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nilfs2: remove buffer locking from btree code
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lock_buffer() and unlock_buffer() uses in btree.c are eliminable
because btree functions gain buffer heads through nilfs_btnode_get(),
which never returns an on-the-fly buffer.

Although nilfs_clear_dirty_page() and nilfs_copy_back_pages() in
nilfs_commit_gcdat_inode() juggle btree node buffers of DAT, this is
safe because these operations are protected by a log writer lock or
the metadata file semaphore of DAT.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
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Ryusuke Konishi committed Nov 20, 2009
1 parent a49762f commit 30db4e6
Showing 1 changed file with 0 additions and 60 deletions.
60 changes: 0 additions & 60 deletions fs/nilfs2/btree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -652,13 +652,11 @@ static void nilfs_btree_promote_key(struct nilfs_btree *btree,
{
if (level < nilfs_btree_height(btree) - 1) {
do {
lock_buffer(path[level].bp_bh);
nilfs_btree_node_set_key(
nilfs_btree_get_nonroot_node(path, level),
path[level].bp_index, key);
if (!buffer_dirty(path[level].bp_bh))
nilfs_btnode_mark_dirty(path[level].bp_bh);
unlock_buffer(path[level].bp_bh);
} while ((path[level].bp_index == 0) &&
(++level < nilfs_btree_height(btree) - 1));
}
Expand All @@ -677,13 +675,11 @@ static void nilfs_btree_do_insert(struct nilfs_btree *btree,
struct nilfs_btree_node *node;

if (level < nilfs_btree_height(btree) - 1) {
lock_buffer(path[level].bp_bh);
node = nilfs_btree_get_nonroot_node(path, level);
nilfs_btree_node_insert(btree, node, *keyp, *ptrp,
path[level].bp_index);
if (!buffer_dirty(path[level].bp_bh))
nilfs_btnode_mark_dirty(path[level].bp_bh);
unlock_buffer(path[level].bp_bh);

if (path[level].bp_index == 0)
nilfs_btree_promote_key(btree, path, level + 1,
Expand All @@ -703,9 +699,6 @@ static void nilfs_btree_carry_left(struct nilfs_btree *btree,
struct nilfs_btree_node *node, *left;
int nchildren, lnchildren, n, move;

lock_buffer(path[level].bp_bh);
lock_buffer(path[level].bp_sib_bh);

node = nilfs_btree_get_nonroot_node(path, level);
left = nilfs_btree_get_sib_node(path, level);
nchildren = nilfs_btree_node_get_nchildren(node);
Expand All @@ -726,9 +719,6 @@ static void nilfs_btree_carry_left(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_sib_bh))
nilfs_btnode_mark_dirty(path[level].bp_sib_bh);

unlock_buffer(path[level].bp_bh);
unlock_buffer(path[level].bp_sib_bh);

nilfs_btree_promote_key(btree, path, level + 1,
nilfs_btree_node_get_key(node, 0));

Expand All @@ -754,9 +744,6 @@ static void nilfs_btree_carry_right(struct nilfs_btree *btree,
struct nilfs_btree_node *node, *right;
int nchildren, rnchildren, n, move;

lock_buffer(path[level].bp_bh);
lock_buffer(path[level].bp_sib_bh);

node = nilfs_btree_get_nonroot_node(path, level);
right = nilfs_btree_get_sib_node(path, level);
nchildren = nilfs_btree_node_get_nchildren(node);
Expand All @@ -777,9 +764,6 @@ static void nilfs_btree_carry_right(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_sib_bh))
nilfs_btnode_mark_dirty(path[level].bp_sib_bh);

unlock_buffer(path[level].bp_bh);
unlock_buffer(path[level].bp_sib_bh);

path[level + 1].bp_index++;
nilfs_btree_promote_key(btree, path, level + 1,
nilfs_btree_node_get_key(right, 0));
Expand Down Expand Up @@ -808,9 +792,6 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
__u64 newptr;
int nchildren, n, move;

lock_buffer(path[level].bp_bh);
lock_buffer(path[level].bp_sib_bh);

node = nilfs_btree_get_nonroot_node(path, level);
right = nilfs_btree_get_sib_node(path, level);
nchildren = nilfs_btree_node_get_nchildren(node);
Expand All @@ -829,9 +810,6 @@ static void nilfs_btree_split(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_sib_bh))
nilfs_btnode_mark_dirty(path[level].bp_sib_bh);

unlock_buffer(path[level].bp_bh);
unlock_buffer(path[level].bp_sib_bh);

newkey = nilfs_btree_node_get_key(right, 0);
newptr = path[level].bp_newreq.bpr_ptr;

Expand Down Expand Up @@ -866,8 +844,6 @@ static void nilfs_btree_grow(struct nilfs_btree *btree,
struct nilfs_btree_node *root, *child;
int n;

lock_buffer(path[level].bp_sib_bh);

root = nilfs_btree_get_root(btree);
child = nilfs_btree_get_sib_node(path, level);

Expand All @@ -879,8 +855,6 @@ static void nilfs_btree_grow(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_sib_bh))
nilfs_btnode_mark_dirty(path[level].bp_sib_bh);

unlock_buffer(path[level].bp_sib_bh);

path[level].bp_bh = path[level].bp_sib_bh;
path[level].bp_sib_bh = NULL;

Expand Down Expand Up @@ -1037,11 +1011,9 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,

stats->bs_nblocks++;

lock_buffer(bh);
nilfs_btree_node_init(btree,
(struct nilfs_btree_node *)bh->b_data,
0, level, 0, NULL, NULL);
unlock_buffer(bh);
path[level].bp_sib_bh = bh;
path[level].bp_op = nilfs_btree_split;
}
Expand All @@ -1066,10 +1038,8 @@ static int nilfs_btree_prepare_insert(struct nilfs_btree *btree,
if (ret < 0)
goto err_out_curr_node;

lock_buffer(bh);
nilfs_btree_node_init(btree, (struct nilfs_btree_node *)bh->b_data,
0, level, 0, NULL, NULL);
unlock_buffer(bh);
path[level].bp_sib_bh = bh;
path[level].bp_op = nilfs_btree_grow;

Expand Down Expand Up @@ -1168,13 +1138,11 @@ static void nilfs_btree_do_delete(struct nilfs_btree *btree,
struct nilfs_btree_node *node;

if (level < nilfs_btree_height(btree) - 1) {
lock_buffer(path[level].bp_bh);
node = nilfs_btree_get_nonroot_node(path, level);
nilfs_btree_node_delete(btree, node, keyp, ptrp,
path[level].bp_index);
if (!buffer_dirty(path[level].bp_bh))
nilfs_btnode_mark_dirty(path[level].bp_bh);
unlock_buffer(path[level].bp_bh);
if (path[level].bp_index == 0)
nilfs_btree_promote_key(btree, path, level + 1,
nilfs_btree_node_get_key(node, 0));
Expand All @@ -1194,9 +1162,6 @@ static void nilfs_btree_borrow_left(struct nilfs_btree *btree,

nilfs_btree_do_delete(btree, path, level, keyp, ptrp);

lock_buffer(path[level].bp_bh);
lock_buffer(path[level].bp_sib_bh);

node = nilfs_btree_get_nonroot_node(path, level);
left = nilfs_btree_get_sib_node(path, level);
nchildren = nilfs_btree_node_get_nchildren(node);
Expand All @@ -1211,9 +1176,6 @@ static void nilfs_btree_borrow_left(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_sib_bh))
nilfs_btnode_mark_dirty(path[level].bp_sib_bh);

unlock_buffer(path[level].bp_bh);
unlock_buffer(path[level].bp_sib_bh);

nilfs_btree_promote_key(btree, path, level + 1,
nilfs_btree_node_get_key(node, 0));

Expand All @@ -1231,9 +1193,6 @@ static void nilfs_btree_borrow_right(struct nilfs_btree *btree,

nilfs_btree_do_delete(btree, path, level, keyp, ptrp);

lock_buffer(path[level].bp_bh);
lock_buffer(path[level].bp_sib_bh);

node = nilfs_btree_get_nonroot_node(path, level);
right = nilfs_btree_get_sib_node(path, level);
nchildren = nilfs_btree_node_get_nchildren(node);
Expand All @@ -1248,9 +1207,6 @@ static void nilfs_btree_borrow_right(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_sib_bh))
nilfs_btnode_mark_dirty(path[level].bp_sib_bh);

unlock_buffer(path[level].bp_bh);
unlock_buffer(path[level].bp_sib_bh);

path[level + 1].bp_index++;
nilfs_btree_promote_key(btree, path, level + 1,
nilfs_btree_node_get_key(right, 0));
Expand All @@ -1269,9 +1225,6 @@ static void nilfs_btree_concat_left(struct nilfs_btree *btree,

nilfs_btree_do_delete(btree, path, level, keyp, ptrp);

lock_buffer(path[level].bp_bh);
lock_buffer(path[level].bp_sib_bh);

node = nilfs_btree_get_nonroot_node(path, level);
left = nilfs_btree_get_sib_node(path, level);

Expand All @@ -1282,9 +1235,6 @@ static void nilfs_btree_concat_left(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_sib_bh))
nilfs_btnode_mark_dirty(path[level].bp_sib_bh);

unlock_buffer(path[level].bp_bh);
unlock_buffer(path[level].bp_sib_bh);

nilfs_btnode_delete(path[level].bp_bh);
path[level].bp_bh = path[level].bp_sib_bh;
path[level].bp_sib_bh = NULL;
Expand All @@ -1300,9 +1250,6 @@ static void nilfs_btree_concat_right(struct nilfs_btree *btree,

nilfs_btree_do_delete(btree, path, level, keyp, ptrp);

lock_buffer(path[level].bp_bh);
lock_buffer(path[level].bp_sib_bh);

node = nilfs_btree_get_nonroot_node(path, level);
right = nilfs_btree_get_sib_node(path, level);

Expand All @@ -1313,9 +1260,6 @@ static void nilfs_btree_concat_right(struct nilfs_btree *btree,
if (!buffer_dirty(path[level].bp_bh))
nilfs_btnode_mark_dirty(path[level].bp_bh);

unlock_buffer(path[level].bp_bh);
unlock_buffer(path[level].bp_sib_bh);

nilfs_btnode_delete(path[level].bp_sib_bh);
path[level].bp_sib_bh = NULL;
path[level + 1].bp_index++;
Expand All @@ -1330,15 +1274,13 @@ static void nilfs_btree_shrink(struct nilfs_btree *btree,

nilfs_btree_do_delete(btree, path, level, keyp, ptrp);

lock_buffer(path[level].bp_bh);
root = nilfs_btree_get_root(btree);
child = nilfs_btree_get_nonroot_node(path, level);

nilfs_btree_node_delete(btree, root, NULL, NULL, 0);
nilfs_btree_node_set_level(root, level);
n = nilfs_btree_node_get_nchildren(child);
nilfs_btree_node_move_left(btree, root, child, n);
unlock_buffer(path[level].bp_bh);

nilfs_btnode_delete(path[level].bp_bh);
path[level].bp_bh = NULL;
Expand Down Expand Up @@ -1713,7 +1655,6 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
nilfs_bmap_commit_alloc_ptr(bmap, nreq, dat);

/* create child node at level 1 */
lock_buffer(bh);
node = (struct nilfs_btree_node *)bh->b_data;
nilfs_btree_node_init(btree, node, 0, 1, n, keys, ptrs);
nilfs_btree_node_insert(btree, node,
Expand All @@ -1723,7 +1664,6 @@ nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *bmap,
if (!nilfs_bmap_dirty(bmap))
nilfs_bmap_set_dirty(bmap);

unlock_buffer(bh);
brelse(bh);

/* create root node at level 2 */
Expand Down

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