From: Frederic Weisbecker Date: Thu, 30 Apr 2009 23:10:52 +0000 (+0200) Subject: kill-the-BKL/reiserfs: release the write lock inside get_neighbors() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=148d3504c1d9f964cf14fafc46d2b7d1f0bed2b1;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git 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 Cc: Chris Mason Cc: Alexander Beregalov Signed-off-by: Frederic Weisbecker --- diff --git a/fs/reiserfs/fix_node.c b/fs/reiserfs/fix_node.c index bf5f2cbdb063..3a685e3f754f 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 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); bh = sb_bread(sb, son_number); + reiserfs_write_lock(sb); if (!bh) return IO_ERROR; if (FILESYSTEM_CHANGED_TB(tb)) {