This implements reflinkat(2) and reflink(2). See
Documentation/reflink.txt for a description of the reflink(2) system
call.
XXX: Currently only adds the x86_32 linkage. The rest of the
architectures belong here too.
Signed-off-by: Joel Becker <joel.becker@xxxxxxxxxx>
---
arch/x86/include/asm/unistd_32.h | 1 +
arch/x86/kernel/syscall_table_32.S | 1 +
fs/namei.c | 56 ++++++++++++++++++++++++++++++++++++
3 files changed, 58 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
index 6e72d74..ea8eb94 100644
--- a/arch/x86/include/asm/unistd_32.h
+++ b/arch/x86/include/asm/unistd_32.h
@@ -340,6 +340,7 @@
#define __NR_inotify_init1 332
#define __NR_preadv 333
#define __NR_pwritev 334
+#define __NR_reflink 335
#ifdef __KERNEL__
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index ff5c873..866705d 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -334,3 +334,4 @@ ENTRY(sys_call_table)
.long sys_inotify_init1
.long sys_preadv
.long sys_pwritev
+ .long sys_reflink /* 335 */
diff --git a/fs/namei.c b/fs/namei.c
index 45cbe7a..cf739a3 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2524,6 +2524,62 @@ int vfs_reflink(struct dentry *old_dentry, struct inode *dir, struct dentry *new
return error;
}
+SYSCALL_DEFINE5(reflinkat, int, olddfd, const char __user *, oldname,
+ int, newdfd, const char __user *, newname, int, flags)
+{
+ struct dentry *new_dentry;
+ struct nameidata nd;
+ struct path old_path;
+ int error;
+ char *to;
+
+ if ((flags & ~AT_SYMLINK_FOLLOW) != 0)
+ return -EINVAL;
+
+ error = user_path_at(olddfd, oldname,
+ flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
+ &old_path);
+ if (error)
+ return error;
+
+ error = user_path_parent(newdfd, newname, &nd, &to);
+ if (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))
+ goto out_unlock;
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ goto out_dput;
+ error = security_path_mknod(&nd.path, new_dentry,
+ old_path.dentry->d_inode->i_mode, 0);
+ if (error)
+ goto out_drop_write;
+ error = vfs_reflink(old_path.dentry, nd.path.dentry->d_inode, new_dentry);
+out_drop_write:
+ 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;
+}
+
+SYSCALL_DEFINE2(reflink, const char __user *, oldname, const char __user *, newname)
+{
+ return sys_reflinkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+}
+
/*
* The worst of all namespace operations - renaming directory. "Perverted"
--
1.6.1.3
--
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