[PATCH] ceph: move ceph_find_inode() outside the s_mutex

[Yan, Zheng]

ceph_find_inode() may wait on freeing inode, using it inside the s_mutex
may cause deadlock. (the freeing inode is waiting for OSD read reply, but
dispatch thread is blocked by the s_mutex)

Signed-off-by: Yan, Zheng <***@redhat.com>
---
fs/ceph/caps.c | 11 ++++++-----
fs/ceph/mds_client.c | 7 ++++---
2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 6d1cd45..b3b0a91 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3045,6 +3045,12 @@ void ceph_handle_caps(struct ceph_mds_session *session,
}
}

+ /* lookup ino */
+ inode = ceph_find_inode(sb, vino);
+ ci = ceph_inode(inode);
+ dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
+ vino.snap, inode);
+
mutex_lock(&session->s_mutex);
session->s_seq++;
dout(" mds%d seq %lld cap seq %u\n", session->s_mds, session->s_seq,
@@ -3053,11 +3059,6 @@ void ceph_handle_caps(struct ceph_mds_session *session,
if (op == CEPH_CAP_OP_IMPORT)
ceph_add_cap_releases(mdsc, session);

- /* lookup ino */
- inode = ceph_find_inode(sb, vino);
- ci = ceph_inode(inode);
- dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
- vino.snap, inode);
if (!inode) {
dout(" i don't have ino %llx\n", vino.ino);

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 80d9f07..c27e204 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2947,14 +2947,15 @@ static void handle_lease(struct ceph_mds_client *mdsc,
if (dname.len != get_unaligned_le32(h+1))
goto bad;

- mutex_lock(&session->s_mutex);
- session->s_seq++;
-
/* lookup inode */
inode = ceph_find_inode(sb, vino);
dout("handle_lease %s, ino %llx %p %.*s\n",
ceph_lease_op_name(h->action), vino.ino, inode,
dname.len, dname.name);
+
+ mutex_lock(&session->s_mutex);
+ session->s_seq++;
+
if (inode == NULL) {
dout("handle_lease no inode %llx\n", vino.ino);
goto release;

[Sage Weil]

Post by Yan, Zheng
ceph_find_inode() may wait on freeing inode, using it inside the s_mutex
may cause deadlock. (the freeing inode is waiting for OSD read reply, but
dispatch thread is blocked by the s_mutex)
---
fs/ceph/caps.c | 11 ++++++-----
fs/ceph/mds_client.c | 7 ++++---
2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 6d1cd45..b3b0a91 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3045,6 +3045,12 @@ void ceph_handle_caps(struct ceph_mds_session *session,
}
}
+ /* lookup ino */
+ inode = ceph_find_inode(sb, vino);
+ ci = ceph_inode(inode);
+ dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
+ vino.snap, inode);
+
mutex_lock(&session->s_mutex);
session->s_seq++;
dout(" mds%d seq %lld cap seq %u\n", session->s_mds, session->s_seq,
@@ -3053,11 +3059,6 @@ void ceph_handle_caps(struct ceph_mds_session *session,
if (op == CEPH_CAP_OP_IMPORT)
ceph_add_cap_releases(mdsc, session);
- /* lookup ino */
- inode = ceph_find_inode(sb, vino);
- ci = ceph_inode(inode);
- dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
- vino.snap, inode);
if (!inode) {
dout(" i don't have ino %llx\n", vino.ino);
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 80d9f07..c27e204 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2947,14 +2947,15 @@ static void handle_lease(struct ceph_mds_client *mdsc,
if (dname.len != get_unaligned_le32(h+1))
goto bad;
- mutex_lock(&session->s_mutex);
- session->s_seq++;
-
/* lookup inode */
inode = ceph_find_inode(sb, vino);
dout("handle_lease %s, ino %llx %p %.*s\n",
ceph_lease_op_name(h->action), vino.ino, inode,
dname.len, dname.name);
+
+ mutex_lock(&session->s_mutex);
+ session->s_seq++;
+
if (inode == NULL) {
dout("handle_lease no inode %llx\n", vino.ino);
goto release;
--
1.9.3
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