summaryrefslogtreecommitdiffstats
path: root/fs/btrfs/ctree.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/btrfs/ctree.c')
-rw-r--r--fs/btrfs/ctree.c36
1 files changed, 30 insertions, 6 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index a9543f01184c..dcb510f38dda 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -4663,7 +4663,12 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
int ret;
int i;
- ASSERT(!path->nowait);
+ /*
+ * The nowait semantics are used only for write paths, where we don't
+ * use the tree mod log and sequence numbers.
+ */
+ if (time_seq)
+ ASSERT(!path->nowait);
nritems = btrfs_header_nritems(path->nodes[0]);
if (nritems == 0)
@@ -4683,7 +4688,14 @@ again:
if (path->need_commit_sem) {
path->need_commit_sem = 0;
need_commit_sem = true;
- down_read(&fs_info->commit_root_sem);
+ if (path->nowait) {
+ if (!down_read_trylock(&fs_info->commit_root_sem)) {
+ ret = -EAGAIN;
+ goto done;
+ }
+ } else {
+ down_read(&fs_info->commit_root_sem);
+ }
}
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
}
@@ -4759,7 +4771,7 @@ again:
next = c;
ret = read_block_for_search(root, path, &next, level,
slot, &key);
- if (ret == -EAGAIN)
+ if (ret == -EAGAIN && !path->nowait)
goto again;
if (ret < 0) {
@@ -4769,6 +4781,10 @@ again:
if (!path->skip_locking) {
ret = btrfs_try_tree_read_lock(next);
+ if (!ret && path->nowait) {
+ ret = -EAGAIN;
+ goto done;
+ }
if (!ret && time_seq) {
/*
* If we don't get the lock, we may be racing
@@ -4799,7 +4815,7 @@ again:
ret = read_block_for_search(root, path, &next, level,
0, &key);
- if (ret == -EAGAIN)
+ if (ret == -EAGAIN && !path->nowait)
goto again;
if (ret < 0) {
@@ -4807,8 +4823,16 @@ again:
goto done;
}
- if (!path->skip_locking)
- btrfs_tree_read_lock(next);
+ if (!path->skip_locking) {
+ if (path->nowait) {
+ if (!btrfs_try_tree_read_lock(next)) {
+ ret = -EAGAIN;
+ goto done;
+ }
+ } else {
+ btrfs_tree_read_lock(next);
+ }
+ }
}
ret = 0;
done: