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authorJeff Mahoney <jeffm@suse.com>2014-04-23 10:00:36 -0400
committerJan Kara <jack@suse.cz>2014-05-06 22:52:19 +0200
commit098297b27d23ad9d0fc302e3417474d9342c6c14 (patch)
tree58f2054cd9933225ef1ae9c7febedc9160041af6 /fs/reiserfs/do_balan.c
parent4cf5f7addf18ecae2ea49b11944976cbd26d5281 (diff)
downloadop-kernel-dev-098297b27d23ad9d0fc302e3417474d9342c6c14.zip
op-kernel-dev-098297b27d23ad9d0fc302e3417474d9342c6c14.tar.gz
reiserfs: cleanup, reformat comments to normal kernel style
This patch reformats comments in the reiserfs code to fit in 80 columns and to follow the style rules. There is no functional change but it helps make my eyes bleed less. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/reiserfs/do_balan.c')
-rw-r--r--fs/reiserfs/do_balan.c276
1 files changed, 154 insertions, 122 deletions
diff --git a/fs/reiserfs/do_balan.c b/fs/reiserfs/do_balan.c
index 80b2b1b..399b200 100644
--- a/fs/reiserfs/do_balan.c
+++ b/fs/reiserfs/do_balan.c
@@ -2,18 +2,13 @@
* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
-/* Now we have all buffers that must be used in balancing of the tree */
-/* Further calculations can not cause schedule(), and thus the buffer */
-/* tree will be stable until the balancing will be finished */
-/* balance the tree according to the analysis made before, */
-/* and using buffers obtained after all above. */
-
-/**
- ** balance_leaf_when_delete
- ** balance_leaf
- ** do_balance
- **
- **/
+/*
+ * Now we have all buffers that must be used in balancing of the tree
+ * Further calculations can not cause schedule(), and thus the buffer
+ * tree will be stable until the balancing will be finished
+ * balance the tree according to the analysis made before,
+ * and using buffers obtained after all above.
+ */
#include <asm/uaccess.h>
#include <linux/time.h>
@@ -68,35 +63,39 @@ inline void do_balance_mark_leaf_dirty(struct tree_balance *tb,
#define do_balance_mark_internal_dirty do_balance_mark_leaf_dirty
#define do_balance_mark_sb_dirty do_balance_mark_leaf_dirty
-/* summary:
- if deleting something ( tb->insert_size[0] < 0 )
- return(balance_leaf_when_delete()); (flag d handled here)
- else
- if lnum is larger than 0 we put items into the left node
- if rnum is larger than 0 we put items into the right node
- if snum1 is larger than 0 we put items into the new node s1
- if snum2 is larger than 0 we put items into the new node s2
-Note that all *num* count new items being created.
-
-It would be easier to read balance_leaf() if each of these summary
-lines was a separate procedure rather than being inlined. I think
-that there are many passages here and in balance_leaf_when_delete() in
-which two calls to one procedure can replace two passages, and it
-might save cache space and improve software maintenance costs to do so.
-
-Vladimir made the perceptive comment that we should offload most of
-the decision making in this function into fix_nodes/check_balance, and
-then create some sort of structure in tb that says what actions should
-be performed by do_balance.
-
--Hans */
-
-/* Balance leaf node in case of delete or cut: insert_size[0] < 0
+/*
+ * summary:
+ * if deleting something ( tb->insert_size[0] < 0 )
+ * return(balance_leaf_when_delete()); (flag d handled here)
+ * else
+ * if lnum is larger than 0 we put items into the left node
+ * if rnum is larger than 0 we put items into the right node
+ * if snum1 is larger than 0 we put items into the new node s1
+ * if snum2 is larger than 0 we put items into the new node s2
+ * Note that all *num* count new items being created.
+ *
+ * It would be easier to read balance_leaf() if each of these summary
+ * lines was a separate procedure rather than being inlined. I think
+ * that there are many passages here and in balance_leaf_when_delete() in
+ * which two calls to one procedure can replace two passages, and it
+ * might save cache space and improve software maintenance costs to do so.
+ *
+ * Vladimir made the perceptive comment that we should offload most of
+ * the decision making in this function into fix_nodes/check_balance, and
+ * then create some sort of structure in tb that says what actions should
+ * be performed by do_balance.
+ *
+ * -Hans
+ */
+
+/*
+ * Balance leaf node in case of delete or cut: insert_size[0] < 0
*
* lnum, rnum can have values >= -1
* -1 means that the neighbor must be joined with S
* 0 means that nothing should be done with the neighbor
- * >0 means to shift entirely or partly the specified number of items to the neighbor
+ * >0 means to shift entirely or partly the specified number of items
+ * to the neighbor
*/
static int balance_leaf_when_delete(struct tree_balance *tb, int flag)
{
@@ -149,8 +148,16 @@ static int balance_leaf_when_delete(struct tree_balance *tb, int flag)
case M_CUT:{ /* cut item in S[0] */
if (is_direntry_le_ih(ih)) {
- /* UFS unlink semantics are such that you can only delete one directory entry at a time. */
- /* when we cut a directory tb->insert_size[0] means number of entries to be cut (always 1) */
+ /*
+ * UFS unlink semantics are such that you
+ * can only delete one directory entry at
+ * a time.
+ */
+
+ /*
+ * when we cut a directory tb->insert_size[0]
+ * means number of entries to be cut (always 1)
+ */
tb->insert_size[0] = -1;
leaf_cut_from_buffer(&bi, item_pos, pos_in_item,
-tb->insert_size[0]);
@@ -183,13 +190,22 @@ static int balance_leaf_when_delete(struct tree_balance *tb, int flag)
"UNKNOWN"), flag);
}
- /* the rule is that no shifting occurs unless by shifting a node can be freed */
+ /*
+ * the rule is that no shifting occurs unless by shifting
+ * a node can be freed
+ */
n = B_NR_ITEMS(tbS0);
- if (tb->lnum[0]) { /* L[0] takes part in balancing */
- if (tb->lnum[0] == -1) { /* L[0] must be joined with S[0] */
- if (tb->rnum[0] == -1) { /* R[0] must be also joined with S[0] */
+ /* L[0] takes part in balancing */
+ if (tb->lnum[0]) {
+ /* L[0] must be joined with S[0] */
+ if (tb->lnum[0] == -1) {
+ /* R[0] must be also joined with S[0] */
+ if (tb->rnum[0] == -1) {
if (tb->FR[0] == PATH_H_PPARENT(tb->tb_path, 0)) {
- /* all contents of all the 3 buffers will be in L[0] */
+ /*
+ * all contents of all the 3 buffers
+ * will be in L[0]
+ */
if (PATH_H_POSITION(tb->tb_path, 1) == 0
&& 1 < B_NR_ITEMS(tb->FR[0]))
replace_key(tb, tb->CFL[0],
@@ -208,7 +224,10 @@ static int balance_leaf_when_delete(struct tree_balance *tb, int flag)
return 0;
}
- /* all contents of all the 3 buffers will be in R[0] */
+ /*
+ * all contents of all the 3 buffers will
+ * be in R[0]
+ */
leaf_move_items(LEAF_FROM_S_TO_R, tb, n, -1,
NULL);
leaf_move_items(LEAF_FROM_L_TO_R, tb,
@@ -233,7 +252,11 @@ static int balance_leaf_when_delete(struct tree_balance *tb, int flag)
return 0;
}
- /* a part of contents of S[0] will be in L[0] and the rest part of S[0] will be in R[0] */
+
+ /*
+ * a part of contents of S[0] will be in L[0] and the
+ * rest part of S[0] will be in R[0]
+ */
RFALSE((tb->lnum[0] + tb->rnum[0] < n) ||
(tb->lnum[0] + tb->rnum[0] > n + 1),
@@ -1178,9 +1201,7 @@ struct buffer_head *get_FEB(struct tree_balance *tb)
return tb->used[i];
}
-/* This is now used because reiserfs_free_block has to be able to
-** schedule.
-*/
+/* This is now used because reiserfs_free_block has to be able to schedule. */
static void store_thrown(struct tree_balance *tb, struct buffer_head *bh)
{
int i;
@@ -1335,8 +1356,10 @@ static int check_before_balancing(struct tree_balance *tb)
"mount point.");
}
- /* double check that buffers that we will modify are unlocked. (fix_nodes should already have
- prepped all of these for us). */
+ /*
+ * double check that buffers that we will modify are unlocked.
+ * (fix_nodes should already have prepped all of these for us).
+ */
if (tb->lnum[0]) {
retval |= locked_or_not_in_tree(tb, tb->L[0], "L[0]");
retval |= locked_or_not_in_tree(tb, tb->FL[0], "FL[0]");
@@ -1429,49 +1452,51 @@ static void check_internal_levels(struct tree_balance *tb)
#endif
-/* Now we have all of the buffers that must be used in balancing of
- the tree. We rely on the assumption that schedule() will not occur
- while do_balance works. ( Only interrupt handlers are acceptable.)
- We balance the tree according to the analysis made before this,
- using buffers already obtained. For SMP support it will someday be
- necessary to add ordered locking of tb. */
-
-/* Some interesting rules of balancing:
-
- we delete a maximum of two nodes per level per balancing: we never
- delete R, when we delete two of three nodes L, S, R then we move
- them into R.
-
- we only delete L if we are deleting two nodes, if we delete only
- one node we delete S
-
- if we shift leaves then we shift as much as we can: this is a
- deliberate policy of extremism in node packing which results in
- higher average utilization after repeated random balance operations
- at the cost of more memory copies and more balancing as a result of
- small insertions to full nodes.
-
- if we shift internal nodes we try to evenly balance the node
- utilization, with consequent less balancing at the cost of lower
- utilization.
-
- one could argue that the policy for directories in leaves should be
- that of internal nodes, but we will wait until another day to
- evaluate this.... It would be nice to someday measure and prove
- these assumptions as to what is optimal....
+/*
+ * Now we have all of the buffers that must be used in balancing of
+ * the tree. We rely on the assumption that schedule() will not occur
+ * while do_balance works. ( Only interrupt handlers are acceptable.)
+ * We balance the tree according to the analysis made before this,
+ * using buffers already obtained. For SMP support it will someday be
+ * necessary to add ordered locking of tb.
+ */
-*/
+/*
+ * Some interesting rules of balancing:
+ * we delete a maximum of two nodes per level per balancing: we never
+ * delete R, when we delete two of three nodes L, S, R then we move
+ * them into R.
+ *
+ * we only delete L if we are deleting two nodes, if we delete only
+ * one node we delete S
+ *
+ * if we shift leaves then we shift as much as we can: this is a
+ * deliberate policy of extremism in node packing which results in
+ * higher average utilization after repeated random balance operations
+ * at the cost of more memory copies and more balancing as a result of
+ * small insertions to full nodes.
+ *
+ * if we shift internal nodes we try to evenly balance the node
+ * utilization, with consequent less balancing at the cost of lower
+ * utilization.
+ *
+ * one could argue that the policy for directories in leaves should be
+ * that of internal nodes, but we will wait until another day to
+ * evaluate this.... It would be nice to someday measure and prove
+ * these assumptions as to what is optimal....
+ */
static inline void do_balance_starts(struct tree_balance *tb)
{
- /* use print_cur_tb() to see initial state of struct
- tree_balance */
+ /* use print_cur_tb() to see initial state of struct tree_balance */
/* store_print_tb (tb); */
/* do not delete, just comment it out */
-/* print_tb(flag, PATH_LAST_POSITION(tb->tb_path), tb->tb_path->pos_in_item, tb,
- "check");*/
+ /*
+ print_tb(flag, PATH_LAST_POSITION(tb->tb_path),
+ tb->tb_path->pos_in_item, tb, "check");
+ */
RFALSE(check_before_balancing(tb), "PAP-12340: locked buffers in TB");
#ifdef CONFIG_REISERFS_CHECK
REISERFS_SB(tb->tb_sb)->cur_tb = tb;
@@ -1487,9 +1512,10 @@ static inline void do_balance_completed(struct tree_balance *tb)
REISERFS_SB(tb->tb_sb)->cur_tb = NULL;
#endif
- /* reiserfs_free_block is no longer schedule safe. So, we need to
- ** put the buffers we want freed on the thrown list during do_balance,
- ** and then free them now
+ /*
+ * reiserfs_free_block is no longer schedule safe. So, we need to
+ * put the buffers we want freed on the thrown list during do_balance,
+ * and then free them now
*/
REISERFS_SB(tb->tb_sb)->s_do_balance++;
@@ -1500,36 +1526,40 @@ static inline void do_balance_completed(struct tree_balance *tb)
free_thrown(tb);
}
-void do_balance(struct tree_balance *tb, /* tree_balance structure */
- struct item_head *ih, /* item header of inserted item */
- const char *body, /* body of inserted item or bytes to paste */
- int flag)
-{ /* i - insert, d - delete
- c - cut, p - paste
-
- Cut means delete part of an item
- (includes removing an entry from a
- directory).
-
- Delete means delete whole item.
-
- Insert means add a new item into the
- tree.
-
- Paste means to append to the end of an
- existing file or to insert a directory
- entry. */
- int child_pos, /* position of a child node in its parent */
- h; /* level of the tree being processed */
- struct item_head insert_key[2]; /* in our processing of one level
- we sometimes determine what
- must be inserted into the next
- higher level. This insertion
- consists of a key or two keys
- and their corresponding
- pointers */
- struct buffer_head *insert_ptr[2]; /* inserted node-ptrs for the next
- level */
+/*
+ * do_balance - balance the tree
+ *
+ * @tb: tree_balance structure
+ * @ih: item header of inserted item
+ * @body: body of inserted item or bytes to paste
+ * @flag: 'i' - insert, 'd' - delete, 'c' - cut, 'p' paste
+ *
+ * Cut means delete part of an item (includes removing an entry from a
+ * directory).
+ *
+ * Delete means delete whole item.
+ *
+ * Insert means add a new item into the tree.
+ *
+ * Paste means to append to the end of an existing file or to
+ * insert a directory entry.
+ */
+void do_balance(struct tree_balance *tb, struct item_head *ih,
+ const char *body, int flag)
+{
+ int child_pos; /* position of a child node in its parent */
+ int h; /* level of the tree being processed */
+
+ /*
+ * in our processing of one level we sometimes determine what
+ * must be inserted into the next higher level. This insertion
+ * consists of a key or two keys and their corresponding
+ * pointers
+ */
+ struct item_head insert_key[2];
+
+ /* inserted node-ptrs for the next level */
+ struct buffer_head *insert_ptr[2];
tb->tb_mode = flag;
tb->need_balance_dirty = 0;
@@ -1549,9 +1579,11 @@ void do_balance(struct tree_balance *tb, /* tree_balance structure */
atomic_inc(&(fs_generation(tb->tb_sb)));
do_balance_starts(tb);
- /* balance leaf returns 0 except if combining L R and S into
- one node. see balance_internal() for explanation of this
- line of code. */
+ /*
+ * balance_leaf returns 0 except if combining L R and S into
+ * one node. see balance_internal() for explanation of this
+ * line of code.
+ */
child_pos = PATH_H_B_ITEM_ORDER(tb->tb_path, 0) +
balance_leaf(tb, ih, body, flag, insert_key, insert_ptr);
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