diff options
Diffstat (limited to 'fs/reiserfs/stree.c')
| -rw-r--r-- | fs/reiserfs/stree.c | 53 |
1 files changed, 45 insertions, 8 deletions
diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c index d036ee5b1c81..5fa7118f04e1 100644 --- a/fs/reiserfs/stree.c +++ b/fs/reiserfs/stree.c @@ -222,9 +222,6 @@ static inline int bin_search(const void *key, /* Key to search for. */ return ITEM_NOT_FOUND; } -#ifdef CONFIG_REISERFS_CHECK -extern struct tree_balance *cur_tb; -#endif /* Minimal possible key. It is never in the tree. */ const struct reiserfs_key MIN_KEY = { 0, 0, {{0, 0},} }; @@ -519,25 +516,48 @@ static int is_tree_node(struct buffer_head *bh, int level) #define SEARCH_BY_KEY_READA 16 -/* The function is NOT SCHEDULE-SAFE! */ -static void search_by_key_reada(struct super_block *s, +/* + * The function is NOT SCHEDULE-SAFE! + * It might unlock the write lock if we needed to wait for a block + * to be read. Note that in this case it won't recover the lock to avoid + * high contention resulting from too much lock requests, especially + * the caller (search_by_key) will perform other schedule-unsafe + * operations just after calling this function. + * + * @return true if we have unlocked + */ +static bool search_by_key_reada(struct super_block *s, struct buffer_head **bh, b_blocknr_t *b, int num) { int i, j; + bool unlocked = false; for (i = 0; i < num; i++) { bh[i] = sb_getblk(s, b[i]); } + /* + * We are going to read some blocks on which we + * have a reference. It's safe, though we might be + * reading blocks concurrently changed if we release + * the lock. But it's still fine because we check later + * if the tree changed + */ for (j = 0; j < i; j++) { /* * note, this needs attention if we are getting rid of the BKL * you have to make sure the prepared bit isn't set on this buffer */ - if (!buffer_uptodate(bh[j])) + if (!buffer_uptodate(bh[j])) { + if (!unlocked) { + reiserfs_write_unlock(s); + unlocked = true; + } ll_rw_block(READA, 1, bh + j); + } brelse(bh[j]); } + return unlocked; } /************************************************************************** @@ -625,11 +645,26 @@ int search_by_key(struct super_block *sb, const struct cpu_key *key, /* Key to s have a pointer to it. */ if ((bh = last_element->pe_buffer = sb_getblk(sb, block_number))) { + bool unlocked = false; + if (!buffer_uptodate(bh) && reada_count > 1) - search_by_key_reada(sb, reada_bh, + /* may unlock the write lock */ + unlocked = search_by_key_reada(sb, reada_bh, reada_blocks, reada_count); + /* + * If we haven't already unlocked the write lock, + * then we need to do that here before reading + * the current block + */ + if (!buffer_uptodate(bh) && !unlocked) { + reiserfs_write_unlock(sb); + unlocked = true; + } ll_rw_block(READ, 1, &bh); wait_on_buffer(bh); + + if (unlocked) + reiserfs_write_lock(sb); if (!buffer_uptodate(bh)) goto io_error; } else { @@ -673,7 +708,7 @@ int search_by_key(struct super_block *sb, const struct cpu_key *key, /* Key to s !key_in_buffer(search_path, key, sb), "PAP-5130: key is not in the buffer"); #ifdef CONFIG_REISERFS_CHECK - if (cur_tb) { + if (REISERFS_SB(sb)->cur_tb) { print_cur_tb("5140"); reiserfs_panic(sb, "PAP-5140", "schedule occurred in do_balance!"); @@ -1024,7 +1059,9 @@ static char prepare_for_delete_or_cut(struct reiserfs_transaction_handle *th, st reiserfs_free_block(th, inode, block, 1); } + reiserfs_write_unlock(sb); cond_resched(); + reiserfs_write_lock(sb); if (item_moved (&s_ih, path)) { need_re_search = 1; |