[PATCH -V21 00/12] Generic name to handle and open by handle syscalls

[PATCH -V21 00/12] Generic name to handle and open by handle syscalls

[Aneesh Kumar K.V]

Hi,

The below set of patches implement open by handle support using exportfs
operations. This allows user space application to map a file name to file
handle and later open the file using handle. This should be usable
for userspace NFS [1] and 9P server [2]. XFS already support this with the ioctls
XFS_IOC_PATH_TO_HANDLE and XFS_IOC_OPEN_BY_HANDLE.

[1] http://nfs-ganesha.sourceforge.net/
[2] http://thread.gmane.org/gmane.comp.emulators.qemu/68992

git repo for the patchset at:
git://git.kernel.org/pub/scm/linux/kernel/git/kvaneesh/linux-open-handle.git open-by-handle

Test case can be found at
http://git.kernel.org/?p=fs/ext2/kvaneesh/handle-test.git
git://git.kernel.org/pub/scm/fs/ext2/kvaneesh/handle-test.git

Changes from V20:
a) Use better variable names
b) change handle_size type to __u32
c) max handle size is now nfsv4 handle size. Considering file system would
   want to support a handle that can fit into nfsv4 handle size limiting
   max handle size to 128 rather than 4096 is the right thing.
d) I didn't add Ceph changes in the series. I am expecting the changes
   will go via Ceph tree.

-aneesh

[PATCH -V21 01/12] exportfs: Return the minimum required handle size

[Aneesh Kumar K.V]

The exportfs encode handle function should return the minimum required
handle size. This helps user to find out the handle size by passing 0
handle size in the first step and then redoing to the call again with
the returned handle size value.

Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/btrfs/export.c             |    8 ++++++--
 fs/exportfs/expfs.c           |    9 +++++++--
 fs/fat/inode.c                |    4 +++-
 fs/fuse/inode.c               |    4 +++-
 fs/gfs2/export.c              |    8 ++++++--
 fs/isofs/export.c             |    8 ++++++--
 fs/ocfs2/export.c             |    8 ++++++--
 fs/reiserfs/inode.c           |    7 ++++++-
 fs/udf/namei.c                |    7 ++++++-
 fs/xfs/linux-2.6/xfs_export.c |    4 +++-
 include/linux/exportfs.h      |    6 ++++--
 mm/shmem.c                    |    4 +++-
 12 files changed, 59 insertions(+), 18 deletions(-)

diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 951ef09..5f8ee5a 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -21,9 +21,13 @@ static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
 	int len = *max_len;
 	int type;
 
-	if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) ||
-	    (connectable && len < BTRFS_FID_SIZE_CONNECTABLE))
+	if (connectable && (len < BTRFS_FID_SIZE_CONNECTABLE)) {
+		*max_len = BTRFS_FID_SIZE_CONNECTABLE;
 		return 255;
+	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {
+		*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;
+		return 255;
+	}
 
 	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;
 	type = FILEID_BTRFS_WITHOUT_PARENT;
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index e9e1759..cfee0f0 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -319,9 +319,14 @@ static int export_encode_fh(struct dentry *dentry, struct fid *fid,
 	struct inode * inode = dentry->d_inode;
 	int len = *max_len;
 	int type = FILEID_INO32_GEN;
-	
-	if (len < 2 || (connectable && len < 4))
+
+	if (connectable && (len < 4)) {
+		*max_len = 4;
+		return 255;
+	} else if (len < 2) {
+		*max_len = 2;
 		return 255;
+	}
 
 	len = 2;
 	fid->i32.ino = inode->i_ino;
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 8300580..0812d29 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -759,8 +759,10 @@ fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
 	struct inode *inode =  de->d_inode;
 	u32 ipos_h, ipos_m, ipos_l;
 
-	if (len < 5)
+	if (len < 5) {
+		*lenp = 5;
 		return 255; /* no room */
+	}
 
 	ipos_h = MSDOS_I(inode)->i_pos >> 8;
 	ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index da9e6e1..52adfcd 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -640,8 +640,10 @@ static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
 	u64 nodeid;
 	u32 generation;
 
-	if (*max_len < len)
+	if (*max_len < len) {
+		*max_len = len;
 		return  255;
+	}
 
 	nodeid = get_fuse_inode(inode)->nodeid;
 	generation = inode->i_generation;
diff --git a/fs/gfs2/export.c b/fs/gfs2/export.c
index dfe237a..bd0fd68 100644
--- a/fs/gfs2/export.c
+++ b/fs/gfs2/export.c
@@ -36,9 +36,13 @@ static int gfs2_encode_fh(struct dentry *dentry, __u32 *p, int *len,
 	struct super_block *sb = inode->i_sb;
 	struct gfs2_inode *ip = GFS2_I(inode);
 
-	if (*len < GFS2_SMALL_FH_SIZE ||
-	    (connectable && *len < GFS2_LARGE_FH_SIZE))
+	if (connectable && (*len < GFS2_LARGE_FH_SIZE)) {
+		*len = GFS2_LARGE_FH_SIZE;
 		return 255;
+	} else if (*len < GFS2_SMALL_FH_SIZE) {
+		*len = GFS2_SMALL_FH_SIZE;
+		return 255;
+	}
 
 	fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
 	fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
diff --git a/fs/isofs/export.c b/fs/isofs/export.c
index ed752cb..dd4687f 100644
--- a/fs/isofs/export.c
+++ b/fs/isofs/export.c
@@ -124,9 +124,13 @@ isofs_export_encode_fh(struct dentry *dentry,
 	 * offset of the inode and the upper 16 bits of fh32[1] to
 	 * hold the offset of the parent.
 	 */
-
-	if (len < 3 || (connectable && len < 5))
+	if (connectable && (len < 5)) {
+		*max_len = 5;
+		return 255;
+	} else if (len < 3) {
+		*max_len = 3;
 		return 255;
+	}
 
 	len = 3;
 	fh32[0] = ei->i_iget5_block;
diff --git a/fs/ocfs2/export.c b/fs/ocfs2/export.c
index 19ad145..84559d0 100644
--- a/fs/ocfs2/export.c
+++ b/fs/ocfs2/export.c
@@ -201,8 +201,12 @@ static int ocfs2_encode_fh(struct dentry *dentry, u32 *fh_in, int *max_len,
 		   dentry->d_name.len, dentry->d_name.name,
 		   fh, len, connectable);
 
-	if (len < 3 || (connectable && len < 6)) {
-		mlog(ML_ERROR, "fh buffer is too small for encoding\n");
+	if (connectable && (len < 6)) {
+		*max_len = 6;
+		type = 255;
+		goto bail;
+	} else if (len < 3) {
+		*max_len = 3;
 		type = 255;
 		goto bail;
 	}
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index caa7583..44eebc7 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -1595,8 +1595,13 @@ int reiserfs_encode_fh(struct dentry *dentry, __u32 * data, int *lenp,
 	struct inode *inode = dentry->d_inode;
 	int maxlen = *lenp;
 
-	if (maxlen < 3)
+	if (need_parent && (maxlen < 5)) {
+		*lenp = 5;
 		return 255;
+	} else if (maxlen < 3) {
+		*lenp = 3;
+		return 255;
+	}
 
 	data[0] = inode->i_ino;
 	data[1] = le32_to_cpu(INODE_PKEY(inode)->k_dir_id);
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index bf5fc67..20db42f 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -1336,8 +1336,13 @@ static int udf_encode_fh(struct dentry *de, __u32 *fh, int *lenp,
 	struct fid *fid = (struct fid *)fh;
 	int type = FILEID_UDF_WITHOUT_PARENT;
 
-	if (len < 3 || (connectable && len < 5))
+	if (connectable && (len < 5)) {
+		*lenp = 5;
+		return 255;
+	} else if (len < 3) {
+		*lenp = 3;
 		return 255;
+	}
 
 	*lenp = 3;
 	fid->udf.block = location.logicalBlockNum;
diff --git a/fs/xfs/linux-2.6/xfs_export.c b/fs/xfs/linux-2.6/xfs_export.c
index 3764d74..7132d7c 100644
--- a/fs/xfs/linux-2.6/xfs_export.c
+++ b/fs/xfs/linux-2.6/xfs_export.c
@@ -81,8 +81,10 @@ xfs_fs_encode_fh(
 	 * seven combinations work.  The real answer is "don't use v2".
 	 */
 	len = xfs_fileid_length(fileid_type);
-	if (*max_len < len)
+	if (*max_len < len) {
+		*max_len = len;
 		return 255;
+	}
 	*max_len = len;
 
 	switch (fileid_type) {
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index a9cd507..df05257 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -108,8 +108,10 @@ struct fid {
  *    set, the encode_fh() should store sufficient information so that a good
  *    attempt can be made to find not only the file but also it's place in the
  *    filesystem.   This typically means storing a reference to de->d_parent in
- *    the filehandle fragment.  encode_fh() should return the number of bytes
- *    stored or a negative error code such as %-ENOSPC
+ *    the filehandle fragment.  encode_fh() should return the fileid_type on
+ *    success and on error returns 255 (if the space needed to encode fh is
+ *    greater than @max_len*4 bytes). On error @max_len contains the minimum
+ *    size(in 4 byte unit) needed to encode the file handle.
  *
  * fh_to_dentry:
  *    @fh_to_dentry is given a &struct super_block (@sb) and a file handle
diff --git a/mm/shmem.c b/mm/shmem.c
index 080b09a..9e6d86f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2143,8 +2143,10 @@ static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
 {
 	struct inode *inode = dentry->d_inode;
 
-	if (*len < 3)
+	if (*len < 3) {
+		*len = 3;
 		return 255;
+	}
 
 	if (hlist_unhashed(&inode->i_hash)) {
 		/* Unfortunately insert_inode_hash is not idempotent,
-- 
1.7.0.4

[PATCH -V21 02/12] vfs: Add name to file handle conversion support

[Aneesh Kumar K.V]

The syscall also return mount id which can be used
to lookup file system specific information such as uuid
in /proc/<pid>/mountinfo

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/open.c                |  135 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/exportfs.h |    3 +
 include/linux/fs.h       |    7 +++
 include/linux/syscalls.h |    5 ++-
 4 files changed, 149 insertions(+), 1 deletions(-)

diff --git a/fs/open.c b/fs/open.c
index d74e198..0475a35 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -30,6 +30,7 @@
 #include <linux/fs_struct.h>
 #include <linux/ima.h>
 #include <linux/dnotify.h>
+#include <linux/exportfs.h>
 
 #include "internal.h"
 
@@ -1042,3 +1043,137 @@ int nonseekable_open(struct inode *inode, struct file *filp)
 }
 
 EXPORT_SYMBOL(nonseekable_open);
+
+#ifdef CONFIG_EXPORTFS
+static long do_sys_name_to_handle(struct path *path,
+				  struct file_handle __user *ufh,
+				  int __user *mnt_id)
+{
+	long retval;
+	struct file_handle f_handle;
+	int handle_dwords, handle_bytes;
+	struct file_handle *handle = NULL;
+
+	if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle))) {
+		retval = -EFAULT;
+		goto err_out;
+	}
+	if (f_handle.handle_bytes > MAX_HANDLE_SZ) {
+		retval = -EINVAL;
+		goto err_out;
+	}
+	handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
+			 GFP_KERNEL);
+	if (!handle) {
+		retval = -ENOMEM;
+		goto err_out;
+	}
+
+	/* convert handle size to  multiple of sizeof(u32) */
+	handle_dwords = f_handle.handle_bytes >> 2;
+
+	/* we ask for a non connected handle */
+	retval = exportfs_encode_fh(path->dentry,
+				    (struct fid *)handle->f_handle,
+				    &handle_dwords,  0);
+	handle->handle_type = retval;
+	/* convert handle size to bytes */
+	handle_bytes = handle_dwords * sizeof(u32);
+	handle->handle_bytes = handle_bytes;
+	if ((handle->handle_bytes > f_handle.handle_bytes) ||
+	    (retval == 255) || (retval == -ENOSPC)) {
+		/* As per old exportfs_encode_fh documentation
+		 * we could return ENOSPC to indicate overflow
+		 * But file system returned 255 always. So handle
+		 * both the values
+		 */
+		/*
+		 * set the handle size to zero so we copy only
+		 * non variable part of the file_handle
+		 */
+		handle_bytes = 0;
+		retval = -EOVERFLOW;
+	} else
+		retval = 0;
+	/* copy the mount id */
+	if (copy_to_user(mnt_id, &path->mnt->mnt_id, sizeof(*mnt_id))) {
+		retval = -EFAULT;
+		goto err_free_out;
+	}
+	if (copy_to_user(ufh, handle,
+			 sizeof(struct file_handle) + handle_bytes))
+		retval = -EFAULT;
+err_free_out:
+	kfree(handle);
+err_out:
+	return retval;
+}
+
+/**
+ * sys_name_to_handle_at: convert name to handle
+ * @dfd: directory relative to which name is interpreted if not absolute
+ * @name: name that should be converted to handle.
+ * @handle: resulting file handle
+ * @mnt_id: mount id of the file system containing the file
+ * @flag: flag value to indicate whether to follow symlink or not
+ *
+ * @handle->handle_size indicate the space available to store the
+ * variable part of the file handle in bytes. If there is not
+ * enough space, the field is updated to return the minimum
+ * value required.
+ */
+SYSCALL_DEFINE5(name_to_handle_at, int, dfd, const char __user *, name,
+		struct file_handle __user *, handle, int __user*, mnt_id,
+		int, flag)
+{
+
+	int follow;
+	int fput_needed;
+	long ret = -EINVAL;
+	struct path path, *pp;
+	struct file *file = NULL;
+
+	if ((flag & ~AT_SYMLINK_FOLLOW) != 0)
+		goto err_out;
+
+	if (name == NULL && dfd != AT_FDCWD) {
+		file = fget_light(dfd, &fput_needed);
+		if (file) {
+			pp = &file->f_path;
+			ret = 0;
+		} else
+			ret = -EBADF;
+	} else {
+		follow = (flag & AT_SYMLINK_FOLLOW) ? LOOKUP_FOLLOW : 0;
+		ret = user_path_at(dfd, name, follow, &path);
+		pp = &path;
+	}
+	if (ret)
+		goto err_out;
+	/*
+	 * We need t make sure wether the file system
+	 * support decoding of the file handle
+	 */
+	if (!pp->mnt->mnt_sb->s_export_op ||
+	    !pp->mnt->mnt_sb->s_export_op->fh_to_dentry) {
+		ret = -EOPNOTSUPP;
+		goto out_path;
+	}
+	ret = do_sys_name_to_handle(pp, handle, mnt_id);
+
+out_path:
+	if (file)
+		fput_light(file, fput_needed);
+	else
+		path_put(&path);
+err_out:
+	return ret;
+}
+#else
+SYSCALL_DEFINE5(name_to_handle_at, int, dfd, const char __user *, name,
+		struct file_handle __user *, handle, int __user *, mnt_id,
+		int, flag)
+{
+	return -ENOSYS;
+}
+#endif
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index df05257..561837d 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -8,6 +8,9 @@ struct inode;
 struct super_block;
 struct vfsmount;
 
+/* limit the handle size to NFSv4 handle size now */
+#define MAX_HANDLE_SZ 128
+
 /*
  * The fileid_type identifies how the file within the filesystem is encoded.
  * In theory this is freely set and parsed by the filesystem, but we try to
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 63d069b..1c7c6ca 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -948,6 +948,13 @@ struct file {
 #endif
 };
 
+struct file_handle {
+	__u32 handle_bytes;
+	int handle_type;
+	/* file identifier */
+	unsigned char f_handle[0];
+};
+
 #define get_file(x)	atomic_long_inc(&(x)->f_count)
 #define fput_atomic(x)	atomic_long_add_unless(&(x)->f_count, -1, 1)
 #define file_count(x)	atomic_long_read(&(x)->f_count)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e6319d1..6ab4d07 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -62,6 +62,7 @@ struct robust_list_head;
 struct getcpu_cache;
 struct old_linux_dirent;
 struct perf_event_attr;
+struct file_handle;
 
 #include <linux/types.h>
 #include <linux/aio_abi.h>
@@ -831,5 +832,7 @@ asmlinkage long sys_mmap_pgoff(unsigned long addr, unsigned long len,
 			unsigned long prot, unsigned long flags,
 			unsigned long fd, unsigned long pgoff);
 asmlinkage long sys_old_mmap(struct mmap_arg_struct __user *arg);
-
+asmlinkage long sys_name_to_handle_at(int dfd, const char __user *name,
+				      struct file_handle __user *handle,
+				      int __user *mnt_id, int flag);
 #endif
-- 
1.7.0.4

[PATCH -V21 03/12] vfs: Add open by file handle support

[Aneesh Kumar K.V]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/compat.c              |   11 +++
 fs/exportfs/expfs.c      |    2 +
 fs/namei.c               |  223 +++++++++++++++++++++++++++++++++++++++++++---
 fs/open.c                |   32 ++++++-
 include/linux/fs.h       |   10 ++-
 include/linux/namei.h    |    1 +
 include/linux/syscalls.h |    3 +
 7 files changed, 263 insertions(+), 19 deletions(-)

diff --git a/fs/compat.c b/fs/compat.c
index 0644a15..4a423fa 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -2334,3 +2334,14 @@ asmlinkage long compat_sys_timerfd_gettime(int ufd,
 }
 
 #endif /* CONFIG_TIMERFD */
+
+/*
+ * Exactly like fs/open.c:sys_open_by_handle_at(), except that it
+ * doesn't set the O_LARGEFILE flag.
+ */
+asmlinkage long
+compat_sys_open_by_handle_at(int mountdirfd,
+			     struct file_handle __user *handle, int flags)
+{
+	return do_handle_open(mountdirfd, handle, flags);
+}
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index cfee0f0..05a1179 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -373,6 +373,8 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
 	/*
 	 * Try to get any dentry for the given file handle from the filesystem.
 	 */
+	if (!nop || !nop->fh_to_dentry)
+		return ERR_PTR(-ESTALE);
 	result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
 	if (!result)
 		result = ERR_PTR(-ESTALE);
diff --git a/fs/namei.c b/fs/namei.c
index 24896e8..c52a9d5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -32,6 +32,7 @@
 #include <linux/fcntl.h>
 #include <linux/device_cgroup.h>
 #include <linux/fs_struct.h>
+#include <linux/exportfs.h>
 #include <asm/uaccess.h>
 
 #include "internal.h"
@@ -1050,6 +1051,29 @@ out_fail:
 	return retval;
 }
 
+struct vfsmount *get_vfsmount_from_fd(int fd)
+{
+	int fput_needed;
+	struct path path;
+	struct file *filep;
+
+	if (fd == AT_FDCWD) {
+		struct fs_struct *fs = current->fs;
+		spin_lock(&fs->lock);
+		path = fs->pwd;
+		mntget(path.mnt);
+		spin_unlock(&fs->lock);
+	} else {
+		filep = fget_light(fd, &fput_needed);
+		if (!filep)
+			return ERR_PTR(-EBADF);
+		path = filep->f_path;
+		mntget(path.mnt);
+		fput_light(filep, fput_needed);
+	}
+	return path.mnt;
+}
+
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
 static int do_path_lookup(int dfd, const char *name,
 				unsigned int flags, struct nameidata *nd)
@@ -1537,26 +1561,30 @@ static int open_will_truncate(int flag, struct inode *inode)
 	return (flag & O_TRUNC);
 }
 
-static struct file *finish_open(struct nameidata *nd,
+static struct file *finish_open(struct file *filp, struct path *path,
 				int open_flag, int acc_mode)
 {
-	struct file *filp;
-	int will_truncate;
 	int error;
+	int will_truncate;
 
-	will_truncate = open_will_truncate(open_flag, nd->path.dentry->d_inode);
+	will_truncate = open_will_truncate(open_flag, path->dentry->d_inode);
 	if (will_truncate) {
-		error = mnt_want_write(nd->path.mnt);
+		error = mnt_want_write(path->mnt);
 		if (error)
 			goto exit;
 	}
-	error = may_open(&nd->path, acc_mode, open_flag);
+	error = may_open(path, acc_mode, open_flag);
 	if (error) {
 		if (will_truncate)
-			mnt_drop_write(nd->path.mnt);
+			mnt_drop_write(path->mnt);
 		goto exit;
 	}
-	filp = nameidata_to_filp(nd);
+	/* Has the filesystem initialised the file for us? */
+	if (filp->f_path.dentry == NULL)
+		filp = __dentry_open(path->dentry, path->mnt, filp,
+				     NULL, current_cred());
+	else
+		path_put(path);
 	if (!IS_ERR(filp)) {
 		error = ima_file_check(filp, acc_mode);
 		if (error) {
@@ -1566,7 +1594,7 @@ static struct file *finish_open(struct nameidata *nd,
 	}
 	if (!IS_ERR(filp)) {
 		if (will_truncate) {
-			error = handle_truncate(&nd->path);
+			error = handle_truncate(path);
 			if (error) {
 				fput(filp);
 				filp = ERR_PTR(error);
@@ -1579,13 +1607,17 @@ static struct file *finish_open(struct nameidata *nd,
 	 * on its behalf.
 	 */
 	if (will_truncate)
-		mnt_drop_write(nd->path.mnt);
+		mnt_drop_write(path->mnt);
 	return filp;
 
 exit:
-	if (!IS_ERR(nd->intent.open.file))
-		release_open_intent(nd);
-	path_put(&nd->path);
+	if (!IS_ERR(filp)) {
+		if (filp->f_path.dentry == NULL)
+			put_filp(filp);
+		else
+			fput(filp);
+	}
+	path_put(path);
 	return ERR_PTR(error);
 }
 
@@ -1719,7 +1751,9 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	if (S_ISDIR(path->dentry->d_inode->i_mode))
 		goto exit;
 ok:
-	filp = finish_open(nd, open_flag, acc_mode);
+	filp = finish_open(nd->intent.open.file, &nd->path,
+			   open_flag, acc_mode);
+
 	return filp;
 
 exit_mutex_unlock:
@@ -1892,6 +1926,167 @@ struct file *filp_open(const char *filename, int flags, int mode)
 }
 EXPORT_SYMBOL(filp_open);
 
+#ifdef CONFIG_EXPORTFS
+static int vfs_dentry_acceptable(void *context, struct dentry *dentry)
+{
+	return 1;
+}
+
+static int do_handle_to_path(int mountdirfd, struct file_handle *handle,
+			     struct path *path)
+{
+	int retval = 0;
+	int handle_dwords;
+
+	path->mnt = get_vfsmount_from_fd(mountdirfd);
+	if (IS_ERR(path->mnt)) {
+		retval = PTR_ERR(path->mnt);
+		goto out_err;
+	}
+	/* change the handle size to multiple of sizeof(u32) */
+	handle_dwords = handle->handle_bytes >> 2;
+	path->dentry = exportfs_decode_fh(path->mnt,
+					  (struct fid *)handle->f_handle,
+					  handle_dwords, handle->handle_type,
+					  vfs_dentry_acceptable, NULL);
+	if (IS_ERR(path->dentry)) {
+		retval = PTR_ERR(path->dentry);
+		goto out_mnt;
+	}
+	return 0;
+out_mnt:
+	mntput(path->mnt);
+out_err:
+	return retval;
+}
+
+int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
+		   struct path *path)
+{
+	int retval = 0;
+	struct file_handle f_handle;
+	struct file_handle *handle = NULL;
+
+	/*
+	 * With handle we don't look at the execute bit on the
+	 * the directory. Ideally we would like CAP_DAC_SEARCH.
+	 * But we don't have that
+	 */
+	if (!capable(CAP_DAC_READ_SEARCH)) {
+		retval = -EPERM;
+		goto out_err;
+	}
+	if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle))) {
+		retval = -EFAULT;
+		goto out_err;
+	}
+	if ((f_handle.handle_bytes > MAX_HANDLE_SZ) ||
+	    (f_handle.handle_bytes == 0)) {
+		retval = -EINVAL;
+		goto out_err;
+	}
+	handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_bytes,
+			 GFP_KERNEL);
+	if (!handle) {
+		retval = -ENOMEM;
+		goto out_err;
+	}
+	/* copy the full handle */
+	if (copy_from_user(handle, ufh,
+			   sizeof(struct file_handle) +
+			   f_handle.handle_bytes)) {
+		retval = -EFAULT;
+		goto out_handle;
+	}
+
+	retval = do_handle_to_path(mountdirfd, handle, path);
+
+out_handle:
+	kfree(handle);
+out_err:
+	return retval;
+}
+#else
+int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
+		   struct path *path)
+{
+	return -ENOSYS;
+}
+#endif
+
+long do_handle_open(int mountdirfd,
+		    struct file_handle __user *ufh, int open_flag)
+{
+	long retval = 0;
+	int fd, acc_mode;
+	struct path path;
+	struct file *filp;
+
+	/* can't use O_CREATE with open_by_handle */
+	if (open_flag & O_CREAT) {
+		retval = -EINVAL;
+		goto out_err;
+	}
+	retval = handle_to_path(mountdirfd, ufh, &path);
+	if (retval)
+		goto out_err;
+
+	if ((open_flag & O_DIRECTORY) &&
+	    !S_ISDIR(path.dentry->d_inode->i_mode)) {
+		retval = -ENOTDIR;
+		goto out_path;
+	}
+	/*
+	 * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
+	 * check for O_DSYNC if the need any syncing at all we enforce it's
+	 * always set instead of having to deal with possibly weird behaviour
+	 * for malicious applications setting only __O_SYNC.
+	 */
+	if (open_flag & __O_SYNC)
+		open_flag |= O_DSYNC;
+
+	acc_mode = MAY_OPEN | ACC_MODE(open_flag);
+
+	/* O_TRUNC implies we need access checks for write permissions */
+	if (open_flag & O_TRUNC)
+		acc_mode |= MAY_WRITE;
+	/*
+	 * Allow the LSM permission hook to distinguish append
+	 * access from general write access.
+	 */
+	if (open_flag & O_APPEND)
+		acc_mode |= MAY_APPEND;
+
+	fd = get_unused_fd_flags(open_flag);
+	if (fd < 0) {
+		retval = fd;
+		goto out_path;
+	}
+	filp = get_empty_filp();
+	if (!filp) {
+		retval = -ENFILE;
+		goto out_free_fd;
+	}
+	filp->f_flags = open_flag;
+	filp = finish_open(filp, &path, open_flag, acc_mode);
+	if (IS_ERR(filp)) {
+		put_unused_fd(fd);
+		retval =  PTR_ERR(filp);
+	} else {
+		retval = fd;
+		fsnotify_open(filp);
+		fd_install(fd, filp);
+	}
+	return retval;
+
+out_free_fd:
+	put_unused_fd(fd);
+out_path:
+	path_put(&path);
+out_err:
+	return retval;
+}
+
 /**
  * lookup_create - lookup a dentry, creating it if it doesn't exist
  * @nd: nameidata info
diff --git a/fs/open.c b/fs/open.c
index 0475a35..5447d4d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -652,10 +652,10 @@ static inline int __get_file_write_access(struct inode *inode,
 	return error;
 }
 
-static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
-					struct file *f,
-					int (*open)(struct inode *, struct file *),
-					const struct cred *cred)
+struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
+			   struct file *f,
+			   int (*open)(struct inode *, struct file *),
+			   const struct cred *cred)
 {
 	struct inode *inode;
 	int error;
@@ -1177,3 +1177,27 @@ SYSCALL_DEFINE5(name_to_handle_at, int, dfd, const char __user *, name,
 	return -ENOSYS;
 }
 #endif
+
+/**
+ * sys_open_by_handle_at: Open the file handle
+ * @mountdirfd: directory file descriptor
+ * @handle: file handle to be opened
+ * @flag: open flags.
+ *
+ * @mountdirfd indicate the directory file descriptor
+ * of the mount point. file handle is decoded relative
+ * to the vfsmount pointed by the @mountdirfd. @flags
+ * value is same as the open(2) flags.
+ */
+SYSCALL_DEFINE3(open_by_handle_at, int, mountdirfd,
+		struct file_handle __user *, handle,
+		int, flags)
+{
+	long ret;
+
+	if (force_o_largefile())
+		flags |= O_LARGEFILE;
+
+	ret = do_handle_open(mountdirfd, handle, flags);
+	return ret;
+}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1c7c6ca..4421f15 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1937,6 +1937,10 @@ extern int do_fallocate(struct file *file, int mode, loff_t offset,
 extern long do_sys_open(int dfd, const char __user *filename, int flags,
 			int mode);
 extern struct file *filp_open(const char *, int, int);
+struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
+			   struct file *f,
+			   int (*open)(struct inode *, struct file *),
+			   const struct cred *cred);
 extern struct file * dentry_open(struct dentry *, struct vfsmount *, int,
 				 const struct cred *);
 extern int filp_close(struct file *, fl_owner_t id);
@@ -2148,11 +2152,15 @@ extern void free_write_pipe(struct file *);
 
 extern struct file *do_filp_open(int dfd, const char *pathname,
 		int open_flag, int mode, int acc_mode);
+extern int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
+			  struct path *path);
+extern long do_handle_open(int mountdirfd,
+			   struct file_handle __user *ufh, int open_flag);
 extern int may_open(struct path *, int, int);
 
 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
 extern struct file * open_exec(const char *);
- 
+
 /* fs/dcache.c -- generic fs support functions */
 extern int is_subdir(struct dentry *, struct dentry *);
 extern int path_is_under(struct path *, struct path *);
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 05b441d..827aef0 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -64,6 +64,7 @@ extern int user_path_at(int, const char __user *, unsigned, struct path *);
 #define user_path_dir(name, path) \
 	user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, path)
 
+extern struct vfsmount *get_vfsmount_from_fd(int);
 extern int kern_path(const char *, unsigned, struct path *);
 
 extern int path_lookup(const char *, unsigned, struct nameidata *);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 6ab4d07..89a0ade 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -835,4 +835,7 @@ asmlinkage long sys_old_mmap(struct mmap_arg_struct __user *arg);
 asmlinkage long sys_name_to_handle_at(int dfd, const char __user *name,
 				      struct file_handle __user *handle,
 				      int __user *mnt_id, int flag);
+asmlinkage long sys_open_by_handle_at(int mountdirfd,
+				      struct file_handle __user *handle,
+				      int flags);
 #endif
-- 
1.7.0.4

[PATCH -V21 04/12] vfs: Add handle based readlink syscall

[Aneesh Kumar K.V]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/stat.c                |   28 ++++++++++++++++++++++++++++
 include/linux/syscalls.h |    3 +++
 2 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/fs/stat.c b/fs/stat.c
index 12e90e2..29052eb 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -319,6 +319,34 @@ SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
 	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
 }
 
+SYSCALL_DEFINE4(handle_readlink, int, mountdirfd,
+		struct file_handle __user *, ufh,
+		char __user *, buf, int, bufsiz)
+{
+	long retval = 0;
+	struct path path;
+	struct inode *inode;
+
+	if (bufsiz <= 0)
+		return -EINVAL;
+	retval = handle_to_path(mountdirfd, ufh, &path);
+	if (retval)
+		goto out_err;
+
+	inode = path.dentry->d_inode;
+	retval = -EINVAL;
+	if (inode->i_op->readlink) {
+		retval = security_inode_readlink(path.dentry);
+		if (!retval) {
+			touch_atime(path.mnt, path.dentry);
+			retval = inode->i_op->readlink(path.dentry,
+						       buf, bufsiz);
+		}
+	}
+	path_put(&path);
+out_err:
+	return retval;
+}
 
 /* ---------- LFS-64 ----------- */
 #ifdef __ARCH_WANT_STAT64
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 89a0ade..bf03e4a 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -838,4 +838,7 @@ asmlinkage long sys_name_to_handle_at(int dfd, const char __user *name,
 asmlinkage long sys_open_by_handle_at(int mountdirfd,
 				      struct file_handle __user *handle,
 				      int flags);
+asmlinkage long sys_handle_readlink(int mountdirfd,
+				    struct file_handle __user *ufh,
+				    char __user *buf, int bufsiz);
 #endif
-- 
1.7.0.4

[PATCH -V21 05/12] vfs: Add handle based stat syscall

[Aneesh Kumar K.V]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/x86/ia32/sys_ia32.c |   13 +++++++++++++
 fs/stat.c                |   42 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h       |    3 +++
 include/linux/syscalls.h |    9 +++++++++
 4 files changed, 67 insertions(+), 0 deletions(-)

diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index 849813f..7f679e4 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -138,6 +138,19 @@ asmlinkage long sys32_fstatat(unsigned int dfd, const char __user *filename,
 	return cp_stat64(statbuf, &stat);
 }
 
+asmlinkage long sys32_handle_stat64(int mountdirfd,
+				    struct file_handle __user *ufh,
+				    struct stat64 __user *statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = do_handle_stat(mountdirfd, ufh, &stat);
+	if (error)
+		return error;
+	return cp_stat64(statbuf, &stat);
+}
+
 /*
  * Linux/i386 didn't use to be able to handle more than
  * 4 system call parameters, so these system calls used a memory
diff --git a/fs/stat.c b/fs/stat.c
index 29052eb..d448876 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -286,6 +286,35 @@ SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
 	return error;
 }
 
+int do_handle_stat(int mountdirfd, struct file_handle __user *ufh,
+		   struct kstat *stat)
+{
+	struct path path;
+	int error = -EINVAL;
+
+	error = handle_to_path(mountdirfd, ufh, &path);
+	if (error)
+		goto out;
+
+	error = vfs_getattr(path.mnt, path.dentry, stat);
+	path_put(&path);
+out:
+	return error;
+}
+
+SYSCALL_DEFINE3(handle_stat, int, mountdirfd,
+		struct file_handle __user *, ufh,
+		struct stat __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = do_handle_stat(mountdirfd, ufh, &stat);
+	if (error)
+		return error;
+	return cp_new_stat(&stat, statbuf);
+}
+
 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 		char __user *, buf, int, bufsiz)
 {
@@ -434,6 +463,19 @@ SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
 		return error;
 	return cp_new_stat64(&stat, statbuf);
 }
+
+SYSCALL_DEFINE3(handle_stat64, int, mountdirfd,
+		struct file_handle __user *, ufh,
+		struct stat64 __user *, statbuf)
+{
+	struct kstat stat;
+	int error;
+
+	error = do_handle_stat(mountdirfd, ufh, &stat);
+	if (error)
+		return error;
+	return cp_new_stat64(&stat, statbuf);
+}
 #endif /* __ARCH_WANT_STAT64 */
 
 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4421f15..cffe154 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2335,6 +2335,9 @@ extern int vfs_stat(const char __user *, struct kstat *);
 extern int vfs_lstat(const char __user *, struct kstat *);
 extern int vfs_fstat(unsigned int, struct kstat *);
 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
+extern int do_handle_stat(int mountdirfd,
+			  struct file_handle __user *ufh,
+			  struct kstat *stat);
 
 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 		    unsigned long arg);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index bf03e4a..de4f242 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -841,4 +841,13 @@ asmlinkage long sys_open_by_handle_at(int mountdirfd,
 asmlinkage long sys_handle_readlink(int mountdirfd,
 				    struct file_handle __user *ufh,
 				    char __user *buf, int bufsiz);
+#if BITS_PER_LONG == 32
+asmlinkage long sys_handle_stat64(int mountdirfd,
+				  struct file_handle __user *ufh,
+				  struct stat64 __user *statbuf);
+#else
+asmlinkage long sys_handle_stat(int mountdirfd,
+				struct file_handle __user *ufh,
+				struct stat __user *statbuf);
+#endif
 #endif
-- 
1.7.0.4

[PATCH -V21 06/12] vfs: Add handle based link syscall

[Aneesh Kumar K.V]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/namei.c               |   45 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/syscalls.h |    2 ++
 2 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c52a9d5..6bbaff1 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2697,6 +2697,51 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
 	return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
+SYSCALL_DEFINE4(handle_link, int, mountdirfd, struct file_handle __user *, uofh,
+		int, newdfd, const char __user *, newname)
+{
+	char *to;
+	int error;
+	struct dentry *new_dentry;
+	struct nameidata nd;
+	struct path old_path;
+
+	error = handle_to_path(mountdirfd, uofh, &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_link(old_path.dentry, &nd.path, new_dentry);
+	if (error)
+		goto out_drop_write;
+	error = vfs_link(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;
+}
+
 /*
  * The worst of all namespace operations - renaming directory. "Perverted"
  * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index de4f242..278d2ae 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -850,4 +850,6 @@ asmlinkage long sys_handle_stat(int mountdirfd,
 				struct file_handle __user *ufh,
 				struct stat __user *statbuf);
 #endif
+asmlinkage long sys_handle_link(int mountdirfd, struct file_handle __user *uofh,
+				int newfd, const char __user *newname);
 #endif
-- 
1.7.0.4

[PATCH -V21 07/12] x86: Add new syscalls for x86_32

[Aneesh Kumar K.V]

This patch adds new syscalls to x86_32

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/x86/include/asm/unistd_32.h   |    7 ++++++-
 arch/x86/kernel/syscall_table_32.S |    5 +++++
 2 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
index b766a5e..6e4d5b5 100644
--- a/arch/x86/include/asm/unistd_32.h
+++ b/arch/x86/include/asm/unistd_32.h
@@ -346,10 +346,15 @@
 #define __NR_fanotify_init	338
 #define __NR_fanotify_mark	339
 #define __NR_prlimit64		340
+#define __NR_name_to_handle_at	341
+#define __NR_open_by_handle_at  342
+#define __NR_readlink_by_handle 343
+#define __NR_stat64_by_handle   344
+#define __NR_link_by_handle     345
 
 #ifdef __KERNEL__
 
-#define NR_syscalls 341
+#define NR_syscalls 346
 
 #define __ARCH_WANT_IPC_PARSE_VERSION
 #define __ARCH_WANT_OLD_READDIR
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index b35786d..17b3a03 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -340,3 +340,8 @@ ENTRY(sys_call_table)
 	.long sys_fanotify_init
 	.long sys_fanotify_mark
 	.long sys_prlimit64		/* 340 */
+	.long sys_name_to_handle_at
+	.long sys_open_by_handle_at
+	.long sys_handle_readlink
+	.long sys_handle_stat64
+	.long sys_handle_link		/* 345 */
-- 
1.7.0.4

[PATCH -V21 08/12] x86: Add new syscalls for x86_64

[Aneesh Kumar K.V]

This patch add new syscalls to x86_64

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/x86/ia32/ia32entry.S        |    5 +++++
 arch/x86/include/asm/unistd_64.h |   10 ++++++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 518bb99..4649908 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -851,4 +851,9 @@ ia32_sys_call_table:
 	.quad sys_fanotify_init
 	.quad sys32_fanotify_mark
 	.quad sys_prlimit64		/* 340 */
+	.quad sys_name_to_handle_at
+	.quad compat_sys_open_by_handle_at
+	.quad sys_handle_readlink
+	.quad sys32_handle_stat64
+	.quad sys_handle_link		/* 345 */
 ia32_syscall_end:
diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
index 363e9b8..4e13e76 100644
--- a/arch/x86/include/asm/unistd_64.h
+++ b/arch/x86/include/asm/unistd_64.h
@@ -669,6 +669,16 @@ __SYSCALL(__NR_fanotify_init, sys_fanotify_init)
 __SYSCALL(__NR_fanotify_mark, sys_fanotify_mark)
 #define __NR_prlimit64				302
 __SYSCALL(__NR_prlimit64, sys_prlimit64)
+#define __NR_name_to_handle_at			303
+__SYSCALL(__NR_name_to_handle_at, sys_name_to_handle_at)
+#define __NR_open_by_handle_at			304
+__SYSCALL(__NR_open_by_handle_at, sys_open_by_handle_at)
+#define __NR_readlink_by_handle			305
+__SYSCALL(__NR_readlink_by_handle, sys_handle_readlink)
+#define __NR_stat_by_handle			306
+__SYSCALL(__NR_stat_by_handle, sys_handle_stat)
+#define __NR_link_by_handle			307
+__SYSCALL(__NR_link_by_handle, sys_handle_link)
 
 #ifndef __NO_STUBS
 #define __ARCH_WANT_OLD_READDIR
-- 
1.7.0.4

[PATCH -V21 09/12] unistd.h: Add new syscalls numbers to asm-generic

[Aneesh Kumar K.V]

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 include/asm-generic/unistd.h |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/include/asm-generic/unistd.h b/include/asm-generic/unistd.h
index b969770..9469305 100644
--- a/include/asm-generic/unistd.h
+++ b/include/asm-generic/unistd.h
@@ -646,9 +646,19 @@ __SYSCALL(__NR_prlimit64, sys_prlimit64)
 __SYSCALL(__NR_fanotify_init, sys_fanotify_init)
 #define __NR_fanotify_mark 263
 __SYSCALL(__NR_fanotify_mark, sys_fanotify_mark)
+#define __NR_name_to_handle_at		264
+__SYSCALL(__NR_name_to_handle_at, sys_name_to_handle_at)
+#define __NR_open_by_handle_at		265
+__SYSCALL(__NR_open_by_handle_at, sys_open_by_handle_at)
+#define __NR_readlink_by_handle		266
+__SYSCALL(__NR_readlink_by_handle, sys_handle_readlink)
+#define __NR_stat64_by_handle		267
+__SYSCALL(__NR_stat64_by_handle, sys_handle_stat64)
+#define __NR_link_by_handle		268
+__SYSCALL(__NR_link_by_handle, sys_handle_link)
 
 #undef __NR_syscalls
-#define __NR_syscalls 264
+#define __NR_syscalls 269
 
 /*
  * All syscalls below here should go away really,
-- 
1.7.0.4

[PATCH -V21 10/12] vfs: Export file system uuid via /proc/<pid>/mountinfo

[Aneesh Kumar K.V]

We add a per superblock uuid field. File systems should
update the uuid in the fill_super callback

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/namespace.c     |   16 ++++++++++++++++
 include/linux/fs.h |    1 +
 2 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index a72eaab..27fd1b8 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -871,6 +871,18 @@ const struct seq_operations mounts_op = {
 	.show	= show_vfsmnt
 };
 
+static int uuid_is_nil(u8 *uuid)
+{
+	int i;
+	u8  *cp = (u8 *)uuid;
+
+	for (i = 0; i < 16; i++) {
+		if (*cp++)
+			return 0;
+	}
+	return 1;
+}
+
 static int show_mountinfo(struct seq_file *m, void *v)
 {
 	struct proc_mounts *p = m->private;
@@ -909,6 +921,10 @@ static int show_mountinfo(struct seq_file *m, void *v)
 	if (IS_MNT_UNBINDABLE(mnt))
 		seq_puts(m, " unbindable");
 
+	if (!uuid_is_nil(mnt->mnt_sb->s_uuid))
+		/* print the uuid */
+		seq_printf(m, " uuid:%pU", mnt->mnt_sb->s_uuid);
+
 	/* Filesystem specific data */
 	seq_puts(m, " - ");
 	show_type(m, sb);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cffe154..32ef678 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1367,6 +1367,7 @@ struct super_block {
 	wait_queue_head_t	s_wait_unfrozen;
 
 	char s_id[32];				/* Informational name */
+	u8 s_uuid[16];				/* UUID */
 
 	void 			*s_fs_info;	/* Filesystem private info */
 	fmode_t			s_mode;
-- 
1.7.0.4

[PATCH -V21 11/12] ext3: Copy fs UUID to superblock.

[Aneesh Kumar K.V]

File system UUID is made available to application
via  /proc/<pid>/mountinfo

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/ext3/super.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 5dbf4db..6dda322 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1918,6 +1918,7 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 	sb->s_qcop = &ext3_qctl_operations;
 	sb->dq_op = &ext3_quota_operations;
 #endif
+	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
 	mutex_init(&sbi->s_orphan_lock);
 	mutex_init(&sbi->s_resize_lock);
-- 
1.7.0.4

[PATCH -V21 12/12] ext4: Copy fs UUID to superblock

[Aneesh Kumar K.V]

File system UUID is made available to application
via  /proc/<pid>/mountinfo

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/ext4/super.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 2614774..b46a78c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2941,6 +2941,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_qcop = &ext4_qctl_operations;
 	sb->dq_op = &ext4_quota_operations;
 #endif
+	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
+
 	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
 	mutex_init(&sbi->s_orphan_lock);
 	mutex_init(&sbi->s_resize_lock);
-- 
1.7.0.4

Re: [PATCH -V21 00/12] Generic name to handle and open by handle syscalls

[J. Bruce Fields]

On Tue, Oct 05, 2010 at 03:52:08PM +0530, Aneesh Kumar K.V wrote:
> Hi,
> 
> The below set of patches implement open by handle support using exportfs
> operations. This allows user space application to map a file name to file
> handle and later open the file using handle. This should be usable
> for userspace NFS [1] and 9P server [2]. XFS already support this with the ioctls
> XFS_IOC_PATH_TO_HANDLE and XFS_IOC_OPEN_BY_HANDLE.
> 
> [1] http://nfs-ganesha.sourceforge.net/
> [2] http://thread.gmane.org/gmane.comp.emulators.qemu/68992
> 
> git repo for the patchset at:
> git://git.kernel.org/pub/scm/linux/kernel/git/kvaneesh/linux-open-handle.git open-by-handle
> 
> Test case can be found at
> http://git.kernel.org/?p=fs/ext2/kvaneesh/handle-test.git
> git://git.kernel.org/pub/scm/fs/ext2/kvaneesh/handle-test.git
> 
> Changes from V20:
> a) Use better variable names
> b) change handle_size type to __u32
> c) max handle size is now nfsv4 handle size. Considering file system would
>    want to support a handle that can fit into nfsv4 handle size limiting
>    max handle size to 128 rather than 4096 is the right thing.

Looks OK to me.

I haven't read the later patches carefully, but in general an interface
like this seems to me a useful thing to have.

--b.

> d) I didn't add Ceph changes in the series. I am expecting the changes
>    will go via Ceph tree.
> 
> -aneesh
> 

Re: [PATCH -V21 00/12] Generic name to handle and open by handle syscalls

[Aneesh Kumar K. V]

On Tue,  5 Oct 2010 15:52:08 +0530, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
> Hi,
> 
> The below set of patches implement open by handle support using exportfs
> operations. This allows user space application to map a file name to file
> handle and later open the file using handle. This should be usable
> for userspace NFS [1] and 9P server [2]. XFS already support this with the ioctls
> XFS_IOC_PATH_TO_HANDLE and XFS_IOC_OPEN_BY_HANDLE.
> 
> [1] http://nfs-ganesha.sourceforge.net/
> [2] http://thread.gmane.org/gmane.comp.emulators.qemu/68992
> 
> git repo for the patchset at:
> git://git.kernel.org/pub/scm/linux/kernel/git/kvaneesh/linux-open-handle.git open-by-handle
> 
> Test case can be found at
> http://git.kernel.org/?p=fs/ext2/kvaneesh/handle-test.git
> git://git.kernel.org/pub/scm/fs/ext2/kvaneesh/handle-test.git
> 
> Changes from V20:
> a) Use better variable names
> b) change handle_size type to __u32
> c) max handle size is now nfsv4 handle size. Considering file system would
>    want to support a handle that can fit into nfsv4 handle size limiting
>    max handle size to 128 rather than 4096 is the right thing.
> d) I didn't add Ceph changes in the series. I am expecting the changes
>    will go via Ceph tree.
> 

Hi Al,

Any update on this ? Can we get this merged in this merge window.

-aneesh