alistair23-linux/fs/xfs/xfs_trans_inode.c
Christoph Hellwig aa72a5cf00 xfs: simplify xfs_trans_iget
xfs_trans_iget is a wrapper for xfs_iget that adds the inode to the
transaction after it is read.  Except when the inode already is in the
inode cache, in which case it returns the existing locked inode with
increment lock recursion counts.

Now, no one in the tree every decrements these lock recursion counts,
so any user of this gets a potential double unlock when both the original
owner of the inode and the xfs_trans_iget caller unlock it.  When looking
back in a git bisect in the historic XFS tree there was only one place
that decremented these counts, xfs_trans_iput.  Introduced in commit
ca25df7a840f426eb566d52667b6950b92bb84b5 by Adam Sweeney in 1993,
and removed in commit 19f899a3ab155ff6a49c0c79b06f2f61059afaf3 by
Steve Lord in 2003.  And as long as it didn't slip through git bisects
cracks never actually used in that time frame.

A quick audit of the callers of xfs_trans_iget shows that no caller
really relies on this behaviour fortunately - xfs_ialloc allows this
inode from disk so it must not be there before, and all the RT allocator
routines only every add each RT bitmap inode once.

In addition to removing lots of code and reducing the size of the inode
item this patch also avoids the double inode cache lookup in each
create/mkdir/mknod transaction.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
2009-09-01 12:46:16 -05:00

205 lines
5 KiB
C

/*
* Copyright (c) 2000,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* 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.
*
* 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
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_trans_priv.h"
#include "xfs_inode_item.h"
#ifdef XFS_TRANS_DEBUG
STATIC void
xfs_trans_inode_broot_debug(
xfs_inode_t *ip);
#else
#define xfs_trans_inode_broot_debug(ip)
#endif
/*
* Get an inode and join it to the transaction.
*/
int
xfs_trans_iget(
xfs_mount_t *mp,
xfs_trans_t *tp,
xfs_ino_t ino,
uint flags,
uint lock_flags,
xfs_inode_t **ipp)
{
int error;
error = xfs_iget(mp, tp, ino, flags, lock_flags, ipp, 0);
if (!error && tp)
xfs_trans_ijoin(tp, *ipp, lock_flags);
return error;
}
/*
* Add the locked inode to the transaction.
* The inode must be locked, and it cannot be associated with any
* transaction. The caller must specify the locks already held
* on the inode.
*/
void
xfs_trans_ijoin(
xfs_trans_t *tp,
xfs_inode_t *ip,
uint lock_flags)
{
xfs_inode_log_item_t *iip;
ASSERT(ip->i_transp == NULL);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
ASSERT(lock_flags & XFS_ILOCK_EXCL);
if (ip->i_itemp == NULL)
xfs_inode_item_init(ip, ip->i_mount);
iip = ip->i_itemp;
ASSERT(iip->ili_flags == 0);
/*
* Get a log_item_desc to point at the new item.
*/
(void) xfs_trans_add_item(tp, (xfs_log_item_t*)(iip));
xfs_trans_inode_broot_debug(ip);
/*
* If the IO lock is already held, mark that in the inode log item.
*/
if (lock_flags & XFS_IOLOCK_EXCL) {
iip->ili_flags |= XFS_ILI_IOLOCKED_EXCL;
} else if (lock_flags & XFS_IOLOCK_SHARED) {
iip->ili_flags |= XFS_ILI_IOLOCKED_SHARED;
}
/*
* Initialize i_transp so we can find it with xfs_inode_incore()
* in xfs_trans_iget() above.
*/
ip->i_transp = tp;
}
/*
* Mark the inode as not needing to be unlocked when the inode item's
* IOP_UNLOCK() routine is called. The inode must already be locked
* and associated with the given transaction.
*/
/*ARGSUSED*/
void
xfs_trans_ihold(
xfs_trans_t *tp,
xfs_inode_t *ip)
{
ASSERT(ip->i_transp == tp);
ASSERT(ip->i_itemp != NULL);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
ip->i_itemp->ili_flags |= XFS_ILI_HOLD;
}
/*
* This is called to mark the fields indicated in fieldmask as needing
* to be logged when the transaction is committed. The inode must
* already be associated with the given transaction.
*
* The values for fieldmask are defined in xfs_inode_item.h. We always
* log all of the core inode if any of it has changed, and we always log
* all of the inline data/extents/b-tree root if any of them has changed.
*/
void
xfs_trans_log_inode(
xfs_trans_t *tp,
xfs_inode_t *ip,
uint flags)
{
xfs_log_item_desc_t *lidp;
ASSERT(ip->i_transp == tp);
ASSERT(ip->i_itemp != NULL);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
lidp = xfs_trans_find_item(tp, (xfs_log_item_t*)(ip->i_itemp));
ASSERT(lidp != NULL);
tp->t_flags |= XFS_TRANS_DIRTY;
lidp->lid_flags |= XFS_LID_DIRTY;
/*
* Always OR in the bits from the ili_last_fields field.
* This is to coordinate with the xfs_iflush() and xfs_iflush_done()
* routines in the eventual clearing of the ilf_fields bits.
* See the big comment in xfs_iflush() for an explanation of
* this coordination mechanism.
*/
flags |= ip->i_itemp->ili_last_fields;
ip->i_itemp->ili_format.ilf_fields |= flags;
}
#ifdef XFS_TRANS_DEBUG
/*
* Keep track of the state of the inode btree root to make sure we
* log it properly.
*/
STATIC void
xfs_trans_inode_broot_debug(
xfs_inode_t *ip)
{
xfs_inode_log_item_t *iip;
ASSERT(ip->i_itemp != NULL);
iip = ip->i_itemp;
if (iip->ili_root_size != 0) {
ASSERT(iip->ili_orig_root != NULL);
kmem_free(iip->ili_orig_root);
iip->ili_root_size = 0;
iip->ili_orig_root = NULL;
}
if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
ASSERT((ip->i_df.if_broot != NULL) &&
(ip->i_df.if_broot_bytes > 0));
iip->ili_root_size = ip->i_df.if_broot_bytes;
iip->ili_orig_root =
(char*)kmem_alloc(iip->ili_root_size, KM_SLEEP);
memcpy(iip->ili_orig_root, (char*)(ip->i_df.if_broot),
iip->ili_root_size);
}
}
#endif