[PATCH, RFC] - remove mounpoint UUID code

[PATCH, RFC] - remove mounpoint UUID code

[Eric Sandeen]

It looks like all of the below is unused... and according
to Nathan,

"dont think it even got used/implemented anywhere, but i think it 
was meant to be an auto-mount kinda thing... such that when you look 
up at that point, it knows to mount the device with that uuid there, 
if its not already it was never really written anywhere ... just an 
idea in doug doucettes brain i think."

Think it'll ever go anywhere, or should it get pruned?

The below builds; not at all tested, until I get an idea if it's worth
doing.  Need to double check that some structures might not need padding
out to keep things compatible/consistent...

 dmapi/xfs_dm.c    |    2 --
 xfs_attr_leaf.c   |    6 +-----
 xfs_bmap.c        |    4 ----
 xfs_dinode.h      |    2 --
 xfs_inode.c       |    8 --------
 xfs_inode.h       |    1 -
 xfs_inode_item.c  |   53 +++++++++++------------------------------------------
 xfs_inode_item.h  |   26 ++++++++------------------
 xfs_itable.c      |    2 --
 xfs_log_recover.c |   10 ++--------
 xfsidbg.c         |    2 +-
 11 files changed, 23 insertions(+), 93 deletions(-)


Index: linux-2.6-xfs/fs/xfs/dmapi/xfs_dm.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/dmapi/xfs_dm.c
+++ linux-2.6-xfs/fs/xfs/dmapi/xfs_dm.c
@@ -363,7 +363,6 @@ xfs_dip_to_stat(
 		buf->dt_blocks = 0;
 		break;
 	case XFS_DINODE_FMT_LOCAL:
-	case XFS_DINODE_FMT_UUID:
 		buf->dt_rdev = 0;
 		buf->dt_blksize = mp->m_sb.sb_blocksize;
 		buf->dt_blocks = 0;
@@ -431,7 +430,6 @@ xfs_ip_to_stat(
 		buf->dt_blocks = 0;
 		break;
 	case XFS_DINODE_FMT_LOCAL:
-	case XFS_DINODE_FMT_UUID:
 		buf->dt_rdev = 0;
 		buf->dt_blksize = mp->m_sb.sb_blocksize;
 		buf->dt_blocks = 0;
Index: linux-2.6-xfs/fs/xfs/xfs_attr_leaf.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_attr_leaf.c
+++ linux-2.6-xfs/fs/xfs/xfs_attr_leaf.c
@@ -155,13 +155,9 @@ xfs_attr_shortform_bytesfit(xfs_inode_t 
 
 	offset = (XFS_LITINO(mp) - bytes) >> 3; /* rounded down */
 
-	switch (dp->i_d.di_format) {
-	case XFS_DINODE_FMT_DEV:
+	if (dp->i_d.di_format == XFS_DINODE_FMT_DEV) {
 		minforkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
 		return (offset >= minforkoff) ? minforkoff : 0;
-	case XFS_DINODE_FMT_UUID:
-		minforkoff = roundup(sizeof(uuid_t), 8) >> 3;
-		return (offset >= minforkoff) ? minforkoff : 0;
 	}
 
 	if (!(mp->m_flags & XFS_MOUNT_ATTR2)) {
Index: linux-2.6-xfs/fs/xfs/xfs_bmap.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_bmap.c
+++ linux-2.6-xfs/fs/xfs/xfs_bmap.c
@@ -3532,7 +3532,6 @@ xfs_bmap_forkoff_reset(
 {
 	if (whichfork == XFS_ATTR_FORK &&
 	    (ip->i_d.di_format != XFS_DINODE_FMT_DEV) &&
-	    (ip->i_d.di_format != XFS_DINODE_FMT_UUID) &&
 	    (ip->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
 	    ((mp->m_attroffset >> 3) > ip->i_d.di_forkoff)) {
 		ip->i_d.di_forkoff = mp->m_attroffset >> 3;
@@ -4000,9 +3999,6 @@ xfs_bmap_add_attrfork(
 	case XFS_DINODE_FMT_DEV:
 		ip->i_d.di_forkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
 		break;
-	case XFS_DINODE_FMT_UUID:
-		ip->i_d.di_forkoff = roundup(sizeof(uuid_t), 8) >> 3;
-		break;
 	case XFS_DINODE_FMT_LOCAL:
 	case XFS_DINODE_FMT_EXTENTS:
 	case XFS_DINODE_FMT_BTREE:
Index: linux-2.6-xfs/fs/xfs/xfs_dinode.h
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_dinode.h
+++ linux-2.6-xfs/fs/xfs/xfs_dinode.h
@@ -88,7 +88,6 @@ typedef struct xfs_dinode
 		xfs_dir2_sf_t	di_dir2sf;	/* shortform directory v2 */
 		char		di_c[1];	/* local contents */
 		__be32		di_dev;		/* device for S_IFCHR/S_IFBLK */
-		uuid_t		di_muuid;	/* mount point value */
 		char		di_symlink[1];	/* local symbolic link */
 	}		di_u;
 	union {
@@ -150,7 +149,6 @@ typedef enum xfs_dinode_fmt
 					/* LNK: di_symlink */
 	XFS_DINODE_FMT_EXTENTS,		/* DIR, REG, LNK: di_bmx */
 	XFS_DINODE_FMT_BTREE,		/* DIR, REG, LNK: di_bmbt */
-	XFS_DINODE_FMT_UUID		/* MNT: di_uuid */
 } xfs_dinode_fmt_t;
 
 /*
Index: linux-2.6-xfs/fs/xfs/xfs_inode.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_inode.c
+++ linux-2.6-xfs/fs/xfs/xfs_inode.c
@@ -2970,14 +2970,6 @@ xfs_iflush_fork(
 		}
 		break;
 
-	case XFS_DINODE_FMT_UUID:
-		if (iip->ili_format.ilf_fields & XFS_ILOG_UUID) {
-			ASSERT(whichfork == XFS_DATA_FORK);
-			memcpy(&dip->di_u.di_muuid, &ip->i_df.if_u2.if_uuid,
-				sizeof(uuid_t));
-		}
-		break;
-
 	default:
 		ASSERT(0);
 		break;
Index: linux-2.6-xfs/fs/xfs/xfs_inode_item.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_inode_item.c
+++ linux-2.6-xfs/fs/xfs/xfs_inode_item.c
@@ -70,8 +70,7 @@ xfs_inode_item_size(
 	switch (ip->i_d.di_format) {
 	case XFS_DINODE_FMT_EXTENTS:
 		iip->ili_format.ilf_fields &=
-			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
-			  XFS_ILOG_DEV | XFS_ILOG_UUID);
+			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT | XFS_ILOG_DEV);
 		if ((iip->ili_format.ilf_fields & XFS_ILOG_DEXT) &&
 		    (ip->i_d.di_nextents > 0) &&
 		    (ip->i_df.if_bytes > 0)) {
@@ -86,8 +85,7 @@ xfs_inode_item_size(
 		ASSERT(ip->i_df.if_ext_max ==
 		       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
 		iip->ili_format.ilf_fields &=
-			~(XFS_ILOG_DDATA | XFS_ILOG_DEXT |
-			  XFS_ILOG_DEV | XFS_ILOG_UUID);
+			~(XFS_ILOG_DDATA | XFS_ILOG_DEXT | XFS_ILOG_DEV);
 		if ((iip->ili_format.ilf_fields & XFS_ILOG_DBROOT) &&
 		    (ip->i_df.if_broot_bytes > 0)) {
 			ASSERT(ip->i_df.if_broot != NULL);
@@ -112,8 +110,7 @@ xfs_inode_item_size(
 
 	case XFS_DINODE_FMT_LOCAL:
 		iip->ili_format.ilf_fields &=
-			~(XFS_ILOG_DEXT | XFS_ILOG_DBROOT |
-			  XFS_ILOG_DEV | XFS_ILOG_UUID);
+			~(XFS_ILOG_DEXT | XFS_ILOG_DBROOT | XFS_ILOG_DEV);
 		if ((iip->ili_format.ilf_fields & XFS_ILOG_DDATA) &&
 		    (ip->i_df.if_bytes > 0)) {
 			ASSERT(ip->i_df.if_u1.if_data != NULL);
@@ -126,14 +123,7 @@ xfs_inode_item_size(
 
 	case XFS_DINODE_FMT_DEV:
 		iip->ili_format.ilf_fields &=
-			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
-			  XFS_ILOG_DEXT | XFS_ILOG_UUID);
-		break;
-
-	case XFS_DINODE_FMT_UUID:
-		iip->ili_format.ilf_fields &=
-			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
-			  XFS_ILOG_DEXT | XFS_ILOG_DEV);
+			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT | XFS_ILOG_DEXT);
 		break;
 
 	default:
@@ -319,8 +309,7 @@ xfs_inode_item_format(
 	switch (ip->i_d.di_format) {
 	case XFS_DINODE_FMT_EXTENTS:
 		ASSERT(!(iip->ili_format.ilf_fields &
-			 (XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
-			  XFS_ILOG_DEV | XFS_ILOG_UUID)));
+			 (XFS_ILOG_DDATA | XFS_ILOG_DBROOT | XFS_ILOG_DEV)));
 		if (iip->ili_format.ilf_fields & XFS_ILOG_DEXT) {
 			ASSERT(ip->i_df.if_bytes > 0);
 			ASSERT(ip->i_df.if_u1.if_extents != NULL);
@@ -369,8 +358,7 @@ xfs_inode_item_format(
 
 	case XFS_DINODE_FMT_BTREE:
 		ASSERT(!(iip->ili_format.ilf_fields &
-			 (XFS_ILOG_DDATA | XFS_ILOG_DEXT |
-			  XFS_ILOG_DEV | XFS_ILOG_UUID)));
+			 (XFS_ILOG_DDATA | XFS_ILOG_DEXT | XFS_ILOG_DEV)));
 		if (iip->ili_format.ilf_fields & XFS_ILOG_DBROOT) {
 			ASSERT(ip->i_df.if_broot_bytes > 0);
 			ASSERT(ip->i_df.if_broot != NULL);
@@ -385,8 +373,7 @@ xfs_inode_item_format(
 
 	case XFS_DINODE_FMT_LOCAL:
 		ASSERT(!(iip->ili_format.ilf_fields &
-			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
-			  XFS_ILOG_DEV | XFS_ILOG_UUID)));
+			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT | XFS_ILOG_DEV)));
 		if (iip->ili_format.ilf_fields & XFS_ILOG_DDATA) {
 			ASSERT(ip->i_df.if_bytes > 0);
 			ASSERT(ip->i_df.if_u1.if_data != NULL);
@@ -411,21 +398,9 @@ xfs_inode_item_format(
 
 	case XFS_DINODE_FMT_DEV:
 		ASSERT(!(iip->ili_format.ilf_fields &
-			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
-			  XFS_ILOG_DDATA | XFS_ILOG_UUID)));
+			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT | XFS_ILOG_DDATA)));
 		if (iip->ili_format.ilf_fields & XFS_ILOG_DEV) {
-			iip->ili_format.ilf_u.ilfu_rdev =
-				ip->i_df.if_u2.if_rdev;
-		}
-		break;
-
-	case XFS_DINODE_FMT_UUID:
-		ASSERT(!(iip->ili_format.ilf_fields &
-			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
-			  XFS_ILOG_DDATA | XFS_ILOG_DEV)));
-		if (iip->ili_format.ilf_fields & XFS_ILOG_UUID) {
-			iip->ili_format.ilf_u.ilfu_uuid =
-				ip->i_df.if_u2.if_uuid;
+			iip->ili_format.ilf_rdev = ip->i_df.if_u2.if_rdev;
 		}
 		break;
 
@@ -1088,10 +1063,7 @@ xfs_inode_item_format_convert(
 		in_f->ilf_asize = in_f32->ilf_asize;
 		in_f->ilf_dsize = in_f32->ilf_dsize;
 		in_f->ilf_ino = in_f32->ilf_ino;
-		/* copy biggest field of ilf_u */
-		memcpy(in_f->ilf_u.ilfu_uuid.__u_bits,
-		       in_f32->ilf_u.ilfu_uuid.__u_bits,
-		       sizeof(uuid_t));
+		in_f->ilf_rdev = in_f32->ilf_rdev;
 		in_f->ilf_blkno = in_f32->ilf_blkno;
 		in_f->ilf_len = in_f32->ilf_len;
 		in_f->ilf_boffset = in_f32->ilf_boffset;
@@ -1106,10 +1078,7 @@ xfs_inode_item_format_convert(
 		in_f->ilf_asize = in_f64->ilf_asize;
 		in_f->ilf_dsize = in_f64->ilf_dsize;
 		in_f->ilf_ino = in_f64->ilf_ino;
-		/* copy biggest field of ilf_u */
-		memcpy(in_f->ilf_u.ilfu_uuid.__u_bits,
-		       in_f64->ilf_u.ilfu_uuid.__u_bits,
-		       sizeof(uuid_t));
+		in_f->ilf_rdev = in_f64->ilf_rdev;
 		in_f->ilf_blkno = in_f64->ilf_blkno;
 		in_f->ilf_len = in_f64->ilf_len;
 		in_f->ilf_boffset = in_f64->ilf_boffset;
Index: linux-2.6-xfs/fs/xfs/xfs_itable.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_itable.c
+++ linux-2.6-xfs/fs/xfs/xfs_itable.c
@@ -111,7 +111,6 @@ xfs_bulkstat_one_iget(
 		buf->bs_blocks = 0;
 		break;
 	case XFS_DINODE_FMT_LOCAL:
-	case XFS_DINODE_FMT_UUID:
 		buf->bs_rdev = 0;
 		buf->bs_blksize = mp->m_sb.sb_blocksize;
 		buf->bs_blocks = 0;
@@ -186,7 +185,6 @@ xfs_bulkstat_one_dinode(
 		buf->bs_blocks = 0;
 		break;
 	case XFS_DINODE_FMT_LOCAL:
-	case XFS_DINODE_FMT_UUID:
 		buf->bs_rdev = 0;
 		buf->bs_blksize = mp->m_sb.sb_blocksize;
 		buf->bs_blocks = 0;
Index: linux-2.6-xfs/fs/xfs/xfs_inode_item.h
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_inode_item.h
+++ linux-2.6-xfs/fs/xfs/xfs_inode_item.h
@@ -31,10 +31,7 @@ typedef struct xfs_inode_log_format {
 	__uint16_t		ilf_asize;	/* size of attr d/ext/root */
 	__uint16_t		ilf_dsize;	/* size of data/ext/root */
 	__uint64_t		ilf_ino;	/* inode number */
-	union {
-		__uint32_t	ilfu_rdev;	/* rdev value for dev inode*/
-		uuid_t		ilfu_uuid;	/* mount point value */
-	} ilf_u;
+	__uint32_t		ilf_rdev;	/* rdev value for dev inode*/
 	__int64_t		ilf_blkno;	/* blkno of inode buffer */
 	__int32_t		ilf_len;	/* len of inode buffer */
 	__int32_t		ilf_boffset;	/* off of inode in buffer */
@@ -48,10 +45,7 @@ typedef struct xfs_inode_log_format_32 {
 	__uint16_t		ilf_asize;	/* size of attr d/ext/root */
 	__uint16_t		ilf_dsize;	/* size of data/ext/root */
 	__uint64_t		ilf_ino;	/* inode number */
-	union {
-		__uint32_t	ilfu_rdev;	/* rdev value for dev inode*/
-		uuid_t		ilfu_uuid;	/* mount point value */
-	} ilf_u;
+	__uint32_t		ilf_rdev;	/* rdev value for dev inode*/
 	__int64_t		ilf_blkno;	/* blkno of inode buffer */
 	__int32_t		ilf_len;	/* len of inode buffer */
 	__int32_t		ilf_boffset;	/* off of inode in buffer */
@@ -66,10 +60,7 @@ typedef struct xfs_inode_log_format_64 {
 	__uint16_t		ilf_dsize;	/* size of data/ext/root */
 	__uint32_t		ilf_pad;	/* pad for 64 bit boundary */
 	__uint64_t		ilf_ino;	/* inode number */
-	union {
-		__uint32_t	ilfu_rdev;	/* rdev value for dev inode*/
-		uuid_t		ilfu_uuid;	/* mount point value */
-	} ilf_u;
+	__uint32_t		ilf_rdev;	/* rdev value for dev inode*/
 	__int64_t		ilf_blkno;	/* blkno of inode buffer */
 	__int32_t		ilf_len;	/* len of inode buffer */
 	__int32_t		ilf_boffset;	/* off of inode in buffer */
@@ -83,15 +74,15 @@ typedef struct xfs_inode_log_format_64 {
 #define	XFS_ILOG_DEXT	0x004	/* log i_df.if_extents */
 #define	XFS_ILOG_DBROOT	0x008	/* log i_df.i_broot */
 #define	XFS_ILOG_DEV	0x010	/* log the dev field */
-#define	XFS_ILOG_UUID	0x020	/* log the uuid field */
+/*			0x020*/ /* unused */
 #define	XFS_ILOG_ADATA	0x040	/* log i_af.if_data */
 #define	XFS_ILOG_AEXT	0x080	/* log i_af.if_extents */
 #define	XFS_ILOG_ABROOT	0x100	/* log i_af.i_broot */
 
 #define	XFS_ILOG_NONCORE	(XFS_ILOG_DDATA | XFS_ILOG_DEXT | \
 				 XFS_ILOG_DBROOT | XFS_ILOG_DEV | \
-				 XFS_ILOG_UUID | XFS_ILOG_ADATA | \
-				 XFS_ILOG_AEXT | XFS_ILOG_ABROOT)
+				 XFS_ILOG_ADATA | XFS_ILOG_AEXT | \
+				 XFS_ILOG_ABROOT)
 
 #define	XFS_ILOG_DFORK		(XFS_ILOG_DDATA | XFS_ILOG_DEXT | \
 				 XFS_ILOG_DBROOT)
@@ -101,9 +92,8 @@ typedef struct xfs_inode_log_format_64 {
 
 #define	XFS_ILOG_ALL		(XFS_ILOG_CORE | XFS_ILOG_DDATA | \
 				 XFS_ILOG_DEXT | XFS_ILOG_DBROOT | \
-				 XFS_ILOG_DEV | XFS_ILOG_UUID | \
-				 XFS_ILOG_ADATA | XFS_ILOG_AEXT | \
-				 XFS_ILOG_ABROOT)
+				 XFS_ILOG_DEV | XFS_ILOG_ADATA | \
+				 XFS_ILOG_AEXT | XFS_ILOG_ABROOT)
 
 #define	XFS_ILI_HOLD		0x1
 #define	XFS_ILI_IOLOCKED_EXCL	0x2
Index: linux-2.6-xfs/fs/xfs/xfs_log_recover.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_log_recover.c
+++ linux-2.6-xfs/fs/xfs/xfs_log_recover.c
@@ -2420,14 +2420,8 @@ xlog_recover_do_inode_trans(
 	}
 
 	fields = in_f->ilf_fields;
-	switch (fields & (XFS_ILOG_DEV | XFS_ILOG_UUID)) {
-	case XFS_ILOG_DEV:
-		dip->di_u.di_dev = cpu_to_be32(in_f->ilf_u.ilfu_rdev);
-		break;
-	case XFS_ILOG_UUID:
-		dip->di_u.di_muuid = in_f->ilf_u.ilfu_uuid;
-		break;
-	}
+	if (fields & XFS_ILOG_DEV)
+		dip->di_u.di_dev = cpu_to_be32(in_f->ilf_rdev);
 
 	if (in_f->ilf_size == 2)
 		goto write_inode_buffer;
Index: linux-2.6-xfs/fs/xfs/xfsidbg.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfsidbg.c
+++ linux-2.6-xfs/fs/xfs/xfsidbg.c
@@ -3424,7 +3424,7 @@ xfs_inode_item_print(xfs_inode_log_item_
 	kdb_printf("dsize %d, asize %d, rdev 0x%x\n",
 		ilip->ili_format.ilf_dsize,
 		ilip->ili_format.ilf_asize,
-		ilip->ili_format.ilf_u.ilfu_rdev);
+		ilip->ili_format.ilf_rdev);
 	kdb_printf("blkno 0x%Lx len 0x%x boffset 0x%x\n",
 		ilip->ili_format.ilf_blkno,
 		ilip->ili_format.ilf_len,
Index: linux-2.6-xfs/fs/xfs/xfs_inode.h
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_inode.h
+++ linux-2.6-xfs/fs/xfs/xfs_inode.h
@@ -79,7 +79,6 @@ typedef struct xfs_ifork {
 		char		if_inline_data[XFS_INLINE_DATA];
 						/* very small file data */
 		xfs_dev_t	if_rdev;	/* dev number if special */
-		uuid_t		if_uuid;	/* mount point value */
 	} if_u2;
 } xfs_ifork_t;
 

Re: [PATCH, RFC] - remove mounpoint UUID code

[Ian Costello]

CXFS does use this to mount filesystems, i.e. on a client read the sb 
get the uuid and use the uuid to lookup the MDS to request the mount...

Having said that if it is removed then it will force us to look at 
another method to mount a cxfs filesystem, and also remove the necessity 
for cxfs clients to not read the superblock (which is the only metadata 
cxfs clients read off disk at this point)...

Regards,

-- 
Ian Costello   Phone: +61 3 9963 1952
R&D Engineer   Mobile: +61 417 508 522
CXFS MultiOS


Eric Sandeen wrote:
> It looks like all of the below is unused... and according
> to Nathan,
> 
> "dont think it even got used/implemented anywhere, but i think it 
> was meant to be an auto-mount kinda thing... such that when you look 
> up at that point, it knows to mount the device with that uuid there, 
> if its not already it was never really written anywhere ... just an 
> idea in doug doucettes brain i think."
> 
> Think it'll ever go anywhere, or should it get pruned?
> 
> The below builds; not at all tested, until I get an idea if it's worth
> doing.  Need to double check that some structures might not need padding
> out to keep things compatible/consistent...
> 
>  dmapi/xfs_dm.c    |    2 --
>  xfs_attr_leaf.c   |    6 +-----
>  xfs_bmap.c        |    4 ----
>  xfs_dinode.h      |    2 --
>  xfs_inode.c       |    8 --------
>  xfs_inode.h       |    1 -
>  xfs_inode_item.c  |   53 +++++++++++------------------------------------------
>  xfs_inode_item.h  |   26 ++++++++------------------
>  xfs_itable.c      |    2 --
>  xfs_log_recover.c |   10 ++--------
>  xfsidbg.c         |    2 +-
>  11 files changed, 23 insertions(+), 93 deletions(-)
> 
> 
> Index: linux-2.6-xfs/fs/xfs/dmapi/xfs_dm.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/dmapi/xfs_dm.c
> +++ linux-2.6-xfs/fs/xfs/dmapi/xfs_dm.c
> @@ -363,7 +363,6 @@ xfs_dip_to_stat(
>  		buf->dt_blocks = 0;
>  		break;
>  	case XFS_DINODE_FMT_LOCAL:
> -	case XFS_DINODE_FMT_UUID:
>  		buf->dt_rdev = 0;
>  		buf->dt_blksize = mp->m_sb.sb_blocksize;
>  		buf->dt_blocks = 0;
> @@ -431,7 +430,6 @@ xfs_ip_to_stat(
>  		buf->dt_blocks = 0;
>  		break;
>  	case XFS_DINODE_FMT_LOCAL:
> -	case XFS_DINODE_FMT_UUID:
>  		buf->dt_rdev = 0;
>  		buf->dt_blksize = mp->m_sb.sb_blocksize;
>  		buf->dt_blocks = 0;
> Index: linux-2.6-xfs/fs/xfs/xfs_attr_leaf.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_attr_leaf.c
> +++ linux-2.6-xfs/fs/xfs/xfs_attr_leaf.c
> @@ -155,13 +155,9 @@ xfs_attr_shortform_bytesfit(xfs_inode_t 
>  
>  	offset = (XFS_LITINO(mp) - bytes) >> 3; /* rounded down */
>  
> -	switch (dp->i_d.di_format) {
> -	case XFS_DINODE_FMT_DEV:
> +	if (dp->i_d.di_format == XFS_DINODE_FMT_DEV) {
>  		minforkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
>  		return (offset >= minforkoff) ? minforkoff : 0;
> -	case XFS_DINODE_FMT_UUID:
> -		minforkoff = roundup(sizeof(uuid_t), 8) >> 3;
> -		return (offset >= minforkoff) ? minforkoff : 0;
>  	}
>  
>  	if (!(mp->m_flags & XFS_MOUNT_ATTR2)) {
> Index: linux-2.6-xfs/fs/xfs/xfs_bmap.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_bmap.c
> +++ linux-2.6-xfs/fs/xfs/xfs_bmap.c
> @@ -3532,7 +3532,6 @@ xfs_bmap_forkoff_reset(
>  {
>  	if (whichfork == XFS_ATTR_FORK &&
>  	    (ip->i_d.di_format != XFS_DINODE_FMT_DEV) &&
> -	    (ip->i_d.di_format != XFS_DINODE_FMT_UUID) &&
>  	    (ip->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
>  	    ((mp->m_attroffset >> 3) > ip->i_d.di_forkoff)) {
>  		ip->i_d.di_forkoff = mp->m_attroffset >> 3;
> @@ -4000,9 +3999,6 @@ xfs_bmap_add_attrfork(
>  	case XFS_DINODE_FMT_DEV:
>  		ip->i_d.di_forkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
>  		break;
> -	case XFS_DINODE_FMT_UUID:
> -		ip->i_d.di_forkoff = roundup(sizeof(uuid_t), 8) >> 3;
> -		break;
>  	case XFS_DINODE_FMT_LOCAL:
>  	case XFS_DINODE_FMT_EXTENTS:
>  	case XFS_DINODE_FMT_BTREE:
> Index: linux-2.6-xfs/fs/xfs/xfs_dinode.h
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_dinode.h
> +++ linux-2.6-xfs/fs/xfs/xfs_dinode.h
> @@ -88,7 +88,6 @@ typedef struct xfs_dinode
>  		xfs_dir2_sf_t	di_dir2sf;	/* shortform directory v2 */
>  		char		di_c[1];	/* local contents */
>  		__be32		di_dev;		/* device for S_IFCHR/S_IFBLK */
> -		uuid_t		di_muuid;	/* mount point value */
>  		char		di_symlink[1];	/* local symbolic link */
>  	}		di_u;
>  	union {
> @@ -150,7 +149,6 @@ typedef enum xfs_dinode_fmt
>  					/* LNK: di_symlink */
>  	XFS_DINODE_FMT_EXTENTS,		/* DIR, REG, LNK: di_bmx */
>  	XFS_DINODE_FMT_BTREE,		/* DIR, REG, LNK: di_bmbt */
> -	XFS_DINODE_FMT_UUID		/* MNT: di_uuid */
>  } xfs_dinode_fmt_t;
>  
>  /*
> Index: linux-2.6-xfs/fs/xfs/xfs_inode.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_inode.c
> +++ linux-2.6-xfs/fs/xfs/xfs_inode.c
> @@ -2970,14 +2970,6 @@ xfs_iflush_fork(
>  		}
>  		break;
>  
> -	case XFS_DINODE_FMT_UUID:
> -		if (iip->ili_format.ilf_fields & XFS_ILOG_UUID) {
> -			ASSERT(whichfork == XFS_DATA_FORK);
> -			memcpy(&dip->di_u.di_muuid, &ip->i_df.if_u2.if_uuid,
> -				sizeof(uuid_t));
> -		}
> -		break;
> -
>  	default:
>  		ASSERT(0);
>  		break;
> Index: linux-2.6-xfs/fs/xfs/xfs_inode_item.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_inode_item.c
> +++ linux-2.6-xfs/fs/xfs/xfs_inode_item.c
> @@ -70,8 +70,7 @@ xfs_inode_item_size(
>  	switch (ip->i_d.di_format) {
>  	case XFS_DINODE_FMT_EXTENTS:
>  		iip->ili_format.ilf_fields &=
> -			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
> -			  XFS_ILOG_DEV | XFS_ILOG_UUID);
> +			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT | XFS_ILOG_DEV);
>  		if ((iip->ili_format.ilf_fields & XFS_ILOG_DEXT) &&
>  		    (ip->i_d.di_nextents > 0) &&
>  		    (ip->i_df.if_bytes > 0)) {
> @@ -86,8 +85,7 @@ xfs_inode_item_size(
>  		ASSERT(ip->i_df.if_ext_max ==
>  		       XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t));
>  		iip->ili_format.ilf_fields &=
> -			~(XFS_ILOG_DDATA | XFS_ILOG_DEXT |
> -			  XFS_ILOG_DEV | XFS_ILOG_UUID);
> +			~(XFS_ILOG_DDATA | XFS_ILOG_DEXT | XFS_ILOG_DEV);
>  		if ((iip->ili_format.ilf_fields & XFS_ILOG_DBROOT) &&
>  		    (ip->i_df.if_broot_bytes > 0)) {
>  			ASSERT(ip->i_df.if_broot != NULL);
> @@ -112,8 +110,7 @@ xfs_inode_item_size(
>  
>  	case XFS_DINODE_FMT_LOCAL:
>  		iip->ili_format.ilf_fields &=
> -			~(XFS_ILOG_DEXT | XFS_ILOG_DBROOT |
> -			  XFS_ILOG_DEV | XFS_ILOG_UUID);
> +			~(XFS_ILOG_DEXT | XFS_ILOG_DBROOT | XFS_ILOG_DEV);
>  		if ((iip->ili_format.ilf_fields & XFS_ILOG_DDATA) &&
>  		    (ip->i_df.if_bytes > 0)) {
>  			ASSERT(ip->i_df.if_u1.if_data != NULL);
> @@ -126,14 +123,7 @@ xfs_inode_item_size(
>  
>  	case XFS_DINODE_FMT_DEV:
>  		iip->ili_format.ilf_fields &=
> -			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
> -			  XFS_ILOG_DEXT | XFS_ILOG_UUID);
> -		break;
> -
> -	case XFS_DINODE_FMT_UUID:
> -		iip->ili_format.ilf_fields &=
> -			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
> -			  XFS_ILOG_DEXT | XFS_ILOG_DEV);
> +			~(XFS_ILOG_DDATA | XFS_ILOG_DBROOT | XFS_ILOG_DEXT);
>  		break;
>  
>  	default:
> @@ -319,8 +309,7 @@ xfs_inode_item_format(
>  	switch (ip->i_d.di_format) {
>  	case XFS_DINODE_FMT_EXTENTS:
>  		ASSERT(!(iip->ili_format.ilf_fields &
> -			 (XFS_ILOG_DDATA | XFS_ILOG_DBROOT |
> -			  XFS_ILOG_DEV | XFS_ILOG_UUID)));
> +			 (XFS_ILOG_DDATA | XFS_ILOG_DBROOT | XFS_ILOG_DEV)));
>  		if (iip->ili_format.ilf_fields & XFS_ILOG_DEXT) {
>  			ASSERT(ip->i_df.if_bytes > 0);
>  			ASSERT(ip->i_df.if_u1.if_extents != NULL);
> @@ -369,8 +358,7 @@ xfs_inode_item_format(
>  
>  	case XFS_DINODE_FMT_BTREE:
>  		ASSERT(!(iip->ili_format.ilf_fields &
> -			 (XFS_ILOG_DDATA | XFS_ILOG_DEXT |
> -			  XFS_ILOG_DEV | XFS_ILOG_UUID)));
> +			 (XFS_ILOG_DDATA | XFS_ILOG_DEXT | XFS_ILOG_DEV)));
>  		if (iip->ili_format.ilf_fields & XFS_ILOG_DBROOT) {
>  			ASSERT(ip->i_df.if_broot_bytes > 0);
>  			ASSERT(ip->i_df.if_broot != NULL);
> @@ -385,8 +373,7 @@ xfs_inode_item_format(
>  
>  	case XFS_DINODE_FMT_LOCAL:
>  		ASSERT(!(iip->ili_format.ilf_fields &
> -			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
> -			  XFS_ILOG_DEV | XFS_ILOG_UUID)));
> +			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT | XFS_ILOG_DEV)));
>  		if (iip->ili_format.ilf_fields & XFS_ILOG_DDATA) {
>  			ASSERT(ip->i_df.if_bytes > 0);
>  			ASSERT(ip->i_df.if_u1.if_data != NULL);
> @@ -411,21 +398,9 @@ xfs_inode_item_format(
>  
>  	case XFS_DINODE_FMT_DEV:
>  		ASSERT(!(iip->ili_format.ilf_fields &
> -			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
> -			  XFS_ILOG_DDATA | XFS_ILOG_UUID)));
> +			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT | XFS_ILOG_DDATA)));
>  		if (iip->ili_format.ilf_fields & XFS_ILOG_DEV) {
> -			iip->ili_format.ilf_u.ilfu_rdev =
> -				ip->i_df.if_u2.if_rdev;
> -		}
> -		break;
> -
> -	case XFS_DINODE_FMT_UUID:
> -		ASSERT(!(iip->ili_format.ilf_fields &
> -			 (XFS_ILOG_DBROOT | XFS_ILOG_DEXT |
> -			  XFS_ILOG_DDATA | XFS_ILOG_DEV)));
> -		if (iip->ili_format.ilf_fields & XFS_ILOG_UUID) {
> -			iip->ili_format.ilf_u.ilfu_uuid =
> -				ip->i_df.if_u2.if_uuid;
> +			iip->ili_format.ilf_rdev = ip->i_df.if_u2.if_rdev;
>  		}
>  		break;
>  
> @@ -1088,10 +1063,7 @@ xfs_inode_item_format_convert(
>  		in_f->ilf_asize = in_f32->ilf_asize;
>  		in_f->ilf_dsize = in_f32->ilf_dsize;
>  		in_f->ilf_ino = in_f32->ilf_ino;
> -		/* copy biggest field of ilf_u */
> -		memcpy(in_f->ilf_u.ilfu_uuid.__u_bits,
> -		       in_f32->ilf_u.ilfu_uuid.__u_bits,
> -		       sizeof(uuid_t));
> +		in_f->ilf_rdev = in_f32->ilf_rdev;
>  		in_f->ilf_blkno = in_f32->ilf_blkno;
>  		in_f->ilf_len = in_f32->ilf_len;
>  		in_f->ilf_boffset = in_f32->ilf_boffset;
> @@ -1106,10 +1078,7 @@ xfs_inode_item_format_convert(
>  		in_f->ilf_asize = in_f64->ilf_asize;
>  		in_f->ilf_dsize = in_f64->ilf_dsize;
>  		in_f->ilf_ino = in_f64->ilf_ino;
> -		/* copy biggest field of ilf_u */
> -		memcpy(in_f->ilf_u.ilfu_uuid.__u_bits,
> -		       in_f64->ilf_u.ilfu_uuid.__u_bits,
> -		       sizeof(uuid_t));
> +		in_f->ilf_rdev = in_f64->ilf_rdev;
>  		in_f->ilf_blkno = in_f64->ilf_blkno;
>  		in_f->ilf_len = in_f64->ilf_len;
>  		in_f->ilf_boffset = in_f64->ilf_boffset;
> Index: linux-2.6-xfs/fs/xfs/xfs_itable.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_itable.c
> +++ linux-2.6-xfs/fs/xfs/xfs_itable.c
> @@ -111,7 +111,6 @@ xfs_bulkstat_one_iget(
>  		buf->bs_blocks = 0;
>  		break;
>  	case XFS_DINODE_FMT_LOCAL:
> -	case XFS_DINODE_FMT_UUID:
>  		buf->bs_rdev = 0;
>  		buf->bs_blksize = mp->m_sb.sb_blocksize;
>  		buf->bs_blocks = 0;
> @@ -186,7 +185,6 @@ xfs_bulkstat_one_dinode(
>  		buf->bs_blocks = 0;
>  		break;
>  	case XFS_DINODE_FMT_LOCAL:
> -	case XFS_DINODE_FMT_UUID:
>  		buf->bs_rdev = 0;
>  		buf->bs_blksize = mp->m_sb.sb_blocksize;
>  		buf->bs_blocks = 0;
> Index: linux-2.6-xfs/fs/xfs/xfs_inode_item.h
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_inode_item.h
> +++ linux-2.6-xfs/fs/xfs/xfs_inode_item.h
> @@ -31,10 +31,7 @@ typedef struct xfs_inode_log_format {
>  	__uint16_t		ilf_asize;	/* size of attr d/ext/root */
>  	__uint16_t		ilf_dsize;	/* size of data/ext/root */
>  	__uint64_t		ilf_ino;	/* inode number */
> -	union {
> -		__uint32_t	ilfu_rdev;	/* rdev value for dev inode*/
> -		uuid_t		ilfu_uuid;	/* mount point value */
> -	} ilf_u;
> +	__uint32_t		ilf_rdev;	/* rdev value for dev inode*/
>  	__int64_t		ilf_blkno;	/* blkno of inode buffer */
>  	__int32_t		ilf_len;	/* len of inode buffer */
>  	__int32_t		ilf_boffset;	/* off of inode in buffer */
> @@ -48,10 +45,7 @@ typedef struct xfs_inode_log_format_32 {
>  	__uint16_t		ilf_asize;	/* size of attr d/ext/root */
>  	__uint16_t		ilf_dsize;	/* size of data/ext/root */
>  	__uint64_t		ilf_ino;	/* inode number */
> -	union {
> -		__uint32_t	ilfu_rdev;	/* rdev value for dev inode*/
> -		uuid_t		ilfu_uuid;	/* mount point value */
> -	} ilf_u;
> +	__uint32_t		ilf_rdev;	/* rdev value for dev inode*/
>  	__int64_t		ilf_blkno;	/* blkno of inode buffer */
>  	__int32_t		ilf_len;	/* len of inode buffer */
>  	__int32_t		ilf_boffset;	/* off of inode in buffer */
> @@ -66,10 +60,7 @@ typedef struct xfs_inode_log_format_64 {
>  	__uint16_t		ilf_dsize;	/* size of data/ext/root */
>  	__uint32_t		ilf_pad;	/* pad for 64 bit boundary */
>  	__uint64_t		ilf_ino;	/* inode number */
> -	union {
> -		__uint32_t	ilfu_rdev;	/* rdev value for dev inode*/
> -		uuid_t		ilfu_uuid;	/* mount point value */
> -	} ilf_u;
> +	__uint32_t		ilf_rdev;	/* rdev value for dev inode*/
>  	__int64_t		ilf_blkno;	/* blkno of inode buffer */
>  	__int32_t		ilf_len;	/* len of inode buffer */
>  	__int32_t		ilf_boffset;	/* off of inode in buffer */
> @@ -83,15 +74,15 @@ typedef struct xfs_inode_log_format_64 {
>  #define	XFS_ILOG_DEXT	0x004	/* log i_df.if_extents */
>  #define	XFS_ILOG_DBROOT	0x008	/* log i_df.i_broot */
>  #define	XFS_ILOG_DEV	0x010	/* log the dev field */
> -#define	XFS_ILOG_UUID	0x020	/* log the uuid field */
> +/*			0x020*/ /* unused */
>  #define	XFS_ILOG_ADATA	0x040	/* log i_af.if_data */
>  #define	XFS_ILOG_AEXT	0x080	/* log i_af.if_extents */
>  #define	XFS_ILOG_ABROOT	0x100	/* log i_af.i_broot */
>  
>  #define	XFS_ILOG_NONCORE	(XFS_ILOG_DDATA | XFS_ILOG_DEXT | \
>  				 XFS_ILOG_DBROOT | XFS_ILOG_DEV | \
> -				 XFS_ILOG_UUID | XFS_ILOG_ADATA | \
> -				 XFS_ILOG_AEXT | XFS_ILOG_ABROOT)
> +				 XFS_ILOG_ADATA | XFS_ILOG_AEXT | \
> +				 XFS_ILOG_ABROOT)
>  
>  #define	XFS_ILOG_DFORK		(XFS_ILOG_DDATA | XFS_ILOG_DEXT | \
>  				 XFS_ILOG_DBROOT)
> @@ -101,9 +92,8 @@ typedef struct xfs_inode_log_format_64 {
>  
>  #define	XFS_ILOG_ALL		(XFS_ILOG_CORE | XFS_ILOG_DDATA | \
>  				 XFS_ILOG_DEXT | XFS_ILOG_DBROOT | \
> -				 XFS_ILOG_DEV | XFS_ILOG_UUID | \
> -				 XFS_ILOG_ADATA | XFS_ILOG_AEXT | \
> -				 XFS_ILOG_ABROOT)
> +				 XFS_ILOG_DEV | XFS_ILOG_ADATA | \
> +				 XFS_ILOG_AEXT | XFS_ILOG_ABROOT)
>  
>  #define	XFS_ILI_HOLD		0x1
>  #define	XFS_ILI_IOLOCKED_EXCL	0x2
> Index: linux-2.6-xfs/fs/xfs/xfs_log_recover.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_log_recover.c
> +++ linux-2.6-xfs/fs/xfs/xfs_log_recover.c
> @@ -2420,14 +2420,8 @@ xlog_recover_do_inode_trans(
>  	}
>  
>  	fields = in_f->ilf_fields;
> -	switch (fields & (XFS_ILOG_DEV | XFS_ILOG_UUID)) {
> -	case XFS_ILOG_DEV:
> -		dip->di_u.di_dev = cpu_to_be32(in_f->ilf_u.ilfu_rdev);
> -		break;
> -	case XFS_ILOG_UUID:
> -		dip->di_u.di_muuid = in_f->ilf_u.ilfu_uuid;
> -		break;
> -	}
> +	if (fields & XFS_ILOG_DEV)
> +		dip->di_u.di_dev = cpu_to_be32(in_f->ilf_rdev);
>  
>  	if (in_f->ilf_size == 2)
>  		goto write_inode_buffer;
> Index: linux-2.6-xfs/fs/xfs/xfsidbg.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfsidbg.c
> +++ linux-2.6-xfs/fs/xfs/xfsidbg.c
> @@ -3424,7 +3424,7 @@ xfs_inode_item_print(xfs_inode_log_item_
>  	kdb_printf("dsize %d, asize %d, rdev 0x%x\n",
>  		ilip->ili_format.ilf_dsize,
>  		ilip->ili_format.ilf_asize,
> -		ilip->ili_format.ilf_u.ilfu_rdev);
> +		ilip->ili_format.ilf_rdev);
>  	kdb_printf("blkno 0x%Lx len 0x%x boffset 0x%x\n",
>  		ilip->ili_format.ilf_blkno,
>  		ilip->ili_format.ilf_len,
> Index: linux-2.6-xfs/fs/xfs/xfs_inode.h
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/xfs_inode.h
> +++ linux-2.6-xfs/fs/xfs/xfs_inode.h
> @@ -79,7 +79,6 @@ typedef struct xfs_ifork {
>  		char		if_inline_data[XFS_INLINE_DATA];
>  						/* very small file data */
>  		xfs_dev_t	if_rdev;	/* dev number if special */
> -		uuid_t		if_uuid;	/* mount point value */
>  	} if_u2;
>  } xfs_ifork_t;
>  
> 
> 
> 
> 

Re: [PATCH, RFC] - remove mounpoint UUID code

[Eric Sandeen]

Ian Costello wrote:
> CXFS does use this to mount filesystems, i.e. on a client read the sb 
> get the uuid and use the uuid to lookup the MDS to request the mount...

Well, this isn't removing the sb uuid... it's this special file type
XFS_DINODE_FMT_UUID... which is cxfs using?

-Eric

> Having said that if it is removed then it will force us to look at 
> another method to mount a cxfs filesystem, and also remove the necessity 
> for cxfs clients to not read the superblock (which is the only metadata 
> cxfs clients read off disk at this point)...
> 
> Regards,
> 

Re: [PATCH, RFC] - remove mounpoint UUID code

[Ian Costello]

Eric,

My bad, cxfs uses the sb_uuid, should have looked a little closer at the 
patch. I assumed the worst from the heading (must have filtered the 
"point" out of the heading :)

Eric Sandeen wrote:
> Ian Costello wrote:
>> CXFS does use this to mount filesystems, i.e. on a client read the sb 
>> get the uuid and use the uuid to lookup the MDS to request the mount...
> 
> Well, this isn't removing the sb uuid... it's this special file type
> XFS_DINODE_FMT_UUID... which is cxfs using?
> 
> -Eric
> 
>> Having said that if it is removed then it will force us to look at 
>> another method to mount a cxfs filesystem, and also remove the necessity 
>> for cxfs clients to not read the superblock (which is the only metadata 
>> cxfs clients read off disk at this point)...
>>
>> Regards,
>>
> 
> 

Thanks,

-- 
Ian Costello   Phone: +61 3 9963 1952
R&D Engineer   Mobile: +61 417 508 522
CXFS MultiOS

Re: [PATCH, RFC] - remove mounpoint UUID code

[Eric Sandeen]

Ian Costello wrote:
> Eric,
> 
> My bad, cxfs uses the sb_uuid, should have looked a little closer at the 
> patch. I assumed the worst from the heading (must have filtered the 
> "point" out of the heading :)

Nah, I wouldn't do that to you ;)

(and you wouldn't have to accept it if I did try!)  :)

-Eric

Re: [PATCH, RFC] - remove mounpoint UUID code

[Christoph Hellwig]

On Fri, Mar 07, 2008 at 10:00:56PM -0600, Eric Sandeen wrote:
> It looks like all of the below is unused... and according
> to Nathan,
> 
> "dont think it even got used/implemented anywhere, but i think it 
> was meant to be an auto-mount kinda thing... such that when you look 
> up at that point, it knows to mount the device with that uuid there, 
> if its not already it was never really written anywhere ... just an 
> idea in doug doucettes brain i think."
> 
> Think it'll ever go anywhere, or should it get pruned?
> 
> The below builds; not at all tested, until I get an idea if it's worth
> doing.  Need to double check that some structures might not need padding
> out to keep things compatible/consistent...

This looks fine to me.  But please keep the XFS_DINODE_FMT_UUID enum
value and add a big comment close to it documenting what it was an maybe
a approximate removal date so people who care about it can look it up
in the SCM history easily.

Re: [PATCH, RFC] - remove mounpoint UUID code

[Nathan Scott]

On Fri, 2008-03-07 at 22:00 -0600, Eric Sandeen wrote:
> It looks like all of the below is unused... and according
> to Nathan,
> 
> "dont think it even got used/implemented anywhere, but i think it 
> was meant to be an auto-mount kinda thing... such that when you look 
> up at that point, it knows to mount the device with that uuid there, 
> if its not already it was never really written anywhere ... just an 
> idea in doug doucettes brain i think."
> 
> Think it'll ever go anywhere, or should it get pruned?
> 
> The below builds; not at all tested, until I get an idea if it's worth
> doing.  Need to double check that some structures might not need padding
> out to keep things compatible/consistent...

Since effectively all versions of XFS support this feature ondisk,
including complete support in recovery, it would be better IMO to
leave it in for someone to implement/experiment with the syscall
and auto-mounting userspace support.  That would then require no
new feature bits, mkfs/repair changes, etc.  There is effectively
zero cost to leaving it there - and non-zero cost in removing it,
if our seriously bad regression-via-cleanup history is anything
to go by ... :|

It would be really unfortunate to remove this, and then find that
it was useful to someone (who didn't know about it at this time).
OTOH, if there is definately never ever any chance this can ever
be useful, then it should indeed be removed. :)

cheers.

-- 
Nathan

Re: [PATCH, RFC] - remove mounpoint UUID code

[Eric Sandeen]

Nathan Scott wrote:


(hope you didn't too much mind my quoting you in this thread) ;)

> Since effectively all versions of XFS support this feature ondisk,
> including complete support in recovery, it would be better IMO to
> leave it in for someone to implement/experiment with the syscall
> and auto-mounting userspace support.  That would then require no
> new feature bits, mkfs/repair changes, etc.  There is effectively
> zero cost to leaving it there - and non-zero cost in removing it,
> if our seriously bad regression-via-cleanup history is anything
> to go by ... :|

the only cost to leaving it is having another instance of "ok now what
the heck is THIS?!" ... death by a thousand cuts of xfs complexity.  But
yeah, removing it has some risk too.

> It would be really unfortunate to remove this, and then find that
> it was useful to someone (who didn't know about it at this time).
> OTOH, if there is definately never ever any chance this can ever
> be useful, then it should indeed be removed. :)

Well I'm not hung up about it.  If anyone thinks it'll be useful, I'm
not bothered by leaving it as is.  So, Nathan, what are your plans for
this code? *grin*

-Eric

Re: [PATCH, RFC] - remove mounpoint UUID code

[nscott]

> Nathan Scott wrote:
>
>
> (hope you didn't too much mind my quoting you in this thread) ;)

(hope you didn't mind too much my dissing your cleanup) :)

>> Since effectively all versions of XFS support this feature ondisk,
>> including complete support in recovery, it would be better IMO to
>> leave it in for someone to implement/experiment with the syscall
>> and auto-mounting userspace support.  That would then require no
>> new feature bits, mkfs/repair changes, etc.  There is effectively
>> zero cost to leaving it there - and non-zero cost in removing it,
>> if our seriously bad regression-via-cleanup history is anything
>> to go by ... :|
>
> the only cost to leaving it is having another instance of "ok now what
> the heck is THIS?!" ... death by a thousand cuts of xfs complexity.  But
> yeah, removing it has some risk too.

So, document it and move on.  It would be a fun little project to go and
experiment with this code a bit.  It amounts to a trivial amount of code
at the end of the day, and theres certainly nothing "complex" about it.

>> It would be really unfortunate to remove this, and then find that
>> it was useful to someone (who didn't know about it at this time).
>> OTOH, if there is definately never ever any chance this can ever
>> be useful, then it should indeed be removed. :)
>
> Well I'm not hung up about it.  If anyone thinks it'll be useful, I'm
> not bothered by leaving it as is.  So, Nathan, what are your plans for
> this code? *grin*

I don't have any immediate plans.  I can imagine it could be used to
stitch parts of the namespace together in a filesystem that supports
multiple devices (in a chunkfs kinda way) ... or maybe more simply
just an in-filesystem auto-mounter.  *shrug*.  But its there, the tools
support it (once again, I didn't see a userspace patch - hohum), so I
would vote for leaving it in its current form so some enterprising,
constructive young coder can try to make something useful from it
at some point.  :)

cheers.

Re: [PATCH, RFC] - remove mounpoint UUID code

[Christoph Hellwig]

On Wed, Mar 12, 2008 at 07:09:56AM +1100, nscott@aconex.com wrote:
> I don't have any immediate plans.  I can imagine it could be used to
> stitch parts of the namespace together in a filesystem that supports
> multiple devices (in a chunkfs kinda way) ... or maybe more simply
> just an in-filesystem auto-mounter.  *shrug*.  But its there, the tools
> support it (once again, I didn't see a userspace patch - hohum), so I
> would vote for leaving it in its current form so some enterprising,
> constructive young coder can try to make something useful from it
> at some point.  :)

That kind of automounter really doesn't belong into the low-level
filesystem.  If we really wanted it it would go into the VFS, storing
the uuid or other identifier for the mountpoint in an xattr.  This is
really just dead junk that should go away.

Re: [PATCH, RFC] - remove mountpoint UUID code

[Eric Sandeen]

Christoph Hellwig wrote:
> On Wed, Mar 12, 2008 at 07:09:56AM +1100, nscott@aconex.com wrote:
>> I don't have any immediate plans.  I can imagine it could be used to
>> stitch parts of the namespace together in a filesystem that supports
>> multiple devices (in a chunkfs kinda way) ... or maybe more simply
>> just an in-filesystem auto-mounter.  *shrug*.  But its there, the tools
>> support it (once again, I didn't see a userspace patch - hohum), so I
>> would vote for leaving it in its current form so some enterprising,
>> constructive young coder can try to make something useful from it
>> at some point.  :)
> 
> That kind of automounter really doesn't belong into the low-level
> filesystem.  If we really wanted it it would go into the VFS, storing
> the uuid or other identifier for the mountpoint in an xattr.  This is
> really just dead junk that should go away.

Can I get a yea or nay on this from sgi, then?

Thanks,
-Eric

Re: [PATCH, RFC] - remove mounpoint UUID code

[Niv Sardi]

ACK, removing it, it should be trivial to put back in if we ever need it.
-- 
Niv Sardi

Re: [PATCH, RFC] - remove mounpoint UUID code

[Eric Sandeen]

Niv Sardi wrote:
> ACK, removing it, it should be trivial to put back in if we ever need it.

Ok, hch had some comments and this needs a careful eye towards any
affected disk structures so probably should not go in immediately as-is.

-Eric

Re: [PATCH, RFC] - remove mounpoint UUID code

[Niv Sardi]

Eric Sandeen <sandeen@sandeen.net> writes:

> Niv Sardi wrote:
>> ACK, removing it, it should be trivial to put back in if we ever need it.
>
> Ok, hch had some comments and this needs a careful eye towards any
> affected disk structures so probably should not go in immediately as-is.

Yeah, just saw that, well it's only in -dev now, so we'll audit it
carefully, and see where it goes.

I only read hch's last comment which ended in «This is really just dead
junk that should go away.».

Anyway, we now can use the awesome xfsqa infrastructure to have this
tested =)

Cheers,
-- 
Niv Sardi