Btrfs: deal with space cache errors better

Currently if the space cache inode generation number doesn't match the
generation number in the space cache header we will just fail to load the space
cache, but we won't mark the space cache as an error, so we'll keep getting that
error each time somebody tries to cache that block group until we actually clear
the thing.  Fix this by marking the space cache as having an error so we only
get the message once.  This patch also makes it so that we don't try and setup
space cache for a block group that isn't cached, since we won't be able to write
it out anyway.  None of these problems are actual problems, they are just
annoying and sub-optimal.  Thanks,

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

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index ddaf6340fe7f75017a463cc78ae2314b597747d6..8c56f5b389489207760dc027f6a1d8ee8721f9d9 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2742,6 +2742,7 @@ static int cache_save_setup(struct btrfs_block_group_cache *block_group,
        struct btrfs_root *root = block_group->fs_info->tree_root;
        struct inode *inode = NULL;
        u64 alloc_hint = 0;
+       int dcs = BTRFS_DC_ERROR;
        int num_pages = 0;
        int retries = 0;
        int ret = 0;
@@ -2796,6 +2797,8 @@ again:
 
        spin_lock(&block_group->lock);
        if (block_group->cached != BTRFS_CACHE_FINISHED) {
+               /* We're not cached, don't bother trying to write stuff out */
+               dcs = BTRFS_DC_WRITTEN;
                spin_unlock(&block_group->lock);
                goto out_put;
        }
@@ -2822,6 +2825,8 @@ again:
        ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
                                              num_pages, num_pages,
                                              &alloc_hint);
+       if (!ret)
+               dcs = BTRFS_DC_SETUP;
        btrfs_free_reserved_data_space(inode, num_pages);
 out_put:
        iput(inode);
@@ -2829,10 +2834,7 @@ out_free:
        btrfs_release_path(root, path);
 out:
        spin_lock(&block_group->lock);
-       if (ret)
-               block_group->disk_cache_state = BTRFS_DC_ERROR;
-       else
-               block_group->disk_cache_state = BTRFS_DC_SETUP;
+       block_group->disk_cache_state = dcs;
        spin_unlock(&block_group->lock);
 
        return ret;

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 22ee0dc2e6b8a712900c68a8c44df4a453fb86f0..60d684266959bbf8f96c14873e9a1f57e069a29e 100644 (file)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -290,7 +290,7 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
                       (unsigned long long)BTRFS_I(inode)->generation,
                       (unsigned long long)generation,
                       (unsigned long long)block_group->key.objectid);
-               goto out;
+               goto free_cache;
        }
 
        if (!num_entries)
@@ -524,6 +524,12 @@ int btrfs_write_out_cache(struct btrfs_root *root,
                return 0;
        }
 
+       node = rb_first(&block_group->free_space_offset);
+       if (!node) {
+               iput(inode);
+               return 0;
+       }
+
        last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
        filemap_write_and_wait(inode->i_mapping);
        btrfs_wait_ordered_range(inode, inode->i_size &
@@ -543,10 +549,6 @@ int btrfs_write_out_cache(struct btrfs_root *root,
         */
        first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
 
-       node = rb_first(&block_group->free_space_offset);
-       if (!node)
-               goto out_free;
-
        /*
         * Lock all pages first so we can lock the extent safely.
         *