From 8ddc473433b5e8ce8693db9f6e251f5a28267528 Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Mon, 26 Nov 2012 09:25:38 +0000 Subject: [PATCH] Btrfs: fix unprotected defragable inode insertion We forget to get the defrag lock when we re-add the defragable inode, Fix it. Signed-off-by: Miao Xie Signed-off-by: Chris Mason --- fs/btrfs/file.c | 70 ++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 55 insertions(+), 15 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 15117ea..0091832 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -91,7 +91,7 @@ static int __compare_inode_defrag(struct inode_defrag *defrag1, * If an existing record is found the defrag item you * pass in is freed */ -static void __btrfs_add_inode_defrag(struct inode *inode, +static int __btrfs_add_inode_defrag(struct inode *inode, struct inode_defrag *defrag) { struct btrfs_root *root = BTRFS_I(inode)->root; @@ -119,18 +119,24 @@ static void __btrfs_add_inode_defrag(struct inode *inode, entry->transid = defrag->transid; if (defrag->last_offset > entry->last_offset) entry->last_offset = defrag->last_offset; - goto exists; + return -EEXIST; } } set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags); rb_link_node(&defrag->rb_node, parent, p); rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes); - return; + return 0; +} -exists: - kmem_cache_free(btrfs_inode_defrag_cachep, defrag); - return; +static inline int __need_auto_defrag(struct btrfs_root *root) +{ + if (!btrfs_test_opt(root, AUTO_DEFRAG)) + return 0; + + if (btrfs_fs_closing(root->fs_info)) + return 0; + return 1; } /* @@ -143,11 +149,9 @@ int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans, struct btrfs_root *root = BTRFS_I(inode)->root; struct inode_defrag *defrag; u64 transid; + int ret; - if (!btrfs_test_opt(root, AUTO_DEFRAG)) - return 0; - - if (btrfs_fs_closing(root->fs_info)) + if (!__need_auto_defrag(root)) return 0; if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) @@ -167,15 +171,51 @@ int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans, defrag->root = root->root_key.objectid; spin_lock(&root->fs_info->defrag_inodes_lock); - if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) - __btrfs_add_inode_defrag(inode, defrag); - else + if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) { + /* + * If we set IN_DEFRAG flag and evict the inode from memory, + * and then re-read this inode, this new inode doesn't have + * IN_DEFRAG flag. At the case, we may find the existed defrag. + */ + ret = __btrfs_add_inode_defrag(inode, defrag); + if (ret) + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); + } else { kmem_cache_free(btrfs_inode_defrag_cachep, defrag); + } spin_unlock(&root->fs_info->defrag_inodes_lock); return 0; } /* + * Requeue the defrag object. If there is a defrag object that points to + * the same inode in the tree, we will merge them together (by + * __btrfs_add_inode_defrag()) and free the one that we want to requeue. + */ +void btrfs_requeue_inode_defrag(struct inode *inode, + struct inode_defrag *defrag) +{ + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret; + + if (!__need_auto_defrag(root)) + goto out; + + /* + * Here we don't check the IN_DEFRAG flag, because we need merge + * them together. + */ + spin_lock(&root->fs_info->defrag_inodes_lock); + ret = __btrfs_add_inode_defrag(inode, defrag); + spin_unlock(&root->fs_info->defrag_inodes_lock); + if (ret) + goto out; + return; +out: + kmem_cache_free(btrfs_inode_defrag_cachep, defrag); +} + +/* * must be called with the defrag_inodes lock held */ struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, @@ -294,7 +334,7 @@ int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info) */ if (num_defrag == defrag_batch) { defrag->last_offset = range.start; - __btrfs_add_inode_defrag(inode, defrag); + btrfs_requeue_inode_defrag(inode, defrag); /* * we don't want to kfree defrag, we added it back to * the rbtree @@ -308,7 +348,7 @@ int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info) */ defrag->last_offset = 0; defrag->cycled = 1; - __btrfs_add_inode_defrag(inode, defrag); + btrfs_requeue_inode_defrag(inode, defrag); defrag = NULL; } -- 2.7.4