From: Xiubo Li <xiubli@xxxxxxxxxx>
When mounting if the server path has more than one slash, such as:
'mount.ceph 192.168.195.165:40176:/// /mnt/cephfs/'
In the MDS server side the extra slash will be treated as snap dir,
and then we can get the following debug logs:
<7>[ ...] ceph: mount opening path //
<7>[ ...] ceph: open_root_inode opening '//'
<7>[ ...] ceph: fill_trace 0000000059b8a3bc is_dentry 0 is_target 1
<7>[ ...] ceph: alloc_inode 00000000dc4ca00b
<7>[ ...] ceph: get_inode created new inode 00000000dc4ca00b 1.ffffffffffffffff ino 1
<7>[ ...] ceph: get_inode on 1=1.ffffffffffffffff got 00000000dc4ca00b
And then when creating any new file or directory under the mount
point, we can get the following crash core dump:
<4>[ ...] ------------[ cut here ]------------
<2>[ ...] kernel BUG at fs/ceph/inode.c:1347!
<4>[ ...] invalid opcode: 0000 [#1] SMP PTI
<4>[ ...] CPU: 0 PID: 7 Comm: kworker/0:1 Tainted: G E 5.4.0-rc5+ #1
<4>[ ...] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017
<4>[ ...] Workqueue: ceph-msgr ceph_con_workfn [libceph]
<4>[ ...] RIP: 0010:ceph_fill_trace+0x992/0xb30 [ceph]
<4>[ ...] Code: ff 0f 0b 0f 0b 0f 0b 4c 89 fa 48 c7 c6 4d [...]
<4>[ ...] RSP: 0018:ffffa23d40067c70 EFLAGS: 00010297
<4>[ ...] RAX: fffffffffffffffe RBX: ffff8a229eb566c0 RCX: 0000000000000006
<4>[ ...] RDX: 0000000000000000 RSI: 0000000000000092 RDI: ffff8a23aec17900
<4>[ ...] RBP: ffff8a226bd91eb0 R08: 0000000000000001 R09: 0000000000000885
<4>[ ...] R10: 000000000002dfd8 R11: ffff8a226bd95b30 R12: ffff8a239347e000
<4>[ ...] R13: 0000000000000000 R14: ffff8a22fabeb000 R15: ffff8a2338b0c900
<4>[ ...] FS: 0000000000000000(0000) GS:ffff8a23aec00000(0000) knlGS:0000000000000000
<4>[ ...] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[ ...] CR2: 000055b479d92068 CR3: 00000003764f6004 CR4: 00000000003606f0
<4>[ ...] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<4>[ ...] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
<4>[ ...] Call Trace:
<4>[ ...] dispatch+0x2ac/0x12b0 [ceph]
<4>[ ...] ceph_con_workfn+0xd40/0x27c0 [libceph]
<4>[ ...] process_one_work+0x1b0/0x350
<4>[ ...] worker_thread+0x50/0x3b0
<4>[ ...] kthread+0xfb/0x130
<4>[ ...] ? process_one_work+0x350/0x350
<4>[ ...] ? kthread_park+0x90/0x90
<4>[ ...] ret_from_fork+0x35/0x40
<4>[ ...] Modules linked in: ceph(E) libceph fscache [...]
<4>[ ...] ---[ end trace ba883d8ccf9afcb0 ]---
<4>[ ...] RIP: 0010:ceph_fill_trace+0x992/0xb30 [ceph]
<4>[ ...] Code: ff 0f 0b 0f 0b 0f 0b 4c 89 fa 48 c7 c6 [...]
<4>[ ...] RSP: 0018:ffffa23d40067c70 EFLAGS: 00010297
<4>[ ...] RAX: fffffffffffffffe RBX: ffff8a229eb566c0 RCX: 0000000000000006
<4>[ ...] RDX: 0000000000000000 RSI: 0000000000000092 RDI: ffff8a23aec17900
<4>[ ...] RBP: ffff8a226bd91eb0 R08: 0000000000000001 R09: 0000000000000885
<4>[ ...] R10: 000000000002dfd8 R11: ffff8a226bd95b30 R12: ffff8a239347e000
<4>[ ...] R13: 0000000000000000 R14: ffff8a22fabeb000 R15: ffff8a2338b0c900
<4>[ ...] FS: 0000000000000000(0000) GS:ffff8a23aec00000(0000) knlGS:0000000000000000
<4>[ ...] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[ ...] CR2: 000055b479d92068 CR3: 00000003764f6004 CR4: 00000000003606f0
<4>[ ...] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<4>[ ...] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
And we should ignore the extra slashes in the server path when mount
opening in case users have added them by mistake:
"//mydir1///mydir//" --> "mydir1/mydir/"
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
fs/ceph/super.c | 71 ++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 61 insertions(+), 10 deletions(-)
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index b47f43fc2d68..91985c53e611 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -430,6 +430,39 @@ static int strcmp_null(const char *s1, const char *s2)
return strcmp(s1, s2);
}
+static char *path_remove_extra_slash(const char *path)
+{
+ bool last_is_slash;
+ int i, j;
+ int len;
+ char *p;
+
+ if (!path)
+ return NULL;
+
+ len = strlen(path);
+
+ p = kmalloc(len, GFP_NOFS);
+ if (!p)
+ return ERR_PTR(-ENOMEM);
+
+ last_is_slash = false;
+ for (j = 0, i = 0; i < len; i++) {
+ if (path[i] == '/') {
+ if (last_is_slash)
+ continue;
+ last_is_slash = true;
+ } else {
+ last_is_slash = false;
+ }
+ p[j++] = path[i];
+ }
+
+ p[j] = '\0';
+
+ return p;
+}
+
static int compare_mount_options(struct ceph_mount_options *new_fsopt,
struct ceph_options *new_opt,
struct ceph_fs_client *fsc)
@@ -437,6 +470,7 @@ static int compare_mount_options(struct ceph_mount_options *new_fsopt,
struct ceph_mount_options *fsopt1 = new_fsopt;
struct ceph_mount_options *fsopt2 = fsc->mount_options;
int ofs = offsetof(struct ceph_mount_options, snapdir_name);
+ char *p1, *p2;
int ret;
ret = memcmp(fsopt1, fsopt2, ofs);
@@ -449,9 +483,21 @@ static int compare_mount_options(struct ceph_mount_options *new_fsopt,
ret = strcmp_null(fsopt1->mds_namespace, fsopt2->mds_namespace);
if (ret)
return ret;
- ret = strcmp_null(fsopt1->server_path, fsopt2->server_path);
+
+ p1 = path_remove_extra_slash(fsopt1->server_path);
+ if (IS_ERR(p1))
+ return PTR_ERR(p1);
+ p2 = path_remove_extra_slash(fsopt2->server_path);
+ if (IS_ERR(p2)) {
+ kfree(p1);
+ return PTR_ERR(p2);
+ }
+ ret = strcmp_null(p1, p2);
+ kfree(p1);
+ kfree(p2);
if (ret)
return ret;
+
ret = strcmp_null(fsopt1->fscache_uniq, fsopt2->fscache_uniq);
if (ret)
return ret;
@@ -507,12 +553,10 @@ static int parse_mount_options(struct ceph_mount_options **pfsopt,
*/
dev_name_end = strchr(dev_name, '/');
if (dev_name_end) {
- if (strlen(dev_name_end) > 1) {
- fsopt->server_path = kstrdup(dev_name_end, GFP_KERNEL);
- if (!fsopt->server_path) {
- err = -ENOMEM;
- goto out;
- }
+ fsopt->server_path = kstrdup(dev_name_end, GFP_KERNEL);
+ if (!fsopt->server_path) {
+ err = -ENOMEM;
+ goto out;
}
} else {
dev_name_end = dev_name + strlen(dev_name);
@@ -945,7 +989,7 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
mutex_lock(&fsc->client->mount_mutex);
if (!fsc->sb->s_root) {
- const char *path;
+ const char *path, *p;
err = __ceph_open_session(fsc->client, started);
if (err < 0)
goto out;
@@ -957,17 +1001,24 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
goto out;
}
- if (!fsc->mount_options->server_path) {
+ p = path_remove_extra_slash(fsc->mount_options->server_path);
+ if (IS_ERR(p)) {
+ err = PTR_ERR(p);
+ goto out;
+ }
+ /* if the server path is omitted in the dev_name or just '/' */
+ if (!p || (p && strlen(p) == 1)) {
path = "";
dout("mount opening path \\t\n");
} else {
- path = fsc->mount_options->server_path + 1;
+ path = p + 1;
dout("mount opening path %s\n", path);
}
ceph_fs_debugfs_init(fsc);
root = open_root_dentry(fsc, path, started);
+ kfree(p);
if (IS_ERR(root)) {
err = PTR_ERR(root);
goto out;
--
2.21.0
