Gitweb: http://git.kernel.org/linus/148d3504c1d9f964cf14fafc46d2b7d1f0bed2b1
Commit: 148d3504c1d9f964cf14fafc46d2b7d1f0bed2b1
Parent: 5e69e3a4492ea5abfd2e8ddc575448becf28e4d9
Author: Frederic Weisbecker <fweisbec@gmail.com>
AuthorDate: Fri May 1 01:10:52 2009 +0200
Committer: Frederic Weisbecker <fweisbec@gmail.com>
CommitDate: Mon Sep 14 07:18:10 2009 +0200
kill-the-BKL/reiserfs: release the write lock inside get_neighbors()
get_neighbors() is used to get the left and/or right blocks
against a given one in order to balance a tree.
sb_bread() is used to read the buffer of these neighors blocks and
while it waits for this operation, it might sleep.
The bkl was released at this point, and then we can also release
the write lock before calling sb_bread().
This is safe because if the filesystem is changed after this
lock release, the function returns REPEAT_SEARCH (aka SCHEDULE_OCCURRED
in the function header comments) in order to repeat the neighbhor
research.
[ Impact: release the reiserfs write lock when it is not needed ]
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
fs/reiserfs/fix_node.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/fs/reiserfs/fix_node.c b/fs/reiserfs/fix_node.c
index bf5f2cb..3a685e3 100644
--- a/fs/reiserfs/fix_node.c
+++ b/fs/reiserfs/fix_node.c
@@ -1971,7 +1971,9 @@ 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);
bh = sb_bread(sb, son_number);
+ reiserfs_write_lock(sb);
if (!bh)
return IO_ERROR;
if (FILESYSTEM_CHANGED_TB(tb)) {
@@ -2009,7 +2011,9 @@ static int get_neighbors(struct ...
