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authorStefan Behrens <sbehrens@giantdisaster.de>2013-09-05 16:58:43 +0200
committerChris Mason <chris.mason@fusionio.com>2013-11-11 21:49:26 -0500
commit69e9c6c6dc87587d8846e447febedefe037c14f8 (patch)
tree557fc35afdf3bbee9ce0f46a2ce16ce1c386133c /fs/btrfs/inode.c
parent5e01dc7b26d9f24f39abace5da98ccbd6a5ceb52 (diff)
downloadop-kernel-dev-69e9c6c6dc87587d8846e447febedefe037c14f8.zip
op-kernel-dev-69e9c6c6dc87587d8846e447febedefe037c14f8.tar.gz
Btrfs: eliminate the exceptional root_tree refs=0
The fact that btrfs_root_refs() returned 0 for the tree_root caused bugs in the past, therefore it is set to 1 with this patch and (hopefully) all affected code is adapted to this change. I verified this change by temporarily adding WARN_ON() checks everywhere where btrfs_root_refs() is used, checking whether the logic of the code is changed by btrfs_root_refs() returning 1 instead of 0 for root->root_key.objectid == BTRFS_ROOT_TREE_OBJECTID. With these added checks, I ran the xfstests './check -g auto'. The two roots chunk_root and log_root_tree that are only referenced by the superblock and the log_roots below the log_root_tree still have btrfs_root_refs() == 0, only the tree_root is changed. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/inode.c')
-rw-r--r--fs/btrfs/inode.c21
1 files changed, 8 insertions, 13 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 51e3afa..dfc60aa 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4472,8 +4472,10 @@ void btrfs_evict_inode(struct inode *inode)
trace_btrfs_inode_evict(inode);
truncate_inode_pages(&inode->i_data, 0);
- if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
- btrfs_is_free_space_inode(inode)))
+ if (inode->i_nlink &&
+ ((btrfs_root_refs(&root->root_item) != 0 &&
+ root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
+ btrfs_is_free_space_inode(inode)))
goto no_delete;
if (is_bad_inode(inode)) {
@@ -4490,7 +4492,8 @@ void btrfs_evict_inode(struct inode *inode)
}
if (inode->i_nlink > 0) {
- BUG_ON(btrfs_root_refs(&root->root_item) != 0);
+ BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
+ root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
goto no_delete;
}
@@ -4731,14 +4734,7 @@ static void inode_tree_del(struct inode *inode)
}
spin_unlock(&root->inode_lock);
- /*
- * Free space cache has inodes in the tree root, but the tree root has a
- * root_refs of 0, so this could end up dropping the tree root as a
- * snapshot, so we need the extra !root->fs_info->tree_root check to
- * make sure we don't drop it.
- */
- if (empty && btrfs_root_refs(&root->root_item) == 0 &&
- root != root->fs_info->tree_root) {
+ if (empty && btrfs_root_refs(&root->root_item) == 0) {
synchronize_srcu(&root->fs_info->subvol_srcu);
spin_lock(&root->inode_lock);
empty = RB_EMPTY_ROOT(&root->inode_tree);
@@ -7857,8 +7853,7 @@ int btrfs_drop_inode(struct inode *inode)
return 1;
/* the snap/subvol tree is on deleting */
- if (btrfs_root_refs(&root->root_item) == 0 &&
- root != root->fs_info->tree_root)
+ if (btrfs_root_refs(&root->root_item) == 0)
return 1;
else
return generic_drop_inode(inode);
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