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authorXiubo Li <xiubli@redhat.com>2022-04-25 11:08:24 +0300
committerIlya Dryomov <idryomov@gmail.com>2022-05-25 21:45:14 +0300
commit825978fd6a0defc3c29d8a38b6cea76a0938d21e (patch)
treee21cd4541b1a6e3bcd0fb1068aa7f3af5dc628d6 /fs/ceph/addr.c
parent3459bd0c55ed28f86a1fd2e01e376492cb6d4f91 (diff)
downloadlinux-825978fd6a0defc3c29d8a38b6cea76a0938d21e.tar.xz
ceph: fix possible deadlock when holding Fwb to get inline_data
1, mount with wsync. 2, create a file with O_RDWR, and the request was sent to mds.0: ceph_atomic_open()--> ceph_mdsc_do_request(openc) finish_open(file, dentry, ceph_open)--> ceph_open()--> ceph_init_file()--> ceph_init_file_info()--> ceph_uninline_data()--> { ... if (inline_version == 1 || /* initial version, no data */ inline_version == CEPH_INLINE_NONE) goto out_unlock; ... } The inline_version will be 1, which is the initial version for the new create file. And here the ci->i_inline_version will keep with 1, it's buggy. 3, buffer write to the file immediately: ceph_write_iter()--> ceph_get_caps(file, need=Fw, want=Fb, ...); generic_perform_write()--> a_ops->write_begin()--> ceph_write_begin()--> netfs_write_begin()--> netfs_begin_read()--> netfs_rreq_submit_slice()--> netfs_read_from_server()--> rreq->netfs_ops->issue_read()--> ceph_netfs_issue_read()--> { ... if (ci->i_inline_version != CEPH_INLINE_NONE && ceph_netfs_issue_op_inline(subreq)) return; ... } ceph_put_cap_refs(ci, Fwb); The ceph_netfs_issue_op_inline() will send a getattr(Fsr) request to mds.1. 4, then the mds.1 will request the rd lock for CInode::filelock from the auth mds.0, the mds.0 will do the CInode::filelock state transation from excl --> sync, but it need to revoke the Fxwb caps back from the clients. While the kernel client has aleady held the Fwb caps and waiting for the getattr(Fsr). It's deadlock! URL: https://tracker.ceph.com/issues/55377 Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph/addr.c')
-rw-r--r--fs/ceph/addr.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 18956c629ad4..1a108f24e7d9 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1648,7 +1648,7 @@ int ceph_uninline_data(struct file *file)
struct inode *inode = file_inode(file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
- struct ceph_osd_request *req;
+ struct ceph_osd_request *req = NULL;
struct ceph_cap_flush *prealloc_cf;
struct folio *folio = NULL;
u64 inline_version = CEPH_INLINE_NONE;
@@ -1656,10 +1656,23 @@ int ceph_uninline_data(struct file *file)
int err = 0;
u64 len;
+ spin_lock(&ci->i_ceph_lock);
+ inline_version = ci->i_inline_version;
+ spin_unlock(&ci->i_ceph_lock);
+
+ dout("uninline_data %p %llx.%llx inline_version %llu\n",
+ inode, ceph_vinop(inode), inline_version);
+
+ if (inline_version == CEPH_INLINE_NONE)
+ return 0;
+
prealloc_cf = ceph_alloc_cap_flush();
if (!prealloc_cf)
return -ENOMEM;
+ if (inline_version == 1) /* initial version, no data */
+ goto out_uninline;
+
folio = read_mapping_folio(inode->i_mapping, 0, file);
if (IS_ERR(folio)) {
err = PTR_ERR(folio);
@@ -1668,17 +1681,6 @@ int ceph_uninline_data(struct file *file)
folio_lock(folio);
- spin_lock(&ci->i_ceph_lock);
- inline_version = ci->i_inline_version;
- spin_unlock(&ci->i_ceph_lock);
-
- dout("uninline_data %p %llx.%llx inline_version %llu\n",
- inode, ceph_vinop(inode), inline_version);
-
- if (inline_version == 1 || /* initial version, no data */
- inline_version == CEPH_INLINE_NONE)
- goto out_unlock;
-
len = i_size_read(inode);
if (len > folio_size(folio))
len = folio_size(folio);
@@ -1743,6 +1745,7 @@ int ceph_uninline_data(struct file *file)
ceph_update_write_metrics(&fsc->mdsc->metric, req->r_start_latency,
req->r_end_latency, len, err);
+out_uninline:
if (!err) {
int dirty;
@@ -1761,8 +1764,10 @@ out_put_req:
if (err == -ECANCELED)
err = 0;
out_unlock:
- folio_unlock(folio);
- folio_put(folio);
+ if (folio) {
+ folio_unlock(folio);
+ folio_put(folio);
+ }
out:
ceph_free_cap_flush(prealloc_cf);
dout("uninline_data %p %llx.%llx inline_version %llu = %d\n",