From 278f6679f454bf185a07d9a4ca355b153482d17a Mon Sep 17 00:00:00 2001
From: Jeff Mahoney <jeffm@suse.com>
Date: Thu, 8 Aug 2013 17:34:46 -0400
Subject: reiserfs: locking, handle nested locks properly
The reiserfs write lock replaced the BKL and uses similar semantics.
Frederic's locking code makes a distinction between when the lock is nested
and when it's being acquired/released, but I don't think that's the right
distinction to make.
The right distinction is between the lock being released at end-of-use and
the lock being released for a schedule. The unlock should return the depth
and the lock should restore it, rather than the other way around as it is now.
This patch implements that and adds a number of places where the lock
should be dropped.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
fs/reiserfs/fix_node.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
(limited to 'fs/reiserfs/fix_node.c')
diff --git a/fs/reiserfs/fix_node.c b/fs/reiserfs/fix_node.c
index 430e0658704..dc4d4153031 100644
--- a/fs/reiserfs/fix_node.c
+++ b/fs/reiserfs/fix_node.c
@@ -1022,9 +1022,9 @@ static int get_far_parent(struct tree_balance *tb,
if (buffer_locked(*pcom_father)) {
/* Release the write lock while the buffer is busy */
- reiserfs_write_unlock(tb->tb_sb);
+ int depth = reiserfs_write_unlock_nested(tb->tb_sb);
__wait_on_buffer(*pcom_father);
- reiserfs_write_lock(tb->tb_sb);
+ reiserfs_write_lock_nested(tb->tb_sb, depth);
if (FILESYSTEM_CHANGED_TB(tb)) {
brelse(*pcom_father);
return REPEAT_SEARCH;
@@ -1929,9 +1929,9 @@ static int get_direct_parent(struct tree_balance *tb, int h)
return REPEAT_SEARCH;
if (buffer_locked(bh)) {
- reiserfs_write_unlock(tb->tb_sb);
+ int depth = reiserfs_write_unlock_nested(tb->tb_sb);
__wait_on_buffer(bh);
- reiserfs_write_lock(tb->tb_sb);
+ reiserfs_write_lock_nested(tb->tb_sb, depth);
if (FILESYSTEM_CHANGED_TB(tb))
return REPEAT_SEARCH;
}
@@ -1952,6 +1952,7 @@ static int get_neighbors(struct tree_balance *tb, int h)
unsigned long son_number;
struct super_block *sb = tb->tb_sb;
struct buffer_head *bh;
+ int depth;
PROC_INFO_INC(sb, get_neighbors[h]);
@@ -1969,9 +1970,9 @@ static int get_neighbors(struct tree_balance *tb, int h)
tb->FL[h]) ? tb->lkey[h] : B_NR_ITEMS(tb->
FL[h]);
son_number = B_N_CHILD_NUM(tb->FL[h], child_position);
- reiserfs_write_unlock(sb);
+ depth = reiserfs_write_unlock_nested(tb->tb_sb);
bh = sb_bread(sb, son_number);
- reiserfs_write_lock(sb);
+ reiserfs_write_lock_nested(tb->tb_sb, depth);
if (!bh)
return IO_ERROR;
if (FILESYSTEM_CHANGED_TB(tb)) {
@@ -2009,9 +2010,9 @@ static int get_neighbors(struct tree_balance *tb, int h)
child_position =
(bh == tb->FR[h]) ? tb->rkey[h] + 1 : 0;
son_number = B_N_CHILD_NUM(tb->FR[h], child_position);
- reiserfs_write_unlock(sb);
+ depth = reiserfs_write_unlock_nested(tb->tb_sb);
bh = sb_bread(sb, son_number);
- reiserfs_write_lock(sb);
+ reiserfs_write_lock_nested(tb->tb_sb, depth);
if (!bh)
return IO_ERROR;
if (FILESYSTEM_CHANGED_TB(tb)) {
@@ -2272,6 +2273,7 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb)
}
if (locked) {
+ int depth;
#ifdef CONFIG_REISERFS_CHECK
repeat_counter++;
if ((repeat_counter % 10000) == 0) {
@@ -2286,9 +2288,9 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb)
REPEAT_SEARCH : CARRY_ON;
}
#endif
- reiserfs_write_unlock(tb->tb_sb);
+ depth = reiserfs_write_unlock_nested(tb->tb_sb);
__wait_on_buffer(locked);
- reiserfs_write_lock(tb->tb_sb);
+ reiserfs_write_lock_nested(tb->tb_sb, depth);
if (FILESYSTEM_CHANGED_TB(tb))
return REPEAT_SEARCH;
}
@@ -2359,9 +2361,9 @@ int fix_nodes(int op_mode, struct tree_balance *tb,
/* if it possible in indirect_to_direct conversion */
if (buffer_locked(tbS0)) {
- reiserfs_write_unlock(tb->tb_sb);
+ int depth = reiserfs_write_unlock_nested(tb->tb_sb);
__wait_on_buffer(tbS0);
- reiserfs_write_lock(tb->tb_sb);
+ reiserfs_write_lock_nested(tb->tb_sb, depth);
if (FILESYSTEM_CHANGED_TB(tb))
return REPEAT_SEARCH;
}
--
cgit v1.2.3-70-g09d2