xfs: remove xfs_btree_cur private firstblock field

Source kernel commit: cf612de732cb6ef626019ca085406d183f0a055a

The bmbt cursor private structure has a firstblock field that is
used to maintain locking order on bmbt allocations. The field holds
an actual firstblock value (as opposed to a pointer), so it is
initialized on cursor creation, updated on allocation and then the
value is transferred back to the source before the cursor is
destroyed.

This value is always transferred from and back to the ->t_firstblock
field. Since xfs_btree_cur already carries a reference to the
transaction, we can remove this field from xfs_btree_cur and the
associated copying. The bmbt allocations will update the value in
the transaction directly.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index 1d0217788c67a13b9e7135d3823f2ddeb234e34d..2c0eb94ea0fbbec00b69f6ba8c30a7e9658cdac7 100644 (file)
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -679,7 +679,6 @@ xfs_bmap_extents_to_btree(
         * Need a cursor.  Can't allocate until bb_level is filled in.
         */
        cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
-       cur->bc_private.b.firstblock = tp->t_firstblock;
        cur->bc_private.b.flags = wasdel ? XFS_BTCUR_BPRV_WASDEL : 0;
        /*
         * Convert to a btree with two levels, one record in root.
@@ -723,7 +722,7 @@ xfs_bmap_extents_to_btree(
         */
        ASSERT(tp->t_firstblock == NULLFSBLOCK ||
               args.agno >= XFS_FSB_TO_AGNO(mp, tp->t_firstblock));
-       tp->t_firstblock = cur->bc_private.b.firstblock = args.fsbno;
+       tp->t_firstblock = args.fsbno;
        cur->bc_private.b.allocated++;
        ip->i_d.di_nblocks++;
        xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, 1L);
@@ -916,7 +915,6 @@ xfs_bmap_add_attrfork_btree(
                *flags |= XFS_ILOG_DBROOT;
        else {
                cur = xfs_bmbt_init_cursor(mp, tp, ip, XFS_DATA_FORK);
-               cur->bc_private.b.firstblock = tp->t_firstblock;
                error = xfs_bmbt_lookup_first(cur, &stat);
                if (error)
                        goto error0;
@@ -928,7 +926,6 @@ xfs_bmap_add_attrfork_btree(
                        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
                        return -ENOSPC;
                }
-               tp->t_firstblock = cur->bc_private.b.firstblock;
                cur->bc_private.b.allocated = 0;
                xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
        }
@@ -4049,14 +4046,10 @@ xfs_bmapi_allocate(
        if (error)
                return error;
 
-       if (bma->cur)
-               bma->cur->bc_private.b.firstblock = bma->tp->t_firstblock;
        if (bma->blkno == NULLFSBLOCK)
                return 0;
-       if ((ifp->if_flags & XFS_IFBROOT) && !bma->cur) {
+       if ((ifp->if_flags & XFS_IFBROOT) && !bma->cur)
                bma->cur = xfs_bmbt_init_cursor(mp, bma->tp, bma->ip, whichfork);
-               bma->cur->bc_private.b.firstblock = bma->tp->t_firstblock;
-       }
        /*
         * Bump the number of extents we've allocated
         * in this call.
@@ -4142,7 +4135,6 @@ xfs_bmapi_convert_unwritten(
        if ((ifp->if_flags & XFS_IFBROOT) && !bma->cur) {
                bma->cur = xfs_bmbt_init_cursor(bma->ip->i_mount, bma->tp,
                                        bma->ip, whichfork);
-               bma->cur->bc_private.b.firstblock = bma->tp->t_firstblock;
        }
        mval->br_state = (mval->br_state == XFS_EXT_UNWRITTEN)
                                ? XFS_EXT_NORM : XFS_EXT_UNWRITTEN;
@@ -4449,13 +4441,6 @@ error0:
                xfs_trans_log_inode(tp, ip, bma.logflags);
 
        if (bma.cur) {
-               if (!error) {
-                       ASSERT(tp->t_firstblock == NULLFSBLOCK ||
-                              XFS_FSB_TO_AGNO(mp, tp->t_firstblock) <=
-                              XFS_FSB_TO_AGNO(mp,
-                                      bma.cur->bc_private.b.firstblock));
-                       tp->t_firstblock = bma.cur->bc_private.b.firstblock;
-               }
                xfs_btree_del_cursor(bma.cur,
                        error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
        }
@@ -4519,7 +4504,6 @@ xfs_bmapi_remap(
 
        if (ifp->if_flags & XFS_IFBROOT) {
                cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
-               cur->bc_private.b.firstblock = tp->t_firstblock;
                cur->bc_private.b.flags = 0;
        }
 
@@ -5180,7 +5164,6 @@ __xfs_bunmapi(
        if (ifp->if_flags & XFS_IFBROOT) {
                ASSERT(XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE);
                cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
-               cur->bc_private.b.firstblock = tp->t_firstblock;
                cur->bc_private.b.flags = 0;
        } else
                cur = NULL;
@@ -5448,10 +5431,8 @@ error0:
        if (logflags)
                xfs_trans_log_inode(tp, ip, logflags);
        if (cur) {
-               if (!error) {
-                       tp->t_firstblock = cur->bc_private.b.firstblock;
+               if (!error)
                        cur->bc_private.b.allocated = 0;
-               }
                xfs_btree_del_cursor(cur,
                        error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
        }
@@ -5667,7 +5648,6 @@ xfs_bmap_collapse_extents(
 
        if (ifp->if_flags & XFS_IFBROOT) {
                cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
-               cur->bc_private.b.firstblock = tp->t_firstblock;
                cur->bc_private.b.flags = 0;
        }
 
@@ -5787,7 +5767,6 @@ xfs_bmap_insert_extents(
 
        if (ifp->if_flags & XFS_IFBROOT) {
                cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
-               cur->bc_private.b.firstblock = tp->t_firstblock;
                cur->bc_private.b.flags = 0;
        }
 
@@ -5909,7 +5888,6 @@ xfs_bmap_split_extent_at(
 
        if (ifp->if_flags & XFS_IFBROOT) {
                cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
-               cur->bc_private.b.firstblock = tp->t_firstblock;
                cur->bc_private.b.flags = 0;
                error = xfs_bmbt_lookup_eq(cur, &got, &i);
                if (error)

diff --git a/libxfs/xfs_bmap_btree.c b/libxfs/xfs_bmap_btree.c
index f94dc4c9795e4d185d3d7238366c2b9e4c8f51d6..5b9d547b4cf7f9732f81ee2a6e5fa80a6abf6ea8 100644 (file)
--- a/libxfs/xfs_bmap_btree.c
+++ b/libxfs/xfs_bmap_btree.c
@@ -172,7 +172,6 @@ xfs_bmbt_dup_cursor(
         * Copy the firstblock, dfops, and flags values,
         * since init cursor doesn't get them.
         */
-       new->bc_private.b.firstblock = cur->bc_private.b.firstblock;
        new->bc_private.b.flags = cur->bc_private.b.flags;
 
        return new;
@@ -183,11 +182,11 @@ xfs_bmbt_update_cursor(
        struct xfs_btree_cur    *src,
        struct xfs_btree_cur    *dst)
 {
-       ASSERT((dst->bc_private.b.firstblock != NULLFSBLOCK) ||
+       ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
               (dst->bc_private.b.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
 
        dst->bc_private.b.allocated += src->bc_private.b.allocated;
-       dst->bc_private.b.firstblock = src->bc_private.b.firstblock;
+       dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
 
        src->bc_private.b.allocated = 0;
 }
@@ -205,7 +204,7 @@ xfs_bmbt_alloc_block(
        memset(&args, 0, sizeof(args));
        args.tp = cur->bc_tp;
        args.mp = cur->bc_mp;
-       args.fsbno = cur->bc_private.b.firstblock;
+       args.fsbno = cur->bc_tp->t_firstblock;
        args.firstblock = args.fsbno;
        xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_private.b.ip->i_ino,
                        cur->bc_private.b.whichfork);
@@ -260,7 +259,7 @@ xfs_bmbt_alloc_block(
        }
 
        ASSERT(args.len == 1);
-       cur->bc_private.b.firstblock = args.fsbno;
+       cur->bc_tp->t_firstblock = args.fsbno;
        cur->bc_private.b.allocated++;
        cur->bc_private.b.ip->i_d.di_nblocks++;
        xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
@@ -559,7 +558,6 @@ xfs_bmbt_init_cursor(
 
        cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
        cur->bc_private.b.ip = ip;
-       cur->bc_private.b.firstblock = NULLFSBLOCK;
        cur->bc_private.b.allocated = 0;
        cur->bc_private.b.flags = 0;
        cur->bc_private.b.whichfork = whichfork;

diff --git a/libxfs/xfs_btree.h b/libxfs/xfs_btree.h
index e9c0c7550ac16615c99fce59b28e51774bfd2398..1b84de44d2cd0bba92e2cbe102fbb33bbf398935 100644 (file)
--- a/libxfs/xfs_btree.h
+++ b/libxfs/xfs_btree.h
@@ -214,7 +214,6 @@ typedef struct xfs_btree_cur
                } a;
                struct {                        /* needed for BMAP */
                        struct xfs_inode *ip;   /* pointer to our inode */
-                       xfs_fsblock_t   firstblock;     /* 1st blk allocated */
                        int             allocated;      /* count of alloced */
                        short           forksize;       /* fork's inode space */
                        char            whichfork;      /* data or attr fork */