[PATCH 07/16] xfs: store xfs_mount in the buftarg instead of in the xfs_buf

Dave Chinner
2010-09-22T06:44:11Z

From: Dave Chinner <dchinner@redhat.com>

Each buffer contains both a buftarg pointer and a mount pointer. If
we add a mount pointer into the buftarg, we can avoid needing the
b_mount field in every buffer and grab it from the buftarg when
needed instead. This shrinks the xfs_buf by 8 bytes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
---
fs/xfs/linux-2.6/xfs_buf.c | 9 ++++-----
fs/xfs/linux-2.6/xfs_buf.h | 5 +++--
fs/xfs/linux-2.6/xfs_super.c | 8 +++++---
fs/xfs/xfs_buf_item.c | 3 +--
fs/xfs/xfs_log_recover.c | 16 +++++++---------
5 files changed, 20 insertions(+), 21 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index c8420c0..49374ae 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -894,7 +894,7 @@ xfs_buf_lock(
trace_xfs_buf_lock(bp, _RET_IP_);

if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
- xfs_log_force(bp->b_mount, 0);
+ xfs_log_force(bp->b_target->bt_mount, 0);
if (atomic_read(&bp->b_io_remaining))
blk_run_address_space(bp->b_target->bt_mapping);
down(&bp->b_sema);
@@ -1017,7 +1017,6 @@ xfs_bwrite(
{
int error;

- bp->b_mount = mp;
bp->b_flags |= XBF_WRITE;
bp->b_flags &= ~(XBF_ASYNC | XBF_READ);

@@ -1038,8 +1037,6 @@ xfs_bdwrite(
{
trace_xfs_buf_bdwrite(bp, _RET_IP_);

- bp->b_mount = mp;
-
bp->b_flags &= ~XBF_READ;
bp->b_flags |= (XBF_DELWRI | XBF_ASYNC);

@@ -1128,7 +1125,7 @@ int
xfs_bdstrat_cb(
struct xfs_buf *bp)
{
- if (XFS_FORCED_SHUTDOWN(bp->b_mount)) {
+ if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
trace_xfs_bdstrat_shut(bp, _RET_IP_);
/*
* Metadata write that didn't get logged but
@@ -1644,6 +1641,7 @@ out_error:

xfs_buftarg_t *
xfs_alloc_buftarg(
+ struct xfs_mount *mp,
struct block_device *bdev,
int external,
const char *fsname)
@@ -1652,6 +1650,7 @@ xfs_alloc_buftarg(

btp = kmem_zalloc(sizeof(*btp), KM_SLEEP);

+ btp->bt_mount = mp;
btp->bt_dev = bdev->bd_dev;
btp->bt_bdev = bdev;
if (xfs_setsize_buftarg_early(btp, bdev))
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index 23da2aa..e3aa8c0 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -132,6 +132,7 @@ typedef struct xfs_buftarg {
dev_t bt_dev;
struct block_device *bt_bdev;
struct address_space *bt_mapping;
+ struct xfs_mount *bt_mount;
unsigned int bt_bsize;
unsigned int bt_sshift;
size_t bt_smask;
@@ -189,7 +190,6 @@ typedef struct xfs_buf {
struct completion b_iowait; /* queue for I/O waiters */
void *b_fspriv;
void *b_fspriv2;
- struct xfs_mount *b_mount;
unsigned short b_error; /* error code on I/O */
unsigned int b_page_count; /* size of page array */
unsigned int b_offset; /* page offset in first page */
@@ -377,7 +377,8 @@ static inline void xfs_buf_relse(xfs_buf_t *bp)
/*
* Handling of buftargs.
*/
-extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int, const char *);
+extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
+ struct block_device *, int, const char *);
extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
extern void xfs_wait_buftarg(xfs_buftarg_t *);
extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index a4e0797..62501ee 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -758,18 +758,20 @@ xfs_open_devices(
* Setup xfs_mount buffer target pointers
*/
error = ENOMEM;
- mp->m_ddev_targp = xfs_alloc_buftarg(ddev, 0, mp->m_fsname);
+ mp->m_ddev_targp = xfs_alloc_buftarg(mp, ddev, 0, mp->m_fsname);
if (!mp->m_ddev_targp)
goto out_close_rtdev;

if (rtdev) {
- mp->m_rtdev_targp = xfs_alloc_buftarg(rtdev, 1, mp->m_fsname);
+ mp->m_rtdev_targp = xfs_alloc_buftarg(mp, rtdev, 1,
+ mp->m_fsname);
if (!mp->m_rtdev_targp)
goto out_free_ddev_targ;
}

if (logdev && logdev != ddev) {
- mp->m_logdev_targp = xfs_alloc_buftarg(logdev, 1, mp->m_fsname);
+ mp->m_logdev_targp = xfs_alloc_buftarg(mp, logdev, 1,
+ mp->m_fsname);
if (!mp->m_logdev_targp)
goto out_free_rtdev_targ;
} else {
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 1b09d7a..ee75576 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -692,8 +692,7 @@ xfs_buf_item_init(
* the first. If we do already have one, there is
* nothing to do here so return.
*/
- if (bp->b_mount != mp)
- bp->b_mount = mp;
+ ASSERT(bp->b_target->bt_mount == mp);
if (XFS_BUF_FSPRIVATE(bp, void *) != NULL) {
lip = XFS_BUF_FSPRIVATE(bp, xfs_log_item_t *);
if (lip->li_type == XFS_LI_BUF) {
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 2f57be0..0e08e30 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -322,10 +322,11 @@ xlog_recover_iodone(
* this during recovery. One strike!
*/
xfs_ioerror_alert("xlog_recover_iodone",
- bp->b_mount, bp, XFS_BUF_ADDR(bp));
- xfs_force_shutdown(bp->b_mount, SHUTDOWN_META_IO_ERROR);
+ bp->b_target->bt_mount, bp,
+ XFS_BUF_ADDR(bp));
+ xfs_force_shutdown(bp->b_target->bt_mount,
+ SHUTDOWN_META_IO_ERROR);
}
- bp->b_mount = NULL;
XFS_BUF_CLR_IODONE_FUNC(bp);
xfs_biodone(bp);
}
@@ -2276,8 +2277,7 @@ xlog_recover_do_buffer_trans(
XFS_BUF_STALE(bp);
error = xfs_bwrite(mp, bp);
} else {
- ASSERT(bp->b_mount == NULL || bp->b_mount == mp);
- bp->b_mount = mp;
+ ASSERT(bp->b_target->bt_mount == mp);
XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
xfs_bdwrite(mp, bp);
}
@@ -2541,8 +2541,7 @@ xlog_recover_do_inode_trans(
}

write_inode_buffer:
- ASSERT(bp->b_mount == NULL || bp->b_mount == mp);
- bp->b_mount = mp;
+ ASSERT(bp->b_target->bt_mount == mp);
XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
xfs_bdwrite(mp, bp);
error:
@@ -2679,8 +2678,7 @@ xlog_recover_do_dquot_trans(
memcpy(ddq, recddq, item->ri_buf[1].i_len);

ASSERT(dq_f->qlf_size == 2);
- ASSERT(bp->b_mount == NULL || bp->b_mount == mp);
- bp->b_mount = mp;
+ ASSERT(bp->b_target->bt_mount == mp);
XFS_BUF_SET_IODONE_FUNC(bp, xlog_recover_iodone);
xfs_bdwrite(mp, bp);

--
1.7.1