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Syzbot reports a possible recursive lock in [1]. This happens due to missing lock nesting information. From the logs, we see that a call to hfs_fill_super is made to mount the hfs filesystem. While searching for the root inode, the lock on the catalog btree is grabbed. Then, when the parent of the root isn't found, a call to __hfs_bnode_create is made to create the parent of the root. This eventually leads to a call to hfs_ext_read_extent which grabs a lock on the extents btree. Since the order of locking is catalog btree -> extents btree, this lock hierarchy does not lead to a deadlock. To tell lockdep that this locking is safe, we add nesting notation to distinguish between catalog btrees, extents btrees, and attributes btrees (for HFS+). This has already been done in hfsplus. Link: https://syzkaller.appspot.com/bug?id=f007ef1d7a31a469e3be7aeb0fde0769b18585db [1] Link: https://lkml.kernel.org/r/20210701030756.58760-4-desmondcheongzx@gmail.com Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com> Reported-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com Tested-by: syzbot+b718ec84a87b7e73ade4@syzkaller.appspotmail.com Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
173 lines
5.3 KiB
C
173 lines
5.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* linux/fs/hfs/btree.h
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*
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* Copyright (C) 2001
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* Brad Boyer (flar@allandria.com)
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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*/
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#include "hfs_fs.h"
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typedef int (*btree_keycmp)(const btree_key *, const btree_key *);
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#define NODE_HASH_SIZE 256
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/* B-tree mutex nested subclasses */
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enum hfs_btree_mutex_classes {
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CATALOG_BTREE_MUTEX,
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EXTENTS_BTREE_MUTEX,
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ATTR_BTREE_MUTEX,
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};
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/* A HFS BTree held in memory */
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struct hfs_btree {
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struct super_block *sb;
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struct inode *inode;
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btree_keycmp keycmp;
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u32 cnid;
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u32 root;
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u32 leaf_count;
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u32 leaf_head;
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u32 leaf_tail;
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u32 node_count;
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u32 free_nodes;
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u32 attributes;
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unsigned int node_size;
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unsigned int node_size_shift;
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unsigned int max_key_len;
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unsigned int depth;
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//unsigned int map1_size, map_size;
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struct mutex tree_lock;
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unsigned int pages_per_bnode;
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spinlock_t hash_lock;
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struct hfs_bnode *node_hash[NODE_HASH_SIZE];
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int node_hash_cnt;
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};
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/* A HFS BTree node in memory */
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struct hfs_bnode {
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struct hfs_btree *tree;
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u32 prev;
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u32 this;
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u32 next;
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u32 parent;
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u16 num_recs;
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u8 type;
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u8 height;
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struct hfs_bnode *next_hash;
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unsigned long flags;
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wait_queue_head_t lock_wq;
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atomic_t refcnt;
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unsigned int page_offset;
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struct page *page[];
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};
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#define HFS_BNODE_ERROR 0
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#define HFS_BNODE_NEW 1
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#define HFS_BNODE_DELETED 2
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struct hfs_find_data {
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btree_key *key;
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btree_key *search_key;
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struct hfs_btree *tree;
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struct hfs_bnode *bnode;
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int record;
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int keyoffset, keylength;
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int entryoffset, entrylength;
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};
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/* btree.c */
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extern struct hfs_btree *hfs_btree_open(struct super_block *, u32, btree_keycmp);
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extern void hfs_btree_close(struct hfs_btree *);
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extern void hfs_btree_write(struct hfs_btree *);
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extern int hfs_bmap_reserve(struct hfs_btree *, int);
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extern struct hfs_bnode * hfs_bmap_alloc(struct hfs_btree *);
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extern void hfs_bmap_free(struct hfs_bnode *node);
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/* bnode.c */
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extern void hfs_bnode_read(struct hfs_bnode *, void *, int, int);
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extern u16 hfs_bnode_read_u16(struct hfs_bnode *, int);
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extern u8 hfs_bnode_read_u8(struct hfs_bnode *, int);
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extern void hfs_bnode_read_key(struct hfs_bnode *, void *, int);
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extern void hfs_bnode_write(struct hfs_bnode *, void *, int, int);
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extern void hfs_bnode_write_u16(struct hfs_bnode *, int, u16);
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extern void hfs_bnode_write_u8(struct hfs_bnode *, int, u8);
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extern void hfs_bnode_clear(struct hfs_bnode *, int, int);
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extern void hfs_bnode_copy(struct hfs_bnode *, int,
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struct hfs_bnode *, int, int);
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extern void hfs_bnode_move(struct hfs_bnode *, int, int, int);
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extern void hfs_bnode_dump(struct hfs_bnode *);
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extern void hfs_bnode_unlink(struct hfs_bnode *);
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extern struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *, u32);
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extern struct hfs_bnode *hfs_bnode_find(struct hfs_btree *, u32);
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extern void hfs_bnode_unhash(struct hfs_bnode *);
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extern void hfs_bnode_free(struct hfs_bnode *);
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extern struct hfs_bnode *hfs_bnode_create(struct hfs_btree *, u32);
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extern void hfs_bnode_get(struct hfs_bnode *);
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extern void hfs_bnode_put(struct hfs_bnode *);
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/* brec.c */
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extern u16 hfs_brec_lenoff(struct hfs_bnode *, u16, u16 *);
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extern u16 hfs_brec_keylen(struct hfs_bnode *, u16);
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extern int hfs_brec_insert(struct hfs_find_data *, void *, int);
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extern int hfs_brec_remove(struct hfs_find_data *);
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/* bfind.c */
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extern int hfs_find_init(struct hfs_btree *, struct hfs_find_data *);
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extern void hfs_find_exit(struct hfs_find_data *);
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extern int __hfs_brec_find(struct hfs_bnode *, struct hfs_find_data *);
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extern int hfs_brec_find(struct hfs_find_data *);
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extern int hfs_brec_read(struct hfs_find_data *, void *, int);
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extern int hfs_brec_goto(struct hfs_find_data *, int);
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struct hfs_bnode_desc {
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__be32 next; /* (V) Number of the next node at this level */
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__be32 prev; /* (V) Number of the prev node at this level */
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u8 type; /* (F) The type of node */
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u8 height; /* (F) The level of this node (leaves=1) */
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__be16 num_recs; /* (V) The number of records in this node */
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u16 reserved;
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} __packed;
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#define HFS_NODE_INDEX 0x00 /* An internal (index) node */
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#define HFS_NODE_HEADER 0x01 /* The tree header node (node 0) */
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#define HFS_NODE_MAP 0x02 /* Holds part of the bitmap of used nodes */
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#define HFS_NODE_LEAF 0xFF /* A leaf (ndNHeight==1) node */
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struct hfs_btree_header_rec {
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__be16 depth; /* (V) The number of levels in this B-tree */
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__be32 root; /* (V) The node number of the root node */
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__be32 leaf_count; /* (V) The number of leaf records */
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__be32 leaf_head; /* (V) The number of the first leaf node */
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__be32 leaf_tail; /* (V) The number of the last leaf node */
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__be16 node_size; /* (F) The number of bytes in a node (=512) */
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__be16 max_key_len; /* (F) The length of a key in an index node */
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__be32 node_count; /* (V) The total number of nodes */
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__be32 free_nodes; /* (V) The number of unused nodes */
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u16 reserved1;
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__be32 clump_size; /* (F) clump size. not usually used. */
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u8 btree_type; /* (F) BTree type */
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u8 reserved2;
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__be32 attributes; /* (F) attributes */
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u32 reserved3[16];
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} __packed;
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#define BTREE_ATTR_BADCLOSE 0x00000001 /* b-tree not closed properly. not
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used by hfsplus. */
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#define HFS_TREE_BIGKEYS 0x00000002 /* key length is u16 instead of u8.
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used by hfsplus. */
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#define HFS_TREE_VARIDXKEYS 0x00000004 /* variable key length instead of
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max key length. use din catalog
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b-tree but not in extents
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b-tree (hfsplus). */
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