On Fri, 22 Jun 2012 01:51:46 +0200, Jan Kara [off-list ref] wrote:

On Thu 21-06-12 13:08:51, Dmitry Monakhov wrote:

quoted

* Abstract
  A subtree of a directory tree T is a tree consisting of a directory
  (the subtree root) in T and all of its descendants in T.

  *NOTE*: User is allowed to break pure subtree hierarchy via manual
          id manipulation.

  Project subtrees assumptions:
  (1) Each inode has an id. This id is persistently stored inside
      inode (xattr, usually inside ibody)
  (2) Project id is inherent from parent directory

  This feature is similar to project-id in XFS. One may assign some id to
  a subtree. Each entry from the subtree may be accounted in directory
  project quota. Will appear in later patches.

* Disk layout
  Project id is stored on disk inside xattr usually inside ibody.
  Xattr is used only as a data storage, It has not user visible xattr
  interface.

* User interface
  Project id is accessible via generic xattr interface "system.project_id"

* Notes
  ext4_setattr interface to prjid: Semantically prjid must being changed
  similar to uid/gid, but project_id is stored inside xattr so on-disk
  structures updates is not that trivial, so I've move prjid change
  logic to separate function.

  Generally, I like the patch. Some comments are below.

Also reasonable, will redo.

quoted

Signed-off-by: Dmitry Monakhov <redacted>
---
 fs/ext4/Kconfig   |    8 ++
 fs/ext4/Makefile  |    1 +
 fs/ext4/ext4.h    |    4 +
 fs/ext4/ialloc.c  |    6 ++
 fs/ext4/inode.c   |    4 +
 fs/ext4/project.c |  213 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/project.h |   45 +++++++++++
 fs/ext4/super.c   |   16 ++++
 fs/ext4/xattr.c   |    7 ++
 fs/ext4/xattr.h   |    2 +
 10 files changed, 306 insertions(+), 0 deletions(-)
 create mode 100644 fs/ext4/project.c
 create mode 100644 fs/ext4/project.h

diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index c22f170..377af40 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig

@@ -76,6 +76,14 @@ config EXT4_FS_SECURITY
 
 	  If you are not using a security module that requires using
 	  extended attributes for file security labels, say N.
+config EXT4_PROJECT_ID
+	bool "Ext4 project_id support"
+	depends on PROJECT_ID
+	depends on EXT4_FS_XATTR
+	help
+	  Enables project inode identifier support for ext4 filesystem.
+	  This feature allow to assign some id to inodes similar to
+	  uid/gid. 

  Is separate config option useful? The amount of code added for this is
not really big and there is not other speed / space benefit in disabling
this, is there?

quoted

 config EXT4_DEBUG
 	bool "EXT4 debugging support"

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 56fd8f8..692fe56 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile

@@ -12,3 +12,4 @@ ext4-y	:= balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
 ext4-$(CONFIG_EXT4_FS_XATTR)		+= xattr.o xattr_user.o xattr_trusted.o
 ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
 ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o
+ext4-$(CONFIG_EXT4_PROJECT_ID)		+= project.o

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index cfc4e01..c0e33d7 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h

@@ -925,6 +925,9 @@ struct ext4_inode_info {
 
 	/* Precomputed uuid+inum+igen checksum for seeding inode checksums */
 	__u32 i_csum_seed;
+#ifdef CONFIG_EXT4_PROJECT_ID
+	__u32 i_prjid;
+#endif
 };
 
 /*

@@ -962,6 +965,7 @@ struct ext4_inode_info {
 #define EXT4_MOUNT_POSIX_ACL		0x08000	/* POSIX Access Control Lists */
 #define EXT4_MOUNT_NO_AUTO_DA_ALLOC	0x10000	/* No auto delalloc mapping */
 #define EXT4_MOUNT_BARRIER		0x20000 /* Use block barriers */
+#define EXT4_MOUNT_PROJECT_ID		0x40000 /* project owner id support */

  And I would even question the necessity of the mount option. Can we make
the rule that no system.prjid xattr simply means prjid == 0. When someone
sets prjid, it gets further automatically inherited and everything works
fine. I don't see the need for special mount option for this - again no
significant overhead is introduced when we always check whether we should
inherit non-zero prjid... Thoughts?

Yep. this reasonable, Also it allows us to save mountopt bit space for
new crazy stuff. 

quoted

 #define EXT4_MOUNT_QUOTA		0x80000 /* Some quota option set */
 #define EXT4_MOUNT_USRQUOTA		0x100000 /* "old" user quota */
 #define EXT4_MOUNT_GRPQUOTA		0x200000 /* "old" group quota */

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index d48e8b1..d4b72e5 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c

@@ -28,6 +28,7 @@
 #include "ext4_jbd2.h"
 #include "xattr.h"
 #include "acl.h"
+#include "project.h"
 
 #include <trace/events/ext4.h>
 

@@ -898,6 +899,8 @@ got:
 
 	ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
 
+	ext4_setprjid(inode, ext4_getprjid(dir));
+
 	ret = inode;
 	dquot_initialize(inode);
 	err = dquot_alloc_inode(inode);

@@ -911,6 +914,9 @@ got:
 	err = ext4_init_security(handle, inode, dir, qstr);
 	if (err)
 		goto fail_free_drop;
+	err = ext4_prj_init(handle, inode);
+	if (err)
+		goto fail_free_drop;
 
 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
 		/* set extent flag only for directory, file and normal symlink*/

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 02bc8cb..c98d8d6 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c

@@ -42,6 +42,7 @@
 #include "xattr.h"
 #include "acl.h"
 #include "truncate.h"
+#include "project.h"
 
 #include <trace/events/ext4.h>
 

@@ -3870,6 +3871,9 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	if (ret)
 		goto bad_inode;
+	ret = ext4_prj_read(inode);
+	if (ret)
+		goto bad_inode;
 
 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = &ext4_file_inode_operations;

diff --git a/fs/ext4/project.c b/fs/ext4/project.c
new file mode 100644
index 0000000..a262a49
--- /dev/null
+++ b/fs/ext4/project.c

@@ -0,0 +1,213 @@
+/*
+ * linux/fs/ext4/projectid.c
+ *
+ * Copyright (C) 2010 Parallels Inc
+ * Dmitry Monakhov <dmonakhov@openvz.org>
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include "ext4_jbd2.h"
+#include "ext4.h"
+#include "xattr.h"
+#include "project.h"
+
+
+/*
+ * PROJECT SUBTREE
+ * A subtree of a directory tree T is a tree consisting of a directory
+ * (the subtree root) in T and all of its descendants in T.
+ *
+ * Project Subtree's assumptions:
+ * (1) Each inode has subtree id. This id is persistently stored inside
+ *     inode's xattr, usually inside ibody
+ * (2) Subtree id is inherent from parent directory
+ */
+
+/*
+ * Read project_id id from inode's xattr
+ * Locking: none
+ */
+int ext4_prj_xattr_read(struct inode *inode, unsigned int *prjid)
+{
+	__le32 dsk_prjid;
+	int retval;

  Please add empty line between declarations and function body... Also
holds for some functions below.

quoted

+	retval = ext4_xattr_get(inode, EXT4_XATTR_INDEX_PROJECT_ID, "",
+				&dsk_prjid, sizeof (dsk_prjid));
+	if (retval > 0) {
+		if (retval != sizeof(dsk_prjid))
+			return -EIO;
+		else
+			retval = 0;
+	}
+	*prjid = le32_to_cpu(dsk_prjid);
+	return retval;
+
+}

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR
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