[Ocfs2-devel] [PATCH v2] ocfs2: fix ocfs2 read inode data panic in ocfs2_iget
Shuning Zhang
sunny.s.zhang at oracle.com
Mon Apr 1 23:18:39 PDT 2019
In some cases, the function ocfs2_iget read 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
Changes in v2:
- add description of reporducing this issue
- use ocfs2_test_inode_bit instead of i_dtime
Signed-off-by: Shuning Zhang <sunny.s.zhang at oracle.com>
---
fs/ocfs2/export.c | 30 +++++++++++++++++++++++++++++-
1 files changed, 29 insertions(+), 1 deletions(-)
diff --git a/fs/ocfs2/export.c b/fs/ocfs2/export.c
index 827fc98..da17aa6 100644
--- a/fs/ocfs2/export.c
+++ b/fs/ocfs2/export.c
@@ -148,16 +148,24 @@ static struct dentry *ocfs2_get_parent(struct dentry *child)
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(struct dentry *child)
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);
--
1.7.1
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