Re: [PATCH 07/47] xfs: add function pointers for get/update keys to the btree

Darrick J. Wong
2016-08-03T00:13:34Z

On Tue, Aug 02, 2016 at 05:23:25AM -0700, Christoph Hellwig wrote:
> On Mon, Aug 01, 2016 at 10:33:31AM -0700, Darrick J. Wong wrote:
> > That's roughly the approach I took in previous versions of this patch,
> > but using the OVERLAPPING flag to dispatch the overlapped vs. non-
> > versions of the get*keys and updkey* functions confused Dave, so he
> > asked me to add to function pointers[1] to the btree ops and dispatch
> > that way.
>
> I remember I had a similar disagreement with Dave on the long vs
> short pointers when doing the initial common btree work, and
> I prevailed using the flag :)
>
> Below is a patch to on top of your for-dave-for-4.8-2 branch
> which uses the flag, but also keeps your useful refactoring.
>
> This both reduces source:
>
> 6 files changed, 61 insertions(+), 136 deletions(-)
>
> as well as binary:
>
> hch@brick:~/work/xfs$ size xfs.o-*
> text data bss dec hex filename
> 911881 160951 1568 1074400 1064e0 xfs.o-flag
> 912457 160951 1568 1074976 106720 xfs.o-pointer
>
> sizes and makes the whole thing much easier to follow and understand.

Ok, sounds good. Disentangling this was actually simpler than I thought it
would be, so I tossed it on the branch I'm (imminently) sending to Dave.
I reworked some of the comments to reflect the newer approach.

We ought to collect a S-o-B from you too.

--D

>
> diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
> index c60eeb8..5ba2dac 100644
> --- a/fs/xfs/libxfs/xfs_alloc_btree.c
> +++ b/fs/xfs/libxfs/xfs_alloc_btree.c
> @@ -403,10 +403,6 @@ static const struct xfs_btree_ops xfs_allocbt_ops = {
> .keys_inorder = xfs_allocbt_keys_inorder,
> .recs_inorder = xfs_allocbt_recs_inorder,
> #endif
> -
> - .get_leaf_keys = xfs_btree_get_leaf_keys,
> - .get_node_keys = xfs_btree_get_node_keys,
> - .update_keys = xfs_btree_update_keys,
> };
>
> /*
> diff --git a/fs/xfs/libxfs/xfs_bmap_btree.c b/fs/xfs/libxfs/xfs_bmap_btree.c
> index 9e34ca4..cd85274 100644
> --- a/fs/xfs/libxfs/xfs_bmap_btree.c
> +++ b/fs/xfs/libxfs/xfs_bmap_btree.c
> @@ -763,10 +763,6 @@ static const struct xfs_btree_ops xfs_bmbt_ops = {
> .keys_inorder = xfs_bmbt_keys_inorder,
> .recs_inorder = xfs_bmbt_recs_inorder,
> #endif
> -
> - .get_leaf_keys = xfs_btree_get_leaf_keys,
> - .get_node_keys = xfs_btree_get_node_keys,
> - .update_keys = xfs_btree_update_keys,
> };
>
> /*
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index fe5f27e..45a9545b 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -1951,29 +1951,6 @@ error0:
> return error;
> }
>
> -/* Determine the low key of a leaf block (simple) */
> -void
> -xfs_btree_get_leaf_keys(
> - struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block,
> - union xfs_btree_key *key)
> -{
> - union xfs_btree_rec *rec;
> -
> - rec = xfs_btree_rec_addr(cur, 1, block);
> - cur->bc_ops->init_key_from_rec(key, rec);
> -}
> -
> -/* Determine the low key of a node block (simple) */
> -void
> -xfs_btree_get_node_keys(
> - struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block,
> - union xfs_btree_key *key)
> -{
> - memcpy(key, xfs_btree_key_addr(cur, 1, block), cur->bc_ops->key_len);
> -}
> -
> /* Find the high key storage area from a regular key. */
> STATIC union xfs_btree_key *
> xfs_btree_high_key_from_key(
> @@ -1985,38 +1962,41 @@ xfs_btree_high_key_from_key(
> (cur->bc_ops->key_len / 2));
> }
>
> -/* Determine the low and high keys of a leaf block (overlapped) */
> -void
> -xfs_btree_get_leaf_keys_overlapped(
> +/* Determine the low (and high if overlapped) key of a leaf block */
> +STATIC void
> +xfs_btree_get_leaf_keys(
> struct xfs_btree_cur *cur,
> struct xfs_btree_block *block,
> union xfs_btree_key *key)
> {
> - int n;
> union xfs_btree_rec *rec;
> - union xfs_btree_key max_hkey;
> - union xfs_btree_key hkey;
> - union xfs_btree_key *high;
>
> - ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
> rec = xfs_btree_rec_addr(cur, 1, block);
> cur->bc_ops->init_key_from_rec(key, rec);
>
> - cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
> - for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
> - rec = xfs_btree_rec_addr(cur, n, block);
> - cur->bc_ops->init_high_key_from_rec(&hkey, rec);
> - if (cur->bc_ops->diff_two_keys(cur, &hkey, &max_hkey) > 0)
> - max_hkey = hkey;
> - }
> + if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
> + union xfs_btree_key max_hkey;
> + union xfs_btree_key hkey;
> + union xfs_btree_key *high;
> + int n;
> +
> + cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
> + for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
> + rec = xfs_btree_rec_addr(cur, n, block);
> + cur->bc_ops->init_high_key_from_rec(&hkey, rec);
> + if (cur->bc_ops->diff_two_keys(cur, &hkey, &max_hkey)
> + > 0)
> + max_hkey = hkey;
> + }
>
> - high = xfs_btree_high_key_from_key(cur, key);
> - memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
> + high = xfs_btree_high_key_from_key(cur, key);
> + memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
> + }
> }
>
> /* Determine the low and high keys of a node block (overlapped) */
> -void
> -xfs_btree_get_node_keys_overlapped(
> +STATIC void
> +xfs_btree_get_node_keys(
> struct xfs_btree_cur *cur,
> struct xfs_btree_block *block,
> union xfs_btree_key *key)
> @@ -2026,19 +2006,23 @@ xfs_btree_get_node_keys_overlapped(
> union xfs_btree_key *max_hkey;
> union xfs_btree_key *high;
>
> - ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
> - memcpy(key, xfs_btree_key_addr(cur, 1, block),
> - cur->bc_ops->key_len / 2);
> -
> - max_hkey = xfs_btree_high_key_addr(cur, 1, block);
> - for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
> - hkey = xfs_btree_high_key_addr(cur, n, block);
> - if (cur->bc_ops->diff_two_keys(cur, hkey, max_hkey) > 0)
> - max_hkey = hkey;
> - }
> + if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
> + memcpy(key, xfs_btree_key_addr(cur, 1, block),
> + cur->bc_ops->key_len / 2);
> +
> + max_hkey = xfs_btree_high_key_addr(cur, 1, block);
> + for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
> + hkey = xfs_btree_high_key_addr(cur, n, block);
> + if (cur->bc_ops->diff_two_keys(cur, hkey, max_hkey) > 0)
> + max_hkey = hkey;
> + }
>
> - high = xfs_btree_high_key_from_key(cur, key);
> - memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
> + high = xfs_btree_high_key_from_key(cur, key);
> + memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
> + } else {
> + memcpy(key, xfs_btree_key_addr(cur, 1, block),
> + cur->bc_ops->key_len);
> + }
> }
>
> /* Derive the keys for any btree block. */
> @@ -2049,9 +2033,9 @@ xfs_btree_get_keys(
> union xfs_btree_key *key)
> {
> if (be16_to_cpu(block->bb_level) == 0)
> - cur->bc_ops->get_leaf_keys(cur, block, key);
> + xfs_btree_get_leaf_keys(cur, block, key);
> else
> - cur->bc_ops->get_node_keys(cur, block, key);
> + xfs_btree_get_node_keys(cur, block, key);
> }
>
> /*
> @@ -2125,28 +2109,12 @@ __xfs_btree_updkeys(
> xfs_btree_log_keys(cur, bp, ptr, ptr);
> if (level + 1 >= cur->bc_nlevels)
> break;
> - cur->bc_ops->get_node_keys(cur, block, lkey);
> + xfs_btree_get_node_keys(cur, block, lkey);
> }
>
> return 0;
> }
>
> -/*
> - * Update all the keys from some level in cursor back to the root, stopping
> - * when we find a key pair that don't need updating.
> - */
> -int
> -xfs_btree_update_keys_overlapped(
> - struct xfs_btree_cur *cur,
> - int level)
> -{
> - struct xfs_buf *bp;
> - struct xfs_btree_block *block;
> -
> - block = xfs_btree_get_block(cur, level, &bp);
> - return __xfs_btree_updkeys(cur, level, block, bp, false);
> -}
> -
> /* Update all the keys from some level in cursor back to the root. */
> STATIC int
> xfs_btree_updkeys_force(
> @@ -2163,7 +2131,7 @@ xfs_btree_updkeys_force(
> /*
> * Update the parent keys of the given level, progressing towards the root.
> */
> -int
> +STATIC int
> xfs_btree_update_keys(
> struct xfs_btree_cur *cur,
> int level)
> @@ -2174,20 +2142,21 @@ xfs_btree_update_keys(
> union xfs_btree_key key;
> int ptr;
>
> - ASSERT(!(cur->bc_flags & XFS_BTREE_OVERLAPPING));
> + ASSERT(level >= 0);
> +
> + block = xfs_btree_get_block(cur, level, &bp);
> + if (cur->bc_flags & XFS_BTREE_OVERLAPPING)
> + return __xfs_btree_updkeys(cur, level, block, bp, false);
>
> XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
> XFS_BTREE_TRACE_ARGIK(cur, level, keyp);
>
> - ASSERT(level >= 0);
> -
> /*
> * Go up the tree from this level toward the root.
> * At each level, update the key value to the value input.
> * Stop when we reach a level where the cursor isn't pointing
> * at the first entry in the block.
> */
> - block = xfs_btree_get_block(cur, level, &bp);
> xfs_btree_get_keys(cur, block, &key);
> for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
> #ifdef DEBUG
> @@ -2257,7 +2226,7 @@ xfs_btree_update(
>
> /* Pass new key value up to our parent. */
> if (xfs_btree_needs_key_update(cur, ptr)) {
> - error = cur->bc_ops->update_keys(cur, 0);
> + error = xfs_btree_update_keys(cur, 0);
> if (error)
> goto error0;
> }
> @@ -2447,13 +2416,13 @@ xfs_btree_lshift(
> goto error1;
>
> /* Update the parent keys of the right block. */
> - error = cur->bc_ops->update_keys(cur, level);
> + error = xfs_btree_update_keys(cur, level);
> if (error)
> goto error1;
>
> /* Update the parent high keys of the left block, if needed. */
> if (tcur->bc_flags & XFS_BTREE_OVERLAPPING) {
> - error = tcur->bc_ops->update_keys(tcur, level);
> + error = xfs_btree_update_keys(tcur, level);
> if (error)
> goto error1;
> }
> @@ -2633,13 +2602,13 @@ xfs_btree_rshift(
>
> /* Update the parent high keys of the left block, if needed. */
> if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
> - error = cur->bc_ops->update_keys(cur, level);
> + error = xfs_btree_update_keys(cur, level);
> if (error)
> goto error1;
> }
>
> /* Update the parent keys of the right block. */
> - error = cur->bc_ops->update_keys(tcur, level);
> + error = xfs_btree_update_keys(tcur, level);
> if (error)
> goto error1;
>
> @@ -2778,7 +2747,7 @@ __xfs_btree_split(
> xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
>
> /* Stash the keys of the new block for later insertion. */
> - cur->bc_ops->get_node_keys(cur, right, key);
> + xfs_btree_get_node_keys(cur, right, key);
> } else {
> /* It's a leaf. Move records. */
> union xfs_btree_rec *lrp; /* left record pointer */
> @@ -2792,7 +2761,7 @@ __xfs_btree_split(
> xfs_btree_log_recs(cur, rbp, 1, rrecs);
>
> /* Stash the keys of the new block for later insertion. */
> - cur->bc_ops->get_leaf_keys(cur, right, key);
> + xfs_btree_get_leaf_keys(cur, right, key);
> }
>
> /*
> @@ -2822,7 +2791,7 @@ __xfs_btree_split(
>
> /* Update the parent high keys of the left block, if needed. */
> if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
> - error = cur->bc_ops->update_keys(cur, level);
> + error = xfs_btree_update_keys(cur, level);
> if (error)
> goto error0;
> }
> @@ -3143,9 +3112,9 @@ xfs_btree_new_root(
> * Get the keys for the left block's keys and put them directly
> * in the parent block. Do the same for the right block.
> */
> - cur->bc_ops->get_node_keys(cur, left,
> + xfs_btree_get_node_keys(cur, left,
> xfs_btree_key_addr(cur, 1, new));
> - cur->bc_ops->get_node_keys(cur, right,
> + xfs_btree_get_node_keys(cur, right,
> xfs_btree_key_addr(cur, 2, new));
> } else {
> /*
> @@ -3153,9 +3122,9 @@ xfs_btree_new_root(
> * directly in the parent block. Do the same for the right
> * block.
> */
> - cur->bc_ops->get_leaf_keys(cur, left,
> + xfs_btree_get_leaf_keys(cur, left,
> xfs_btree_key_addr(cur, 1, new));
> - cur->bc_ops->get_leaf_keys(cur, right,
> + xfs_btree_get_leaf_keys(cur, right,
> xfs_btree_key_addr(cur, 2, new));
> }
> xfs_btree_log_keys(cur, nbp, 1, 2);
> @@ -3434,7 +3403,7 @@ xfs_btree_insrec(
> if (bp && bp->b_bn != old_bn) {
> xfs_btree_get_keys(cur, block, lkey);
> } else if (xfs_btree_needs_key_update(cur, optr)) {
> - error = cur->bc_ops->update_keys(cur, level);
> + error = xfs_btree_update_keys(cur, level);
> if (error)
> goto error0;
> }
> @@ -3880,7 +3849,7 @@ xfs_btree_delrec(
> * key values above us in the tree.
> */
> if (xfs_btree_needs_key_update(cur, ptr)) {
> - error = cur->bc_ops->update_keys(cur, level);
> + error = xfs_btree_update_keys(cur, level);
> if (error)
> goto error0;
> }
> diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> index 9b6d628..04d0865 100644
> --- a/fs/xfs/libxfs/xfs_btree.h
> +++ b/fs/xfs/libxfs/xfs_btree.h
> @@ -214,19 +214,6 @@ struct xfs_btree_ops {
> union xfs_btree_rec *r1,
> union xfs_btree_rec *r2);
> #endif
> -
> - /* derive the low & high keys from the records in a leaf block */
> - void (*get_leaf_keys)(struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block,
> - union xfs_btree_key *key);
> -
> - /* derive the low & high keys from the keys in a node block */
> - void (*get_node_keys)(struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block,
> - union xfs_btree_key *key);
> -
> - /* update the parent keys of given btree level */
> - int (*update_keys)(struct xfs_btree_cur *cur, int level);
> };
>
> /*
> @@ -527,17 +514,6 @@ bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs);
> uint xfs_btree_compute_maxlevels(struct xfs_mount *mp, uint *limits,
> unsigned long len);
>
> -void xfs_btree_get_leaf_keys(struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block, union xfs_btree_key *key);
> -void xfs_btree_get_node_keys(struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block, union xfs_btree_key *key);
> -int xfs_btree_update_keys(struct xfs_btree_cur *cur, int level);
> -void xfs_btree_get_leaf_keys_overlapped(struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block, union xfs_btree_key *key);
> -void xfs_btree_get_node_keys_overlapped(struct xfs_btree_cur *cur,
> - struct xfs_btree_block *block, union xfs_btree_key *key);
> -int xfs_btree_update_keys_overlapped(struct xfs_btree_cur *cur, int level);
> -
> /* return codes */
> #define XFS_BTREE_QUERY_RANGE_CONTINUE 0 /* keep iterating */
> #define XFS_BTREE_QUERY_RANGE_ABORT 1 /* stop iterating */
> diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
> index c83691e..31ca220 100644
> --- a/fs/xfs/libxfs/xfs_ialloc_btree.c
> +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
> @@ -320,10 +320,6 @@ static const struct xfs_btree_ops xfs_inobt_ops = {
> .keys_inorder = xfs_inobt_keys_inorder,
> .recs_inorder = xfs_inobt_recs_inorder,
> #endif
> -
> - .get_leaf_keys = xfs_btree_get_leaf_keys,
> - .get_node_keys = xfs_btree_get_node_keys,
> - .update_keys = xfs_btree_update_keys,
> };
>
> static const struct xfs_btree_ops xfs_finobt_ops = {
> @@ -345,10 +341,6 @@ static const struct xfs_btree_ops xfs_finobt_ops = {
> .keys_inorder = xfs_inobt_keys_inorder,
> .recs_inorder = xfs_inobt_recs_inorder,
> #endif
> -
> - .get_leaf_keys = xfs_btree_get_leaf_keys,
> - .get_node_keys = xfs_btree_get_node_keys,
> - .update_keys = xfs_btree_update_keys,
> };
>
> /*
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
> index 232450c..bc1faeb 100644
> --- a/fs/xfs/libxfs/xfs_rmap_btree.c
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.c
> @@ -453,10 +453,6 @@ static const struct xfs_btree_ops xfs_rmapbt_ops = {
> .keys_inorder = xfs_rmapbt_keys_inorder,
> .recs_inorder = xfs_rmapbt_recs_inorder,
> #endif
> -
> - .get_leaf_keys = xfs_btree_get_leaf_keys_overlapped,
> - .get_node_keys = xfs_btree_get_node_keys_overlapped,
> - .update_keys = xfs_btree_update_keys_overlapped,
> };
>
> /*