From: Shuning Zhang sunny.s.zhang@oracle.com Subject: ocfs2: fix ocfs2 read inode data panic in ocfs2_iget

In some cases, ocfs2_iget() reads the data of inode, which has been deleted for some reason. That will make the system panic. So We should judge whether this inode has been deleted, and tell the caller that the inode is a bad inode.

For example, the ocfs2 is used as the backed of nfs, and the client is nfsv3. This issue can be reproduced by the following steps.

on the nfs server side, ..../patha/pathb

Step 1: The process A was scheduled before calling the function fh_verify.

Step 2: The process B is removing the 'pathb', and just completed the call to function dput. Then the dentry of 'pathb' has been deleted from the dcache, and all ancestors have been deleted also. The relationship of dentry and inode was deleted through the function hlist_del_init. The following is the call stack. dentry_iput->hlist_del_init(&dentry->d_u.d_alias)

At this time, the inode is still in the dcache.

Step 3: The process A call the function ocfs2_get_dentry, which get the inode from dcache. Then the refcount of inode is 1. The following is the call stack. nfsd3_proc_getacl->fh_verify->exportfs_decode_fh->fh_to_dentry(ocfs2_get_dentry)

Step 4: Dirty pages are flushed by bdi threads. So the inode of 'patha' is evicted, and this directory was deleted. But the inode of 'pathb' can't be evicted, because the refcount of the inode was 1.

Step 5: The process A keep running, and call the function reconnect_path(in exportfs_decode_fh), which call function ocfs2_get_parent of ocfs2. Get the block number of parent directory(patha) by the name of ... Then read the data from disk by the block number. But this inode has been deleted, so the system panic.

Process A Process B 1. in nfsd3_proc_getacl | 2. | dput 3. fh_to_dentry(ocfs2_get_dentry) | 4. bdi flush dirty cache | 5. ocfs2_iget |

[283465.542049] OCFS2: ERROR (device sdp): ocfs2_validate_inode_block: Invalid dinode #580640: OCFS2_VALID_FL not set

[283465.545490] Kernel panic - not syncing: OCFS2: (device sdp): panic forced after error

[283465.546889] CPU: 5 PID: 12416 Comm: nfsd Tainted: G W 4.1.12-124.18.6.el6uek.bug28762940v3.x86_64 #2 [283465.548382] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 09/21/2015 [283465.549657] 0000000000000000 ffff8800a56fb7b8 ffffffff816e839c ffffffffa0514758 [283465.550392] 000000000008dc20 ffff8800a56fb838 ffffffff816e62d3 0000000000000008 [283465.551056] ffff880000000010 ffff8800a56fb848 ffff8800a56fb7e8 ffff88005df9f000 [283465.551710] Call Trace: [283465.552516] [<ffffffff816e839c>] dump_stack+0x63/0x81 [283465.553291] [<ffffffff816e62d3>] panic+0xcb/0x21b [283465.554037] [<ffffffffa04e66b0>] ocfs2_handle_error+0xf0/0xf0 [ocfs2] [283465.554882] [<ffffffffa04e7737>] __ocfs2_error+0x67/0x70 [ocfs2] [283465.555768] [<ffffffffa049c0f9>] ocfs2_validate_inode_block+0x229/0x230 [ocfs2] [283465.556683] [<ffffffffa047bcbc>] ocfs2_read_blocks+0x46c/0x7b0 [ocfs2] [283465.557408] [<ffffffffa049bed0>] ? ocfs2_inode_cache_io_unlock+0x20/0x20 [ocfs2] [283465.557973] [<ffffffffa049f0eb>] ocfs2_read_inode_block_full+0x3b/0x60 [ocfs2] [283465.558525] [<ffffffffa049f5ba>] ocfs2_iget+0x4aa/0x880 [ocfs2] [283465.559082] [<ffffffffa049146e>] ocfs2_get_parent+0x9e/0x220 [ocfs2] [283465.559622] [<ffffffff81297c05>] reconnect_path+0xb5/0x300 [283465.560156] [<ffffffff81297f46>] exportfs_decode_fh+0xf6/0x2b0 [283465.560708] [<ffffffffa062faf0>] ? nfsd_proc_getattr+0xa0/0xa0 [nfsd] [283465.561262] [<ffffffff810a8196>] ? prepare_creds+0x26/0x110 [283465.561932] [<ffffffffa0630860>] fh_verify+0x350/0x660 [nfsd] [283465.562862] [<ffffffffa0637804>] ? nfsd_cache_lookup+0x44/0x630 [nfsd] [283465.563697] [<ffffffffa063a8b9>] nfsd3_proc_getattr+0x69/0xf0 [nfsd] [283465.564510] [<ffffffffa062cf60>] nfsd_dispatch+0xe0/0x290 [nfsd] [283465.565358] [<ffffffffa05eb892>] ? svc_tcp_adjust_wspace+0x12/0x30 [sunrpc] [283465.566272] [<ffffffffa05ea652>] svc_process_common+0x412/0x6a0 [sunrpc] [283465.567155] [<ffffffffa05eaa03>] svc_process+0x123/0x210 [sunrpc] [283465.568020] [<ffffffffa062c90f>] nfsd+0xff/0x170 [nfsd] [283465.568962] [<ffffffffa062c810>] ? nfsd_destroy+0x80/0x80 [nfsd] [283465.570112] [<ffffffff810a622b>] kthread+0xcb/0xf0 [283465.571099] [<ffffffff810a6160>] ? kthread_create_on_node+0x180/0x180 [283465.572114] [<ffffffff816f11b8>] ret_from_fork+0x58/0x90 [283465.573156] [<ffffffff810a6160>] ? kthread_create_on_node+0x180/0x180

Link: http://lkml.kernel.org/r/1554185919-3010-1-git-send-email-sunny.s.zhang@orac... Signed-off-by: Shuning Zhang sunny.s.zhang@oracle.com Reviewed-by: Joseph Qi jiangqi903@gmail.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: Changwei Ge gechangwei@live.cn Cc: piaojun piaojun@huawei.com Cc: "Gang He" ghe@suse.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/ocfs2/export.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-)

--- a/fs/ocfs2/export.c~ocfs2-fix-ocfs2-read-inode-data-panic-in-ocfs2_iget +++ a/fs/ocfs2/export.c @@ -148,16 +148,24 @@ static struct dentry *ocfs2_get_parent(s u64 blkno; struct dentry *parent; struct inode *dir = d_inode(child); + int set;

trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name, (unsigned long long)OCFS2_I(dir)->ip_blkno);

+ status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1); + if (status < 0) { + mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status); + parent = ERR_PTR(status); + goto bail; + } + status = ocfs2_inode_lock(dir, NULL, 0); if (status < 0) { if (status != -ENOENT) mlog_errno(status); parent = ERR_PTR(status); - goto bail; + goto unlock_nfs_sync; }

status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno); @@ -166,11 +174,31 @@ static struct dentry *ocfs2_get_parent(s goto bail_unlock; }

+ status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set); + if (status < 0) { + if (status == -EINVAL) { + status = -ESTALE; + } else + mlog(ML_ERROR, "test inode bit failed %d\n", status); + parent = ERR_PTR(status); + goto bail_unlock; + } + + trace_ocfs2_get_dentry_test_bit(status, set); + if (!set) { + status = -ESTALE; + parent = ERR_PTR(status); + goto bail_unlock; + } + parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));

bail_unlock: ocfs2_inode_unlock(dir, 0);

+unlock_nfs_sync: + ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1); + bail: trace_ocfs2_get_parent_end(parent);

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