Btrfs: stop trying to shrink delalloc if there are no inodes to reclaim

In very severe ENOSPC cases we can run out of inodes to do delalloc on, which
means we'll just keep looping trying to shrink delalloc.  Instead, if we fail to
shrink delalloc 3 times in a row break out since we're not likely to make any
progress.  Tested this with a 100mb fs an xfstests test 13.  Before the patch it
would hang the box, with the patch we get -ENOSPC like we should.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 32d094002a57132b2113e9e8f02303f6a8b16052..c6a5d9095d5f0b1024062af19c00aa5b9e460f70 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3115,6 +3115,7 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
        u64 reserved;
        u64 max_reclaim;
        u64 reclaimed = 0;
+       int no_reclaim = 0;
        int pause = 1;
        int ret;
 
@@ -3131,12 +3132,16 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans,
        while (1) {
                ret = btrfs_start_one_delalloc_inode(root, trans ? 1 : 0);
                if (!ret) {
+                       if (no_reclaim > 2)
+                               break;
+                       no_reclaim++;
                        __set_current_state(TASK_INTERRUPTIBLE);
                        schedule_timeout(pause);
                        pause <<= 1;
                        if (pause > HZ / 10)
                                pause = HZ / 10;
                } else {
+                       no_reclaim = 0;
                        pause = 1;
                }