* [Ocfs2-devel] [PATCH 42/42] ocfs2: Add ioctl for reflink.
2009-09-21 22:27 [Ocfs2-devel] [PATCH 00/42] ocfs2: Add reflink file support. V5 TaoMa
@ 2009-09-21 14:29 ` Tao Ma
0 siblings, 0 replies; 2+ messages in thread
From: Tao Ma @ 2009-09-21 14:29 UTC (permalink / raw)
To: ocfs2-devel
The ioctl will take 3 parameters: old_path, new_path and
preserve and call vfs_reflink. It is useful when we backport
reflink features to old kernels.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
---
fs/ocfs2/ioctl.c | 14 ++++
fs/ocfs2/ocfs2_fs.h | 9 +++
fs/ocfs2/refcounttree.c | 166 +++++++++++++++++++++++++++++++++++++++++++++++
fs/ocfs2/refcounttree.h | 4 +
4 files changed, 193 insertions(+), 0 deletions(-)
diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 9fcd36d..a68d0e4 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -22,6 +22,7 @@
#include "ocfs2_fs.h"
#include "ioctl.h"
#include "resize.h"
+#include "refcounttree.h"
#include <linux/ext2_fs.h>
@@ -116,6 +117,9 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
int status;
struct ocfs2_space_resv sr;
struct ocfs2_new_group_input input;
+ struct reflink_arguments args;
+ const char *old_path, *new_path;
+ bool preserve;
switch (cmd) {
case OCFS2_IOC_GETFLAGS:
@@ -161,6 +165,15 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return -EFAULT;
return ocfs2_group_add(inode, &input);
+ case OCFS2_IOC_REFLINK:
+ if (copy_from_user(&args, (struct reflink_arguments *)arg,
+ sizeof(args)))
+ return -EFAULT;
+ old_path = (const char *)(unsigned long)args.old_path;
+ new_path = (const char *)(unsigned long)args.new_path;
+ preserve = (args.preserve != 0);
+
+ return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
default:
return -ENOTTY;
}
@@ -183,6 +196,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd, unsigned long arg)
case OCFS2_IOC_GROUP_EXTEND:
case OCFS2_IOC_GROUP_ADD:
case OCFS2_IOC_GROUP_ADD64:
+ case OCFS2_IOC_REFLINK:
break;
default:
return -ENOIOCTLCMD;
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index 4a4565b..e9431e4 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -301,6 +301,15 @@ struct ocfs2_new_group_input {
#define OCFS2_IOC_GROUP_ADD _IOW('o', 2,struct ocfs2_new_group_input)
#define OCFS2_IOC_GROUP_ADD64 _IOW('o', 3,struct ocfs2_new_group_input)
+/* Used to pass 2 file names to reflink. */
+struct reflink_arguments {
+ __u64 old_path;
+ __u64 new_path;
+ __u64 preserve;
+};
+#define OCFS2_IOC_REFLINK _IOW('o', 4, struct reflink_arguments)
+
+
/*
* Journal Flags (ocfs2_dinode.id1.journal1.i_flags)
*/
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 7a8a384..60287fc 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -42,6 +42,11 @@
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include <linux/swap.h>
+#include <linux/security.h>
+#include <linux/fsnotify.h>
+#include <linux/quotaops.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
struct ocfs2_cow_context {
struct inode *inode;
@@ -4145,3 +4150,164 @@ out:
return error;
}
+
+/*
+ * Below here are the bits used by OCFS2_IOC_REFLINK() to fake
+ * sys_reflink(). This will go away when vfs_reflink() exists in
+ * fs/namei.c.
+ */
+
+/* copied from may_create in VFS. */
+static inline int ocfs2_may_create(struct inode *dir, struct dentry *child)
+{
+ if (child->d_inode)
+ return -EEXIST;
+ if (IS_DEADDIR(dir))
+ return -ENOENT;
+ return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+}
+
+/* copied from user_path_parent. */
+static int ocfs2_user_path_parent(const char __user *path,
+ struct nameidata *nd, char **name)
+{
+ char *s = getname(path);
+ int error;
+
+ if (IS_ERR(s))
+ return PTR_ERR(s);
+
+ error = path_lookup(s, LOOKUP_PARENT, nd);
+ if (error)
+ putname(s);
+ else
+ *name = s;
+
+ return error;
+}
+
+/**
+ * ocfs2_vfs_reflink - Create a reference-counted link
+ *
+ * @old_dentry: source dentry + inode
+ * @dir: directory to create the target
+ * @new_dentry: target dentry
+ * @preserve: if true, preserve all file attributes
+ */
+int ocfs2_vfs_reflink(struct dentry *old_dentry, struct inode *dir,
+ struct dentry *new_dentry, bool preserve)
+{
+ struct inode *inode = old_dentry->d_inode;
+ int error;
+
+ if (!inode)
+ return -ENOENT;
+
+ error = ocfs2_may_create(dir, new_dentry);
+ if (error)
+ return error;
+
+ if (dir->i_sb != inode->i_sb)
+ return -EXDEV;
+
+ /*
+ * A reflink to an append-only or immutable file cannot be created.
+ */
+ if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+ return -EPERM;
+
+ /* Only regular files can be reflinked. */
+ if (!S_ISREG(inode->i_mode))
+ return -EPERM;
+
+ /*
+ * If the caller wants to preserve ownership, they require the
+ * rights to do so.
+ */
+ if (preserve) {
+ if ((current_fsuid() != inode->i_uid) && !capable(CAP_CHOWN))
+ return -EPERM;
+ if (!in_group_p(inode->i_gid) && !capable(CAP_CHOWN))
+ return -EPERM;
+ }
+
+ /*
+ * If the caller is modifying any aspect of the attributes, they
+ * are not creating a snapshot. They need read permission on the
+ * file.
+ */
+ if (!preserve) {
+ error = inode_permission(inode, MAY_READ);
+ if (error)
+ return error;
+ }
+
+ mutex_lock(&inode->i_mutex);
+ vfs_dq_init(dir);
+ error = ocfs2_reflink(old_dentry, dir, new_dentry, preserve);
+ mutex_unlock(&inode->i_mutex);
+ if (!error)
+ fsnotify_create(dir, new_dentry);
+ return error;
+}
+/*
+ * Most codes are copied from sys_linkat.
+ */
+int ocfs2_reflink_ioctl(struct inode *inode,
+ const char __user *oldname,
+ const char __user *newname,
+ bool preserve)
+{
+ struct dentry *new_dentry;
+ struct nameidata nd;
+ struct path old_path;
+ int error;
+ char *to = NULL;
+
+ if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)))
+ return -EOPNOTSUPP;
+
+ error = user_path_at(AT_FDCWD, oldname, 0, &old_path);
+ if (error) {
+ mlog_errno(error);
+ return error;
+ }
+
+ error = ocfs2_user_path_parent(newname, &nd, &to);
+ if (error) {
+ mlog_errno(error);
+ goto out;
+ }
+
+ error = -EXDEV;
+ if (old_path.mnt != nd.path.mnt)
+ goto out_release;
+ new_dentry = lookup_create(&nd, 0);
+ error = PTR_ERR(new_dentry);
+ if (IS_ERR(new_dentry)) {
+ mlog_errno(error);
+ goto out_unlock;
+ }
+
+ error = mnt_want_write(nd.path.mnt);
+ if (error) {
+ mlog_errno(error);
+ goto out_dput;
+ }
+
+ error = ocfs2_vfs_reflink(old_path.dentry,
+ nd.path.dentry->d_inode,
+ new_dentry, preserve);
+ mnt_drop_write(nd.path.mnt);
+out_dput:
+ dput(new_dentry);
+out_unlock:
+ mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+out_release:
+ path_put(&nd.path);
+ putname(to);
+out:
+ path_put(&old_path);
+
+ return error;
+}
diff --git a/fs/ocfs2/refcounttree.h b/fs/ocfs2/refcounttree.h
index 2c238e6..c1d19b1 100644
--- a/fs/ocfs2/refcounttree.h
+++ b/fs/ocfs2/refcounttree.h
@@ -99,4 +99,8 @@ int ocfs2_increase_refcount(handle_t *handle,
u64 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
+int ocfs2_reflink_ioctl(struct inode *inode,
+ const char __user *oldname,
+ const char __user *newname,
+ bool preserve);
#endif /* OCFS2_REFCOUNTTREE_H */
--
1.6.2.rc2.16.gf474c
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