btrfs: add helper for fs_info->closing

wrap checking of filesystem 'closing' flag and fix a few missing memory
barriers.

Signed-off-by: David Sterba <dsterba@suse.cz>

8 files changed, 20 insertions, 16 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4958ef5417d6..8490ee063709 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2354,6 +2354,15 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root,
                         struct extent_buffer *node,
                         struct extent_buffer *parent);
+static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
+{
+        /*
+         * Get synced with close_ctree()
+         */
+        smp_mb();
+        return fs_info->closing;
+}
+
 /* root-item.c */
 int btrfs_find_root_ref(struct btrfs_root *tree_root,
                         struct btrfs_path *path,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c9173a7827b0..5b9b6b6df242 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -366,8 +366,7 @@ again:
         nritems = btrfs_header_nritems(leaf);
 
         while (1) {
-                smp_mb();
-                if (fs_info->closing > 1) {
+                if (btrfs_fs_closing(fs_info) > 1) {
                         last = (u64)-1;
                         break;
                 }
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 982b5ea9762f..fa4ef18b66b1 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -129,7 +129,7 @@ int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
         if (!btrfs_test_opt(root, AUTO_DEFRAG))
                 return 0;
 
-        if (root->fs_info->closing)
+        if (btrfs_fs_closing(root->fs_info))
                 return 0;
 
         if (BTRFS_I(inode)->in_defrag)
@@ -229,7 +229,7 @@ int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
                 first_ino = defrag->ino + 1;
                 rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
 
-                if (fs_info->closing)
+                if (btrfs_fs_closing(fs_info))
                         goto next_free;
 
                 spin_unlock(&fs_info->defrag_inodes_lock);
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index bffa5c4a633b..ad144736a5fd 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -98,7 +98,7 @@ struct inode *lookup_free_space_inode(struct btrfs_root *root,
                 return inode;
 
         spin_lock(&block_group->lock);
-        if (!root->fs_info->closing) {
+        if (!btrfs_fs_closing(root->fs_info)) {
                 block_group->inode = igrab(inode);
                 block_group->iref = 1;
         }
@@ -493,8 +493,7 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
          * If we're unmounting then just return, since this does a search on the
          * normal root and not the commit root and we could deadlock.
          */
-        smp_mb();
-        if (fs_info->closing)
+        if (btrfs_fs_closing(fs_info))
                 return 0;
 
         /*
@@ -2513,7 +2512,7 @@ struct inode *lookup_free_ino_inode(struct btrfs_root *root,
                 return inode;
 
         spin_lock(&root->cache_lock);
-        if (!root->fs_info->closing)
+        if (!btrfs_fs_closing(root->fs_info))
                 root->cache_inode = igrab(inode);
         spin_unlock(&root->cache_lock);
 
@@ -2543,8 +2542,7 @@ int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
          * If we're unmounting then just return, since this does a search on the
          * normal root and not the commit root and we could deadlock.
          */
-        smp_mb();
-        if (fs_info->closing)
+        if (btrfs_fs_closing(fs_info))
                 return 0;
 
         path = btrfs_alloc_path();
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index cb79b8975c9f..b4087e0fa871 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -62,8 +62,7 @@ again:
                 goto out;
 
         while (1) {
-                smp_mb();
-                if (fs_info->closing)
+                if (btrfs_fs_closing(fs_info))
                         goto out;
 
                 leaf = path->nodes[0];
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a83e44bf3206..02ff4a1b968b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4266,8 +4266,7 @@ int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
         if (BTRFS_I(inode)->dummy_inode)
                 return 0;
 
-        smp_mb();
-        if (root->fs_info->closing && is_free_space_inode(root, inode))
+        if (btrfs_fs_closing(root->fs_info) && is_free_space_inode(root, inode))
                 nolock = true;
 
         if (wbc->sync_mode == WB_SYNC_ALL) {
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 1204eab94028..df50fd1eca8f 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1183,7 +1183,7 @@ int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
         int ret;
         struct btrfs_device *dev;
 
-        if (root->fs_info->closing)
+        if (btrfs_fs_closing(root->fs_info))
                 return -EINVAL;
 
         /*
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2d5c6d2aa4e4..dd719662340e 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -817,7 +817,7 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
                 btrfs_btree_balance_dirty(info->tree_root, nr);
                 cond_resched();
 
-                if (root->fs_info->closing || ret != -EAGAIN)
+                if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
                         break;
         }
         root->defrag_running = 0;