2005-04-16 22:20:36 +00:00
|
|
|
/*
|
2005-11-02 03:58:39 +00:00
|
|
|
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
|
|
|
|
|
* All Rights Reserved.
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
2005-11-02 03:58:39 +00:00
|
|
|
* This program is free software; you can redistribute it and/or
|
|
|
|
|
* modify it under the terms of the GNU General Public License as
|
2005-04-16 22:20:36 +00:00
|
|
|
* published by the Free Software Foundation.
|
|
|
|
|
*
|
2005-11-02 03:58:39 +00:00
|
|
|
* This program is distributed in the hope that it would be useful,
|
|
|
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
|
|
* GNU General Public License for more details.
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
2005-11-02 03:58:39 +00:00
|
|
|
* You should have received a copy of the GNU General Public License
|
|
|
|
|
* along with this program; if not, write the Free Software Foundation,
|
|
|
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
|
|
|
|
#ifndef __XFS_SB_H__
|
|
|
|
|
#define __XFS_SB_H__
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Super block
|
|
|
|
|
* Fits into a sector-sized buffer at address 0 of each allocation group.
|
|
|
|
|
* Only the first of these is ever updated except during growfs.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
struct xfs_buf;
|
|
|
|
|
struct xfs_mount;
|
|
|
|
|
|
|
|
|
|
#define XFS_SB_MAGIC 0x58465342 /* 'XFSB' */
|
|
|
|
|
#define XFS_SB_VERSION_1 1 /* 5.3, 6.0.1, 6.1 */
|
|
|
|
|
#define XFS_SB_VERSION_2 2 /* 6.2 - attributes */
|
|
|
|
|
#define XFS_SB_VERSION_3 3 /* 6.2 - new inode version */
|
|
|
|
|
#define XFS_SB_VERSION_4 4 /* 6.2+ - bitmask version */
|
|
|
|
|
#define XFS_SB_VERSION_NUMBITS 0x000f
|
|
|
|
|
#define XFS_SB_VERSION_ALLFBITS 0xfff0
|
|
|
|
|
#define XFS_SB_VERSION_SASHFBITS 0xf000
|
|
|
|
|
#define XFS_SB_VERSION_REALFBITS 0x0ff0
|
|
|
|
|
#define XFS_SB_VERSION_ATTRBIT 0x0010
|
|
|
|
|
#define XFS_SB_VERSION_NLINKBIT 0x0020
|
|
|
|
|
#define XFS_SB_VERSION_QUOTABIT 0x0040
|
|
|
|
|
#define XFS_SB_VERSION_ALIGNBIT 0x0080
|
|
|
|
|
#define XFS_SB_VERSION_DALIGNBIT 0x0100
|
|
|
|
|
#define XFS_SB_VERSION_SHAREDBIT 0x0200
|
|
|
|
|
#define XFS_SB_VERSION_LOGV2BIT 0x0400
|
|
|
|
|
#define XFS_SB_VERSION_SECTORBIT 0x0800
|
|
|
|
|
#define XFS_SB_VERSION_EXTFLGBIT 0x1000
|
|
|
|
|
#define XFS_SB_VERSION_DIRV2BIT 0x2000
|
2008-05-21 06:58:55 +00:00
|
|
|
#define XFS_SB_VERSION_BORGBIT 0x4000 /* ASCII only case-insens. */
|
2005-04-16 22:20:36 +00:00
|
|
|
#define XFS_SB_VERSION_MOREBITSBIT 0x8000
|
|
|
|
|
#define XFS_SB_VERSION_OKSASHFBITS \
|
|
|
|
|
(XFS_SB_VERSION_EXTFLGBIT | \
|
2008-05-21 06:58:55 +00:00
|
|
|
XFS_SB_VERSION_DIRV2BIT | \
|
|
|
|
|
XFS_SB_VERSION_BORGBIT)
|
2005-04-16 22:20:36 +00:00
|
|
|
#define XFS_SB_VERSION_OKREALFBITS \
|
|
|
|
|
(XFS_SB_VERSION_ATTRBIT | \
|
|
|
|
|
XFS_SB_VERSION_NLINKBIT | \
|
|
|
|
|
XFS_SB_VERSION_QUOTABIT | \
|
|
|
|
|
XFS_SB_VERSION_ALIGNBIT | \
|
|
|
|
|
XFS_SB_VERSION_DALIGNBIT | \
|
|
|
|
|
XFS_SB_VERSION_SHAREDBIT | \
|
|
|
|
|
XFS_SB_VERSION_LOGV2BIT | \
|
2005-11-01 23:34:53 +00:00
|
|
|
XFS_SB_VERSION_SECTORBIT | \
|
|
|
|
|
XFS_SB_VERSION_MOREBITSBIT)
|
2005-04-16 22:20:36 +00:00
|
|
|
#define XFS_SB_VERSION_OKREALBITS \
|
|
|
|
|
(XFS_SB_VERSION_NUMBITS | \
|
|
|
|
|
XFS_SB_VERSION_OKREALFBITS | \
|
|
|
|
|
XFS_SB_VERSION_OKSASHFBITS)
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* There are two words to hold XFS "feature" bits: the original
|
|
|
|
|
* word, sb_versionnum, and sb_features2. Whenever a bit is set in
|
|
|
|
|
* sb_features2, the feature bit XFS_SB_VERSION_MOREBITSBIT must be set.
|
|
|
|
|
*
|
|
|
|
|
* These defines represent bits in sb_features2.
|
|
|
|
|
*/
|
|
|
|
|
#define XFS_SB_VERSION2_REALFBITS 0x00ffffff /* Mask: features */
|
|
|
|
|
#define XFS_SB_VERSION2_RESERVED1BIT 0x00000001
|
[XFS] Lazy Superblock Counters
When we have a couple of hundred transactions on the fly at once, they all
typically modify the on disk superblock in some way.
create/unclink/mkdir/rmdir modify inode counts, allocation/freeing modify
free block counts.
When these counts are modified in a transaction, they must eventually lock
the superblock buffer and apply the mods. The buffer then remains locked
until the transaction is committed into the incore log buffer. The result
of this is that with enough transactions on the fly the incore superblock
buffer becomes a bottleneck.
The result of contention on the incore superblock buffer is that
transaction rates fall - the more pressure that is put on the superblock
buffer, the slower things go.
The key to removing the contention is to not require the superblock fields
in question to be locked. We do that by not marking the superblock dirty
in the transaction. IOWs, we modify the incore superblock but do not
modify the cached superblock buffer. In short, we do not log superblock
modifications to critical fields in the superblock on every transaction.
In fact we only do it just before we write the superblock to disk every
sync period or just before unmount.
This creates an interesting problem - if we don't log or write out the
fields in every transaction, then how do the values get recovered after a
crash? the answer is simple - we keep enough duplicate, logged information
in other structures that we can reconstruct the correct count after log
recovery has been performed.
It is the AGF and AGI structures that contain the duplicate information;
after recovery, we walk every AGI and AGF and sum their individual
counters to get the correct value, and we do a transaction into the log to
correct them. An optimisation of this is that if we have a clean unmount
record, we know the value in the superblock is correct, so we can avoid
the summation walk under normal conditions and so mount/recovery times do
not change under normal operation.
One wrinkle that was discovered during development was that the blocks
used in the freespace btrees are never accounted for in the AGF counters.
This was once a valid optimisation to make; when the filesystem is full,
the free space btrees are empty and consume no space. Hence when it
matters, the "accounting" is correct. But that means the when we do the
AGF summations, we would not have a correct count and xfs_check would
complain. Hence a new counter was added to track the number of blocks used
by the free space btrees. This is an *on-disk format change*.
As a result of this, lazy superblock counters are a mkfs option and at the
moment on linux there is no way to convert an old filesystem. This is
possible - xfs_db can be used to twiddle the right bits and then
xfs_repair will do the format conversion for you. Similarly, you can
convert backwards as well. At some point we'll add functionality to
xfs_admin to do the bit twiddling easily....
SGI-PV: 964999
SGI-Modid: xfs-linux-melb:xfs-kern:28652a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-24 05:26:31 +00:00
|
|
|
#define XFS_SB_VERSION2_LAZYSBCOUNTBIT 0x00000002 /* Superblk counters */
|
2005-11-01 23:34:53 +00:00
|
|
|
#define XFS_SB_VERSION2_RESERVED4BIT 0x00000004
|
|
|
|
|
#define XFS_SB_VERSION2_ATTR2BIT 0x00000008 /* Inline attr rework */
|
2008-12-09 09:47:32 +00:00
|
|
|
#define XFS_SB_VERSION2_PARENTBIT 0x00000010 /* parent pointers */
|
2010-09-26 06:10:18 +00:00
|
|
|
#define XFS_SB_VERSION2_PROJID32BIT 0x00000080 /* 32 bit project id */
|
2012-11-15 22:20:37 +00:00
|
|
|
#define XFS_SB_VERSION2_CRCBIT 0x00000100 /* metadata CRCs */
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
|
#define XFS_SB_VERSION2_OKREALFBITS \
|
[XFS] Lazy Superblock Counters
When we have a couple of hundred transactions on the fly at once, they all
typically modify the on disk superblock in some way.
create/unclink/mkdir/rmdir modify inode counts, allocation/freeing modify
free block counts.
When these counts are modified in a transaction, they must eventually lock
the superblock buffer and apply the mods. The buffer then remains locked
until the transaction is committed into the incore log buffer. The result
of this is that with enough transactions on the fly the incore superblock
buffer becomes a bottleneck.
The result of contention on the incore superblock buffer is that
transaction rates fall - the more pressure that is put on the superblock
buffer, the slower things go.
The key to removing the contention is to not require the superblock fields
in question to be locked. We do that by not marking the superblock dirty
in the transaction. IOWs, we modify the incore superblock but do not
modify the cached superblock buffer. In short, we do not log superblock
modifications to critical fields in the superblock on every transaction.
In fact we only do it just before we write the superblock to disk every
sync period or just before unmount.
This creates an interesting problem - if we don't log or write out the
fields in every transaction, then how do the values get recovered after a
crash? the answer is simple - we keep enough duplicate, logged information
in other structures that we can reconstruct the correct count after log
recovery has been performed.
It is the AGF and AGI structures that contain the duplicate information;
after recovery, we walk every AGI and AGF and sum their individual
counters to get the correct value, and we do a transaction into the log to
correct them. An optimisation of this is that if we have a clean unmount
record, we know the value in the superblock is correct, so we can avoid
the summation walk under normal conditions and so mount/recovery times do
not change under normal operation.
One wrinkle that was discovered during development was that the blocks
used in the freespace btrees are never accounted for in the AGF counters.
This was once a valid optimisation to make; when the filesystem is full,
the free space btrees are empty and consume no space. Hence when it
matters, the "accounting" is correct. But that means the when we do the
AGF summations, we would not have a correct count and xfs_check would
complain. Hence a new counter was added to track the number of blocks used
by the free space btrees. This is an *on-disk format change*.
As a result of this, lazy superblock counters are a mkfs option and at the
moment on linux there is no way to convert an old filesystem. This is
possible - xfs_db can be used to twiddle the right bits and then
xfs_repair will do the format conversion for you. Similarly, you can
convert backwards as well. At some point we'll add functionality to
xfs_admin to do the bit twiddling easily....
SGI-PV: 964999
SGI-Modid: xfs-linux-melb:xfs-kern:28652a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-24 05:26:31 +00:00
|
|
|
(XFS_SB_VERSION2_LAZYSBCOUNTBIT | \
|
2010-09-26 06:10:18 +00:00
|
|
|
XFS_SB_VERSION2_ATTR2BIT | \
|
|
|
|
|
XFS_SB_VERSION2_PROJID32BIT)
|
2005-04-16 22:20:36 +00:00
|
|
|
#define XFS_SB_VERSION2_OKSASHFBITS \
|
|
|
|
|
(0)
|
|
|
|
|
#define XFS_SB_VERSION2_OKREALBITS \
|
|
|
|
|
(XFS_SB_VERSION2_OKREALFBITS | \
|
|
|
|
|
XFS_SB_VERSION2_OKSASHFBITS )
|
|
|
|
|
|
2007-08-28 03:58:06 +00:00
|
|
|
/*
|
|
|
|
|
* Superblock - in core version. Must match the ondisk version below.
|
2008-03-06 02:45:50 +00:00
|
|
|
* Must be padded to 64 bit alignment.
|
2007-08-28 03:58:06 +00:00
|
|
|
*/
|
|
|
|
|
typedef struct xfs_sb {
|
2005-04-16 22:20:36 +00:00
|
|
|
__uint32_t sb_magicnum; /* magic number == XFS_SB_MAGIC */
|
|
|
|
|
__uint32_t sb_blocksize; /* logical block size, bytes */
|
|
|
|
|
xfs_drfsbno_t sb_dblocks; /* number of data blocks */
|
|
|
|
|
xfs_drfsbno_t sb_rblocks; /* number of realtime blocks */
|
|
|
|
|
xfs_drtbno_t sb_rextents; /* number of realtime extents */
|
|
|
|
|
uuid_t sb_uuid; /* file system unique id */
|
|
|
|
|
xfs_dfsbno_t sb_logstart; /* starting block of log if internal */
|
|
|
|
|
xfs_ino_t sb_rootino; /* root inode number */
|
|
|
|
|
xfs_ino_t sb_rbmino; /* bitmap inode for realtime extents */
|
|
|
|
|
xfs_ino_t sb_rsumino; /* summary inode for rt bitmap */
|
|
|
|
|
xfs_agblock_t sb_rextsize; /* realtime extent size, blocks */
|
|
|
|
|
xfs_agblock_t sb_agblocks; /* size of an allocation group */
|
|
|
|
|
xfs_agnumber_t sb_agcount; /* number of allocation groups */
|
|
|
|
|
xfs_extlen_t sb_rbmblocks; /* number of rt bitmap blocks */
|
|
|
|
|
xfs_extlen_t sb_logblocks; /* number of log blocks */
|
|
|
|
|
__uint16_t sb_versionnum; /* header version == XFS_SB_VERSION */
|
|
|
|
|
__uint16_t sb_sectsize; /* volume sector size, bytes */
|
|
|
|
|
__uint16_t sb_inodesize; /* inode size, bytes */
|
|
|
|
|
__uint16_t sb_inopblock; /* inodes per block */
|
|
|
|
|
char sb_fname[12]; /* file system name */
|
|
|
|
|
__uint8_t sb_blocklog; /* log2 of sb_blocksize */
|
|
|
|
|
__uint8_t sb_sectlog; /* log2 of sb_sectsize */
|
|
|
|
|
__uint8_t sb_inodelog; /* log2 of sb_inodesize */
|
|
|
|
|
__uint8_t sb_inopblog; /* log2 of sb_inopblock */
|
|
|
|
|
__uint8_t sb_agblklog; /* log2 of sb_agblocks (rounded up) */
|
|
|
|
|
__uint8_t sb_rextslog; /* log2 of sb_rextents */
|
|
|
|
|
__uint8_t sb_inprogress; /* mkfs is in progress, don't mount */
|
|
|
|
|
__uint8_t sb_imax_pct; /* max % of fs for inode space */
|
|
|
|
|
/* statistics */
|
|
|
|
|
/*
|
|
|
|
|
* These fields must remain contiguous. If you really
|
|
|
|
|
* want to change their layout, make sure you fix the
|
|
|
|
|
* code in xfs_trans_apply_sb_deltas().
|
|
|
|
|
*/
|
|
|
|
|
__uint64_t sb_icount; /* allocated inodes */
|
|
|
|
|
__uint64_t sb_ifree; /* free inodes */
|
|
|
|
|
__uint64_t sb_fdblocks; /* free data blocks */
|
|
|
|
|
__uint64_t sb_frextents; /* free realtime extents */
|
|
|
|
|
/*
|
|
|
|
|
* End contiguous fields.
|
|
|
|
|
*/
|
|
|
|
|
xfs_ino_t sb_uquotino; /* user quota inode */
|
|
|
|
|
xfs_ino_t sb_gquotino; /* group quota inode */
|
|
|
|
|
__uint16_t sb_qflags; /* quota flags */
|
|
|
|
|
__uint8_t sb_flags; /* misc. flags */
|
|
|
|
|
__uint8_t sb_shared_vn; /* shared version number */
|
|
|
|
|
xfs_extlen_t sb_inoalignmt; /* inode chunk alignment, fsblocks */
|
|
|
|
|
__uint32_t sb_unit; /* stripe or raid unit */
|
|
|
|
|
__uint32_t sb_width; /* stripe or raid width */
|
|
|
|
|
__uint8_t sb_dirblklog; /* log2 of dir block size (fsbs) */
|
|
|
|
|
__uint8_t sb_logsectlog; /* log2 of the log sector size */
|
|
|
|
|
__uint16_t sb_logsectsize; /* sector size for the log, bytes */
|
|
|
|
|
__uint32_t sb_logsunit; /* stripe unit size for the log */
|
2005-11-01 23:34:53 +00:00
|
|
|
__uint32_t sb_features2; /* additional feature bits */
|
2008-03-06 02:45:50 +00:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* bad features2 field as a result of failing to pad the sb
|
|
|
|
|
* structure to 64 bits. Some machines will be using this field
|
|
|
|
|
* for features2 bits. Easiest just to mark it bad and not use
|
|
|
|
|
* it for anything else.
|
|
|
|
|
*/
|
|
|
|
|
__uint32_t sb_bad_features2;
|
|
|
|
|
|
|
|
|
|
/* must be padded to 64 bit alignment */
|
2005-04-16 22:20:36 +00:00
|
|
|
} xfs_sb_t;
|
|
|
|
|
|
2007-08-28 03:58:06 +00:00
|
|
|
/*
|
2008-03-06 02:45:50 +00:00
|
|
|
* Superblock - on disk version. Must match the in core version above.
|
|
|
|
|
* Must be padded to 64 bit alignment.
|
2007-08-28 03:58:06 +00:00
|
|
|
*/
|
|
|
|
|
typedef struct xfs_dsb {
|
|
|
|
|
__be32 sb_magicnum; /* magic number == XFS_SB_MAGIC */
|
|
|
|
|
__be32 sb_blocksize; /* logical block size, bytes */
|
|
|
|
|
__be64 sb_dblocks; /* number of data blocks */
|
|
|
|
|
__be64 sb_rblocks; /* number of realtime blocks */
|
|
|
|
|
__be64 sb_rextents; /* number of realtime extents */
|
|
|
|
|
uuid_t sb_uuid; /* file system unique id */
|
|
|
|
|
__be64 sb_logstart; /* starting block of log if internal */
|
|
|
|
|
__be64 sb_rootino; /* root inode number */
|
|
|
|
|
__be64 sb_rbmino; /* bitmap inode for realtime extents */
|
|
|
|
|
__be64 sb_rsumino; /* summary inode for rt bitmap */
|
|
|
|
|
__be32 sb_rextsize; /* realtime extent size, blocks */
|
|
|
|
|
__be32 sb_agblocks; /* size of an allocation group */
|
|
|
|
|
__be32 sb_agcount; /* number of allocation groups */
|
|
|
|
|
__be32 sb_rbmblocks; /* number of rt bitmap blocks */
|
|
|
|
|
__be32 sb_logblocks; /* number of log blocks */
|
|
|
|
|
__be16 sb_versionnum; /* header version == XFS_SB_VERSION */
|
|
|
|
|
__be16 sb_sectsize; /* volume sector size, bytes */
|
|
|
|
|
__be16 sb_inodesize; /* inode size, bytes */
|
|
|
|
|
__be16 sb_inopblock; /* inodes per block */
|
|
|
|
|
char sb_fname[12]; /* file system name */
|
|
|
|
|
__u8 sb_blocklog; /* log2 of sb_blocksize */
|
|
|
|
|
__u8 sb_sectlog; /* log2 of sb_sectsize */
|
|
|
|
|
__u8 sb_inodelog; /* log2 of sb_inodesize */
|
|
|
|
|
__u8 sb_inopblog; /* log2 of sb_inopblock */
|
|
|
|
|
__u8 sb_agblklog; /* log2 of sb_agblocks (rounded up) */
|
|
|
|
|
__u8 sb_rextslog; /* log2 of sb_rextents */
|
|
|
|
|
__u8 sb_inprogress; /* mkfs is in progress, don't mount */
|
|
|
|
|
__u8 sb_imax_pct; /* max % of fs for inode space */
|
|
|
|
|
/* statistics */
|
|
|
|
|
/*
|
|
|
|
|
* These fields must remain contiguous. If you really
|
|
|
|
|
* want to change their layout, make sure you fix the
|
|
|
|
|
* code in xfs_trans_apply_sb_deltas().
|
|
|
|
|
*/
|
|
|
|
|
__be64 sb_icount; /* allocated inodes */
|
|
|
|
|
__be64 sb_ifree; /* free inodes */
|
|
|
|
|
__be64 sb_fdblocks; /* free data blocks */
|
|
|
|
|
__be64 sb_frextents; /* free realtime extents */
|
|
|
|
|
/*
|
|
|
|
|
* End contiguous fields.
|
|
|
|
|
*/
|
|
|
|
|
__be64 sb_uquotino; /* user quota inode */
|
|
|
|
|
__be64 sb_gquotino; /* group quota inode */
|
|
|
|
|
__be16 sb_qflags; /* quota flags */
|
|
|
|
|
__u8 sb_flags; /* misc. flags */
|
|
|
|
|
__u8 sb_shared_vn; /* shared version number */
|
|
|
|
|
__be32 sb_inoalignmt; /* inode chunk alignment, fsblocks */
|
|
|
|
|
__be32 sb_unit; /* stripe or raid unit */
|
|
|
|
|
__be32 sb_width; /* stripe or raid width */
|
|
|
|
|
__u8 sb_dirblklog; /* log2 of dir block size (fsbs) */
|
|
|
|
|
__u8 sb_logsectlog; /* log2 of the log sector size */
|
|
|
|
|
__be16 sb_logsectsize; /* sector size for the log, bytes */
|
|
|
|
|
__be32 sb_logsunit; /* stripe unit size for the log */
|
|
|
|
|
__be32 sb_features2; /* additional feature bits */
|
2008-03-06 02:45:50 +00:00
|
|
|
/*
|
|
|
|
|
* bad features2 field as a result of failing to pad the sb
|
|
|
|
|
* structure to 64 bits. Some machines will be using this field
|
|
|
|
|
* for features2 bits. Easiest just to mark it bad and not use
|
|
|
|
|
* it for anything else.
|
|
|
|
|
*/
|
|
|
|
|
__be32 sb_bad_features2;
|
|
|
|
|
|
|
|
|
|
/* must be padded to 64 bit alignment */
|
2007-08-28 03:58:06 +00:00
|
|
|
} xfs_dsb_t;
|
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
|
* Sequence number values for the fields.
|
|
|
|
|
*/
|
|
|
|
|
typedef enum {
|
|
|
|
|
XFS_SBS_MAGICNUM, XFS_SBS_BLOCKSIZE, XFS_SBS_DBLOCKS, XFS_SBS_RBLOCKS,
|
|
|
|
|
XFS_SBS_REXTENTS, XFS_SBS_UUID, XFS_SBS_LOGSTART, XFS_SBS_ROOTINO,
|
|
|
|
|
XFS_SBS_RBMINO, XFS_SBS_RSUMINO, XFS_SBS_REXTSIZE, XFS_SBS_AGBLOCKS,
|
|
|
|
|
XFS_SBS_AGCOUNT, XFS_SBS_RBMBLOCKS, XFS_SBS_LOGBLOCKS,
|
|
|
|
|
XFS_SBS_VERSIONNUM, XFS_SBS_SECTSIZE, XFS_SBS_INODESIZE,
|
|
|
|
|
XFS_SBS_INOPBLOCK, XFS_SBS_FNAME, XFS_SBS_BLOCKLOG,
|
|
|
|
|
XFS_SBS_SECTLOG, XFS_SBS_INODELOG, XFS_SBS_INOPBLOG, XFS_SBS_AGBLKLOG,
|
|
|
|
|
XFS_SBS_REXTSLOG, XFS_SBS_INPROGRESS, XFS_SBS_IMAX_PCT, XFS_SBS_ICOUNT,
|
|
|
|
|
XFS_SBS_IFREE, XFS_SBS_FDBLOCKS, XFS_SBS_FREXTENTS, XFS_SBS_UQUOTINO,
|
|
|
|
|
XFS_SBS_GQUOTINO, XFS_SBS_QFLAGS, XFS_SBS_FLAGS, XFS_SBS_SHARED_VN,
|
|
|
|
|
XFS_SBS_INOALIGNMT, XFS_SBS_UNIT, XFS_SBS_WIDTH, XFS_SBS_DIRBLKLOG,
|
|
|
|
|
XFS_SBS_LOGSECTLOG, XFS_SBS_LOGSECTSIZE, XFS_SBS_LOGSUNIT,
|
2008-03-06 02:45:50 +00:00
|
|
|
XFS_SBS_FEATURES2, XFS_SBS_BAD_FEATURES2,
|
2005-04-16 22:20:36 +00:00
|
|
|
XFS_SBS_FIELDCOUNT
|
|
|
|
|
} xfs_sb_field_t;
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Mask values, defined based on the xfs_sb_field_t values.
|
|
|
|
|
* Only define the ones we're using.
|
|
|
|
|
*/
|
|
|
|
|
#define XFS_SB_MVAL(x) (1LL << XFS_SBS_ ## x)
|
|
|
|
|
#define XFS_SB_UUID XFS_SB_MVAL(UUID)
|
|
|
|
|
#define XFS_SB_FNAME XFS_SB_MVAL(FNAME)
|
|
|
|
|
#define XFS_SB_ROOTINO XFS_SB_MVAL(ROOTINO)
|
|
|
|
|
#define XFS_SB_RBMINO XFS_SB_MVAL(RBMINO)
|
|
|
|
|
#define XFS_SB_RSUMINO XFS_SB_MVAL(RSUMINO)
|
|
|
|
|
#define XFS_SB_VERSIONNUM XFS_SB_MVAL(VERSIONNUM)
|
|
|
|
|
#define XFS_SB_UQUOTINO XFS_SB_MVAL(UQUOTINO)
|
|
|
|
|
#define XFS_SB_GQUOTINO XFS_SB_MVAL(GQUOTINO)
|
|
|
|
|
#define XFS_SB_QFLAGS XFS_SB_MVAL(QFLAGS)
|
|
|
|
|
#define XFS_SB_SHARED_VN XFS_SB_MVAL(SHARED_VN)
|
|
|
|
|
#define XFS_SB_UNIT XFS_SB_MVAL(UNIT)
|
|
|
|
|
#define XFS_SB_WIDTH XFS_SB_MVAL(WIDTH)
|
[XFS] Lazy Superblock Counters
When we have a couple of hundred transactions on the fly at once, they all
typically modify the on disk superblock in some way.
create/unclink/mkdir/rmdir modify inode counts, allocation/freeing modify
free block counts.
When these counts are modified in a transaction, they must eventually lock
the superblock buffer and apply the mods. The buffer then remains locked
until the transaction is committed into the incore log buffer. The result
of this is that with enough transactions on the fly the incore superblock
buffer becomes a bottleneck.
The result of contention on the incore superblock buffer is that
transaction rates fall - the more pressure that is put on the superblock
buffer, the slower things go.
The key to removing the contention is to not require the superblock fields
in question to be locked. We do that by not marking the superblock dirty
in the transaction. IOWs, we modify the incore superblock but do not
modify the cached superblock buffer. In short, we do not log superblock
modifications to critical fields in the superblock on every transaction.
In fact we only do it just before we write the superblock to disk every
sync period or just before unmount.
This creates an interesting problem - if we don't log or write out the
fields in every transaction, then how do the values get recovered after a
crash? the answer is simple - we keep enough duplicate, logged information
in other structures that we can reconstruct the correct count after log
recovery has been performed.
It is the AGF and AGI structures that contain the duplicate information;
after recovery, we walk every AGI and AGF and sum their individual
counters to get the correct value, and we do a transaction into the log to
correct them. An optimisation of this is that if we have a clean unmount
record, we know the value in the superblock is correct, so we can avoid
the summation walk under normal conditions and so mount/recovery times do
not change under normal operation.
One wrinkle that was discovered during development was that the blocks
used in the freespace btrees are never accounted for in the AGF counters.
This was once a valid optimisation to make; when the filesystem is full,
the free space btrees are empty and consume no space. Hence when it
matters, the "accounting" is correct. But that means the when we do the
AGF summations, we would not have a correct count and xfs_check would
complain. Hence a new counter was added to track the number of blocks used
by the free space btrees. This is an *on-disk format change*.
As a result of this, lazy superblock counters are a mkfs option and at the
moment on linux there is no way to convert an old filesystem. This is
possible - xfs_db can be used to twiddle the right bits and then
xfs_repair will do the format conversion for you. Similarly, you can
convert backwards as well. At some point we'll add functionality to
xfs_admin to do the bit twiddling easily....
SGI-PV: 964999
SGI-Modid: xfs-linux-melb:xfs-kern:28652a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-24 05:26:31 +00:00
|
|
|
#define XFS_SB_ICOUNT XFS_SB_MVAL(ICOUNT)
|
|
|
|
|
#define XFS_SB_IFREE XFS_SB_MVAL(IFREE)
|
|
|
|
|
#define XFS_SB_FDBLOCKS XFS_SB_MVAL(FDBLOCKS)
|
2005-11-01 23:34:53 +00:00
|
|
|
#define XFS_SB_FEATURES2 XFS_SB_MVAL(FEATURES2)
|
2008-03-06 02:45:50 +00:00
|
|
|
#define XFS_SB_BAD_FEATURES2 XFS_SB_MVAL(BAD_FEATURES2)
|
2005-04-16 22:20:36 +00:00
|
|
|
#define XFS_SB_NUM_BITS ((int)XFS_SBS_FIELDCOUNT)
|
|
|
|
|
#define XFS_SB_ALL_BITS ((1LL << XFS_SB_NUM_BITS) - 1)
|
|
|
|
|
#define XFS_SB_MOD_BITS \
|
|
|
|
|
(XFS_SB_UUID | XFS_SB_ROOTINO | XFS_SB_RBMINO | XFS_SB_RSUMINO | \
|
|
|
|
|
XFS_SB_VERSIONNUM | XFS_SB_UQUOTINO | XFS_SB_GQUOTINO | \
|
2005-11-01 23:34:53 +00:00
|
|
|
XFS_SB_QFLAGS | XFS_SB_SHARED_VN | XFS_SB_UNIT | XFS_SB_WIDTH | \
|
2008-03-06 02:45:50 +00:00
|
|
|
XFS_SB_ICOUNT | XFS_SB_IFREE | XFS_SB_FDBLOCKS | XFS_SB_FEATURES2 | \
|
|
|
|
|
XFS_SB_BAD_FEATURES2)
|
2005-11-01 23:34:53 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Misc. Flags - warning - these will be cleared by xfs_repair unless
|
|
|
|
|
* a feature bit is set when the flag is used.
|
|
|
|
|
*/
|
|
|
|
|
#define XFS_SBF_NOFLAGS 0x00 /* no flags set */
|
|
|
|
|
#define XFS_SBF_READONLY 0x01 /* only read-only mounts allowed */
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* define max. shared version we can interoperate with
|
|
|
|
|
*/
|
|
|
|
|
#define XFS_SB_MAX_SHARED_VN 0
|
|
|
|
|
|
|
|
|
|
#define XFS_SB_VERSION_NUM(sbp) ((sbp)->sb_versionnum & XFS_SB_VERSION_NUMBITS)
|
|
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_good_version(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
/* We always support version 1-3 */
|
|
|
|
|
if (sbp->sb_versionnum >= XFS_SB_VERSION_1 &&
|
|
|
|
|
sbp->sb_versionnum <= XFS_SB_VERSION_3)
|
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
|
|
/* We support version 4 if all feature bits are supported */
|
|
|
|
|
if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4) {
|
|
|
|
|
if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKREALBITS) ||
|
|
|
|
|
((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) &&
|
|
|
|
|
(sbp->sb_features2 & ~XFS_SB_VERSION2_OKREALBITS)))
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
|
if (sbp->sb_shared_vn > XFS_SB_MAX_SHARED_VN)
|
|
|
|
|
return 0;
|
2005-11-02 03:38:42 +00:00
|
|
|
#else
|
2008-12-03 11:20:31 +00:00
|
|
|
if ((sbp->sb_versionnum & XFS_SB_VERSION_SHAREDBIT) &&
|
|
|
|
|
sbp->sb_shared_vn > XFS_SB_MAX_SHARED_VN)
|
|
|
|
|
return 0;
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
return 1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 0;
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-03-06 02:45:50 +00:00
|
|
|
/*
|
2008-04-10 02:19:34 +00:00
|
|
|
* Detect a mismatched features2 field. Older kernels read/wrote
|
|
|
|
|
* this into the wrong slot, so to be safe we keep them in sync.
|
2008-03-06 02:45:50 +00:00
|
|
|
*/
|
2008-04-10 02:19:34 +00:00
|
|
|
static inline int xfs_sb_has_mismatched_features2(xfs_sb_t *sbp)
|
2008-03-06 02:45:50 +00:00
|
|
|
{
|
2008-04-10 02:19:34 +00:00
|
|
|
return (sbp->sb_bad_features2 != sbp->sb_features2);
|
2008-03-06 02:45:50 +00:00
|
|
|
}
|
|
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline unsigned xfs_sb_version_tonew(unsigned v)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
if (v == XFS_SB_VERSION_1)
|
|
|
|
|
return XFS_SB_VERSION_4;
|
|
|
|
|
|
|
|
|
|
if (v == XFS_SB_VERSION_2)
|
|
|
|
|
return XFS_SB_VERSION_4 | XFS_SB_VERSION_ATTRBIT;
|
|
|
|
|
|
|
|
|
|
return XFS_SB_VERSION_4 | XFS_SB_VERSION_ATTRBIT |
|
|
|
|
|
XFS_SB_VERSION_NLINKBIT;
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline unsigned xfs_sb_version_toold(unsigned v)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
if (v & (XFS_SB_VERSION_QUOTABIT | XFS_SB_VERSION_ALIGNBIT))
|
|
|
|
|
return 0;
|
|
|
|
|
if (v & XFS_SB_VERSION_NLINKBIT)
|
|
|
|
|
return XFS_SB_VERSION_3;
|
|
|
|
|
if (v & XFS_SB_VERSION_ATTRBIT)
|
|
|
|
|
return XFS_SB_VERSION_2;
|
|
|
|
|
return XFS_SB_VERSION_1;
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasattr(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return sbp->sb_versionnum == XFS_SB_VERSION_2 ||
|
|
|
|
|
sbp->sb_versionnum == XFS_SB_VERSION_3 ||
|
|
|
|
|
(XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_ATTRBIT));
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline void xfs_sb_version_addattr(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
if (sbp->sb_versionnum == XFS_SB_VERSION_1)
|
|
|
|
|
sbp->sb_versionnum = XFS_SB_VERSION_2;
|
|
|
|
|
else if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4)
|
|
|
|
|
sbp->sb_versionnum |= XFS_SB_VERSION_ATTRBIT;
|
|
|
|
|
else
|
|
|
|
|
sbp->sb_versionnum = XFS_SB_VERSION_4 | XFS_SB_VERSION_ATTRBIT;
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasnlink(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return sbp->sb_versionnum == XFS_SB_VERSION_3 ||
|
|
|
|
|
(XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_NLINKBIT));
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline void xfs_sb_version_addnlink(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
if (sbp->sb_versionnum <= XFS_SB_VERSION_2)
|
|
|
|
|
sbp->sb_versionnum = XFS_SB_VERSION_3;
|
|
|
|
|
else
|
|
|
|
|
sbp->sb_versionnum |= XFS_SB_VERSION_NLINKBIT;
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasquota(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_QUOTABIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline void xfs_sb_version_addquota(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4)
|
|
|
|
|
sbp->sb_versionnum |= XFS_SB_VERSION_QUOTABIT;
|
|
|
|
|
else
|
|
|
|
|
sbp->sb_versionnum = xfs_sb_version_tonew(sbp->sb_versionnum) |
|
|
|
|
|
XFS_SB_VERSION_QUOTABIT;
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static inline int xfs_sb_version_hasalign(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_ALIGNBIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasdalign(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_DALIGNBIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasshared(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_SHAREDBIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasdirv2(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_DIRV2BIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_haslogv2(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_LOGV2BIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasextflgbit(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hassector(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_SECTORBIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2008-05-21 06:58:55 +00:00
|
|
|
static inline int xfs_sb_version_hasasciici(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
2008-05-21 06:58:55 +00:00
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_BORGBIT);
|
|
|
|
|
}
|
|
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasmorebits(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
|
|
|
|
|
(sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* sb_features2 bit version macros.
|
|
|
|
|
*
|
2005-11-01 23:34:53 +00:00
|
|
|
* For example, for a bit defined as XFS_SB_VERSION2_FUNBIT, has a macro:
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
2005-11-01 23:34:53 +00:00
|
|
|
* SB_VERSION_HASFUNBIT(xfs_sb_t *sbp)
|
2008-03-06 02:44:28 +00:00
|
|
|
* ((xfs_sb_version_hasmorebits(sbp) &&
|
2005-11-01 23:34:53 +00:00
|
|
|
* ((sbp)->sb_features2 & XFS_SB_VERSION2_FUNBIT)
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2005-11-02 03:38:42 +00:00
|
|
|
|
[XFS] Lazy Superblock Counters
When we have a couple of hundred transactions on the fly at once, they all
typically modify the on disk superblock in some way.
create/unclink/mkdir/rmdir modify inode counts, allocation/freeing modify
free block counts.
When these counts are modified in a transaction, they must eventually lock
the superblock buffer and apply the mods. The buffer then remains locked
until the transaction is committed into the incore log buffer. The result
of this is that with enough transactions on the fly the incore superblock
buffer becomes a bottleneck.
The result of contention on the incore superblock buffer is that
transaction rates fall - the more pressure that is put on the superblock
buffer, the slower things go.
The key to removing the contention is to not require the superblock fields
in question to be locked. We do that by not marking the superblock dirty
in the transaction. IOWs, we modify the incore superblock but do not
modify the cached superblock buffer. In short, we do not log superblock
modifications to critical fields in the superblock on every transaction.
In fact we only do it just before we write the superblock to disk every
sync period or just before unmount.
This creates an interesting problem - if we don't log or write out the
fields in every transaction, then how do the values get recovered after a
crash? the answer is simple - we keep enough duplicate, logged information
in other structures that we can reconstruct the correct count after log
recovery has been performed.
It is the AGF and AGI structures that contain the duplicate information;
after recovery, we walk every AGI and AGF and sum their individual
counters to get the correct value, and we do a transaction into the log to
correct them. An optimisation of this is that if we have a clean unmount
record, we know the value in the superblock is correct, so we can avoid
the summation walk under normal conditions and so mount/recovery times do
not change under normal operation.
One wrinkle that was discovered during development was that the blocks
used in the freespace btrees are never accounted for in the AGF counters.
This was once a valid optimisation to make; when the filesystem is full,
the free space btrees are empty and consume no space. Hence when it
matters, the "accounting" is correct. But that means the when we do the
AGF summations, we would not have a correct count and xfs_check would
complain. Hence a new counter was added to track the number of blocks used
by the free space btrees. This is an *on-disk format change*.
As a result of this, lazy superblock counters are a mkfs option and at the
moment on linux there is no way to convert an old filesystem. This is
possible - xfs_db can be used to twiddle the right bits and then
xfs_repair will do the format conversion for you. Similarly, you can
convert backwards as well. At some point we'll add functionality to
xfs_admin to do the bit twiddling easily....
SGI-PV: 964999
SGI-Modid: xfs-linux-melb:xfs-kern:28652a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-24 05:26:31 +00:00
|
|
|
static inline int xfs_sb_version_haslazysbcount(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return xfs_sb_version_hasmorebits(sbp) &&
|
|
|
|
|
(sbp->sb_features2 & XFS_SB_VERSION2_LAZYSBCOUNTBIT);
|
[XFS] Lazy Superblock Counters
When we have a couple of hundred transactions on the fly at once, they all
typically modify the on disk superblock in some way.
create/unclink/mkdir/rmdir modify inode counts, allocation/freeing modify
free block counts.
When these counts are modified in a transaction, they must eventually lock
the superblock buffer and apply the mods. The buffer then remains locked
until the transaction is committed into the incore log buffer. The result
of this is that with enough transactions on the fly the incore superblock
buffer becomes a bottleneck.
The result of contention on the incore superblock buffer is that
transaction rates fall - the more pressure that is put on the superblock
buffer, the slower things go.
The key to removing the contention is to not require the superblock fields
in question to be locked. We do that by not marking the superblock dirty
in the transaction. IOWs, we modify the incore superblock but do not
modify the cached superblock buffer. In short, we do not log superblock
modifications to critical fields in the superblock on every transaction.
In fact we only do it just before we write the superblock to disk every
sync period or just before unmount.
This creates an interesting problem - if we don't log or write out the
fields in every transaction, then how do the values get recovered after a
crash? the answer is simple - we keep enough duplicate, logged information
in other structures that we can reconstruct the correct count after log
recovery has been performed.
It is the AGF and AGI structures that contain the duplicate information;
after recovery, we walk every AGI and AGF and sum their individual
counters to get the correct value, and we do a transaction into the log to
correct them. An optimisation of this is that if we have a clean unmount
record, we know the value in the superblock is correct, so we can avoid
the summation walk under normal conditions and so mount/recovery times do
not change under normal operation.
One wrinkle that was discovered during development was that the blocks
used in the freespace btrees are never accounted for in the AGF counters.
This was once a valid optimisation to make; when the filesystem is full,
the free space btrees are empty and consume no space. Hence when it
matters, the "accounting" is correct. But that means the when we do the
AGF summations, we would not have a correct count and xfs_check would
complain. Hence a new counter was added to track the number of blocks used
by the free space btrees. This is an *on-disk format change*.
As a result of this, lazy superblock counters are a mkfs option and at the
moment on linux there is no way to convert an old filesystem. This is
possible - xfs_db can be used to twiddle the right bits and then
xfs_repair will do the format conversion for you. Similarly, you can
convert backwards as well. At some point we'll add functionality to
xfs_admin to do the bit twiddling easily....
SGI-PV: 964999
SGI-Modid: xfs-linux-melb:xfs-kern:28652a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-05-24 05:26:31 +00:00
|
|
|
}
|
|
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline int xfs_sb_version_hasattr2(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
return xfs_sb_version_hasmorebits(sbp) &&
|
|
|
|
|
(sbp->sb_features2 & XFS_SB_VERSION2_ATTR2BIT);
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
static inline void xfs_sb_version_addattr2(xfs_sb_t *sbp)
|
|
|
|
|
{
|
2008-12-03 11:20:31 +00:00
|
|
|
sbp->sb_versionnum |= XFS_SB_VERSION_MOREBITSBIT;
|
|
|
|
|
sbp->sb_features2 |= XFS_SB_VERSION2_ATTR2BIT;
|
2005-11-02 03:38:42 +00:00
|
|
|
}
|
|
|
|
|
|
2008-04-30 08:15:28 +00:00
|
|
|
static inline void xfs_sb_version_removeattr2(xfs_sb_t *sbp)
|
|
|
|
|
{
|
|
|
|
|
sbp->sb_features2 &= ~XFS_SB_VERSION2_ATTR2BIT;
|
|
|
|
|
if (!sbp->sb_features2)
|
|
|
|
|
sbp->sb_versionnum &= ~XFS_SB_VERSION_MOREBITSBIT;
|
|
|
|
|
}
|
|
|
|
|
|
2010-09-26 06:10:18 +00:00
|
|
|
static inline int xfs_sb_version_hasprojid32bit(xfs_sb_t *sbp)
|
|
|
|
|
{
|
|
|
|
|
return xfs_sb_version_hasmorebits(sbp) &&
|
|
|
|
|
(sbp->sb_features2 & XFS_SB_VERSION2_PROJID32BIT);
|
|
|
|
|
}
|
|
|
|
|
|
2012-11-15 22:20:37 +00:00
|
|
|
static inline int xfs_sb_version_hascrc(xfs_sb_t *sbp)
|
|
|
|
|
{
|
|
|
|
|
return (xfs_sb_version_hasmorebits(sbp) &&
|
|
|
|
|
(sbp->sb_features2 & XFS_SB_VERSION2_CRCBIT));
|
|
|
|
|
}
|
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
|
* end of superblock version macros
|
|
|
|
|
*/
|
|
|
|
|
|
2005-11-02 03:38:42 +00:00
|
|
|
#define XFS_SB_DADDR ((xfs_daddr_t)0) /* daddr in filesystem/ag */
|
2005-04-16 22:20:36 +00:00
|
|
|
#define XFS_SB_BLOCK(mp) XFS_HDR_BLOCK(mp, XFS_SB_DADDR)
|
2011-07-22 23:40:15 +00:00
|
|
|
#define XFS_BUF_TO_SBP(bp) ((xfs_dsb_t *)((bp)->b_addr))
|
2005-11-02 03:38:42 +00:00
|
|
|
|
|
|
|
|
#define XFS_HDR_BLOCK(mp,d) ((xfs_agblock_t)XFS_BB_TO_FSBT(mp,d))
|
|
|
|
|
#define XFS_DADDR_TO_FSB(mp,d) XFS_AGB_TO_FSB(mp, \
|
2009-01-15 05:22:07 +00:00
|
|
|
xfs_daddr_to_agno(mp,d), xfs_daddr_to_agbno(mp,d))
|
2005-11-02 03:38:42 +00:00
|
|
|
#define XFS_FSB_TO_DADDR(mp,fsbno) XFS_AGB_TO_DADDR(mp, \
|
|
|
|
|
XFS_FSB_TO_AGNO(mp,fsbno), XFS_FSB_TO_AGBNO(mp,fsbno))
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* File system sector to basic block conversions.
|
|
|
|
|
*/
|
|
|
|
|
#define XFS_FSS_TO_BB(mp,sec) ((sec) << (mp)->m_sectbb_log)
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* File system block to basic block conversions.
|
|
|
|
|
*/
|
|
|
|
|
#define XFS_FSB_TO_BB(mp,fsbno) ((fsbno) << (mp)->m_blkbb_log)
|
|
|
|
|
#define XFS_BB_TO_FSB(mp,bb) \
|
|
|
|
|
(((bb) + (XFS_FSB_TO_BB(mp,1) - 1)) >> (mp)->m_blkbb_log)
|
|
|
|
|
#define XFS_BB_TO_FSBT(mp,bb) ((bb) >> (mp)->m_blkbb_log)
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* File system block to byte conversions.
|
|
|
|
|
*/
|
|
|
|
|
#define XFS_FSB_TO_B(mp,fsbno) ((xfs_fsize_t)(fsbno) << (mp)->m_sb.sb_blocklog)
|
|
|
|
|
#define XFS_B_TO_FSB(mp,b) \
|
|
|
|
|
((((__uint64_t)(b)) + (mp)->m_blockmask) >> (mp)->m_sb.sb_blocklog)
|
|
|
|
|
#define XFS_B_TO_FSBT(mp,b) (((__uint64_t)(b)) >> (mp)->m_sb.sb_blocklog)
|
|
|
|
|
#define XFS_B_FSB_OFFSET(mp,b) ((b) & (mp)->m_blockmask)
|
|
|
|
|
|
|
|
|
|
#endif /* __XFS_SB_H__ */
|