(f->file);
 			if (i == SRC)
@@ -736,19 +738,29 @@ int cpup_entry(struct au_cp_generic *cpg, struct dentry *dst_parent,
 static int au_do_ren_after_cpup(struct au_cp_generic *cpg, struct path *h_path)
 {
 	int err;
-	struct dentry *dentry, *h_dentry, *h_parent;
+	struct dentry *dentry, *h_dentry, *h_parent, *parent;
 	struct inode *h_dir;
 	aufs_bindex_t bdst;
 
 	dentry = cpg->dentry;
 	bdst = cpg->bdst;
 	h_dentry = au_h_dptr(dentry, bdst);
-	dget(h_dentry);
-	au_set_h_dptr(dentry, bdst, NULL);
-	err = au_lkup_neg(dentry, bdst, /*wh*/0);
-	if (!err)
-		h_path->dentry = dget(au_h_dptr(dentry, bdst));
-	au_set_h_dptr(dentry, bdst, h_dentry);
+	if (!au_ftest_cpup(cpg->flags, OVERWRITE)) {
+		dget(h_dentry);
+		au_set_h_dptr(dentry, bdst, NULL);
+		err = au_lkup_neg(dentry, bdst, /*wh*/0);
+		if (!err)
+			h_path->dentry = dget(au_h_dptr(dentry, bdst));
+		au_set_h_dptr(dentry, bdst, h_dentry);
+	} else {
+		err = 0;
+		parent = dget_parent(dentry);
+		h_parent = au_h_dptr(parent, bdst);
+		dput(parent);
+		h_path->dentry = vfsub_lkup_one(&dentry->d_name, h_parent);
+		if (IS_ERR(h_path->dentry))
+			err = PTR_ERR(h_path->dentry);
+	}
 	if (unlikely(err))
 		goto out;
 

fs/aufs/dir.c

@@ -219,7 +219,7 @@ static int reopen_dir(struct file *file)
 		if (h_file)
 			continue;
 
-		h_file = au_h_open(dentry, bindex, flags, file);
+		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
 		err = PTR_ERR(h_file);
 		if (IS_ERR(h_file))
 			goto out; /* close all? */
@@ -257,7 +257,7 @@ static int do_open_dir(struct file *file, int flags, struct file *h_file)
 		if (!h_dentry)
 			continue;
 
-		h_file = au_h_open(dentry, bindex, flags, file);
+		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
 		if (IS_ERR(h_file)) {
 			err = PTR_ERR(h_file);
 			break;
@@ -577,7 +577,7 @@ static int do_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
 
 	h_file = au_h_open(dentry, arg->bindex,
 			   O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_LARGEFILE,
-			   /*file*/NULL);
+			   /*file*/NULL, /*force_wr*/0);
 	err = PTR_ERR(h_file);
 	if (IS_ERR(h_file))
 		goto out;

fs/aufs/f_op.c

@@ -31,7 +31,7 @@ int au_do_open_nondir(struct file *file, int flags, struct file *h_file)
 	atomic_set(&finfo->fi_mmapped, 0);
 	bindex = au_dbtop(dentry);
 	if (!h_file)
-		h_file = au_h_open(dentry, bindex, flags, file);
+		h_file = au_h_open(dentry, bindex, flags, file, /*force_wr*/0);
 	else
 		get_file(h_file);
 	if (IS_ERR(h_file))

fs/aufs/file.c

@@ -23,7 +23,7 @@ unsigned int au_file_roflags(unsigned int flags)
 
 /* common functions to regular file and dir */
 struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
-		       struct file *file)
+		       struct file *file, int force_wr)
 {
 	struct file *h_file;
 	struct dentry *h_dentry;
@@ -55,8 +55,20 @@ struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
 		goto out;
 
 	/* drop flags for writing */
-	if (au_test_ro(sb, bindex, d_inode(dentry)))
+	if (au_test_ro(sb, bindex, d_inode(dentry))) {
+		if (force_wr && !(flags & O_WRONLY))
+			force_wr = 0;
 		flags = au_file_roflags(flags);
+		if (force_wr) {
+			h_file = ERR_PTR(-EROFS);
+			flags = au_file_roflags(flags);
+			if (unlikely(vfsub_native_ro(h_inode)
+				     || IS_APPEND(h_inode)))
+				goto out;
+			flags &= ~O_ACCMODE;
+			flags |= O_WRONLY;
+		}
+	}
 	flags &= ~O_CREAT;
 	au_lcnt_inc(&br->br_nfiles);
 	h_path.dentry = h_dentry;
@@ -169,7 +181,7 @@ int au_reopen_nondir(struct file *file)
 	/* AuDebugOn(au_fbtop(file) < btop); */
 
 	h_file = au_h_open(dentry, btop, vfsub_file_flags(file) & ~O_TRUNC,
-			   file);
+			   file, /*force_wr*/0);
 	err = PTR_ERR(h_file);
 	if (IS_ERR(h_file)) {
 		if (h_file_tmp) {

fs/aufs/file.h

@@ -61,7 +61,7 @@ struct au_finfo {
 extern const struct address_space_operations aufs_aop;
 unsigned int au_file_roflags(unsigned int flags);
 struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
-		       struct file *file);
+		       struct file *file, int force_wr);
 struct au_do_open_args {
 	int		aopen;
 	int		(*open)(struct file *file, int flags,

fs/aufs/ioctl.c

@@ -84,7 +84,8 @@ static int au_wbr_fd(struct path *path, struct aufs_wbr_fd __user *arg)
 	}
 	AuDbg("wbi %d\n", wbi);
 	if (wbi >= 0)
-		h_file = au_h_open(root, wbi, wbrfd.oflags, NULL);
+		h_file = au_h_open(root, wbi, wbrfd.oflags, NULL,
+				   /*force_wr*/0);
 
 out_unlock:
 	aufs_read_unlock(root, AuLock_IR);
@@ -143,6 +144,10 @@ long aufs_ioctl_nondir(struct file *file, unsigned int cmd, unsigned long arg)
 	long err;
 
 	switch (cmd) {
+	case AUFS_CTL_MVDOWN:
+		err = au_mvdown(file->f_path.dentry, (void __user *)arg);
+		break;
+
 	case AUFS_CTL_WBR_FD:
 		err = au_wbr_fd(&file->f_path, (void __user *)arg);
 		break;

include/uapi/linux/aufs_type.h

@@ -199,6 +199,7 @@ enum {
 
 	AuCtl_WBR_FD,	/* pathconf wrapper */
 	AuCtl_IBUSY,	/* busy inode */
+	AuCtl_MVDOWN,	/* move-down */
 	AuCtl_BR	/* info about branches */
 };
 
@@ -390,6 +391,8 @@ union aufs_brinfo {
 #define AUFS_CTL_WBR_FD		_IOW(AuCtlType, AuCtl_WBR_FD, \
 				     struct aufs_wbr_fd)
 #define AUFS_CTL_IBUSY		_IOWR(AuCtlType, AuCtl_IBUSY, struct aufs_ibusy)
+#define AUFS_CTL_MVDOWN		_IOWR(AuCtlType, AuCtl_MVDOWN, \
+				      struct aufs_mvdown)
 #define AUFS_CTL_BRINFO		_IOW(AuCtlType, AuCtl_BR, union aufs_brinfo)
 
 #endif /* __AUFS_TYPE_H__ */