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authorXiubo Li <xiubli@redhat.com>2022-05-10 09:47:01 +0800
committerIlya Dryomov <idryomov@gmail.com>2022-08-03 00:54:12 +0200
commit4868e537fa867f82e38e37429d61d7bb8357d79b (patch)
treebadea4f6181c6755959c8a44c4b84f527da23cad /fs/ceph
parent4f48d5da81ee7004a789c8aac2d0dfb2514c37f1 (diff)
downloadlinux-4868e537fa867f82e38e37429d61d7bb8357d79b.tar.bz2
ceph: wait for the first reply of inflight async unlink
In async unlink case the kclient won't wait for the first reply from MDS and just drop all the links and unhash the dentry and then succeeds immediately. For any new create/link/rename,etc requests followed by using the same file names we must wait for the first reply of the inflight unlink request, or the MDS possibly will fail these following requests with -EEXIST if the inflight async unlink request was delayed for some reasons. And the worst case is that for the none async openc request it will successfully open the file if the CDentry hasn't been unlinked yet, but later the previous delayed async unlink request will remove the CDenty. That means the just created file is possiblly deleted later by accident. We need to wait for the inflight async unlink requests to finish when creating new files/directories by using the same file names. Link: https://tracker.ceph.com/issues/55332 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')
-rw-r--r--fs/ceph/dir.c79
-rw-r--r--fs/ceph/file.c6
-rw-r--r--fs/ceph/mds_client.c75
-rw-r--r--fs/ceph/mds_client.h1
-rw-r--r--fs/ceph/super.c3
-rw-r--r--fs/ceph/super.h19
6 files changed, 167 insertions, 16 deletions
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index eae417d71136..e7e2ebac330d 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -856,6 +856,10 @@ static int ceph_mknod(struct user_namespace *mnt_userns, struct inode *dir,
if (ceph_snap(dir) != CEPH_NOSNAP)
return -EROFS;
+ err = ceph_wait_on_conflict_unlink(dentry);
+ if (err)
+ return err;
+
if (ceph_quota_is_max_files_exceeded(dir)) {
err = -EDQUOT;
goto out;
@@ -918,6 +922,10 @@ static int ceph_symlink(struct user_namespace *mnt_userns, struct inode *dir,
if (ceph_snap(dir) != CEPH_NOSNAP)
return -EROFS;
+ err = ceph_wait_on_conflict_unlink(dentry);
+ if (err)
+ return err;
+
if (ceph_quota_is_max_files_exceeded(dir)) {
err = -EDQUOT;
goto out;
@@ -968,9 +976,13 @@ static int ceph_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
struct ceph_mds_request *req;
struct ceph_acl_sec_ctx as_ctx = {};
- int err = -EROFS;
+ int err;
int op;
+ err = ceph_wait_on_conflict_unlink(dentry);
+ if (err)
+ return err;
+
if (ceph_snap(dir) == CEPH_SNAPDIR) {
/* mkdir .snap/foo is a MKSNAP */
op = CEPH_MDS_OP_MKSNAP;
@@ -980,6 +992,7 @@ static int ceph_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
dout("mkdir dir %p dn %p mode 0%ho\n", dir, dentry, mode);
op = CEPH_MDS_OP_MKDIR;
} else {
+ err = -EROFS;
goto out;
}
@@ -1037,6 +1050,10 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
struct ceph_mds_request *req;
int err;
+ err = ceph_wait_on_conflict_unlink(dentry);
+ if (err)
+ return err;
+
if (ceph_snap(dir) != CEPH_NOSNAP)
return -EROFS;
@@ -1071,9 +1088,27 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
static void ceph_async_unlink_cb(struct ceph_mds_client *mdsc,
struct ceph_mds_request *req)
{
+ struct dentry *dentry = req->r_dentry;
+ struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+ struct ceph_dentry_info *di = ceph_dentry(dentry);
int result = req->r_err ? req->r_err :
le32_to_cpu(req->r_reply_info.head->result);
+ if (!test_bit(CEPH_DENTRY_ASYNC_UNLINK_BIT, &di->flags))
+ pr_warn("%s dentry %p:%pd async unlink bit is not set\n",
+ __func__, dentry, dentry);
+
+ spin_lock(&fsc->async_unlink_conflict_lock);
+ hash_del_rcu(&di->hnode);
+ spin_unlock(&fsc->async_unlink_conflict_lock);
+
+ spin_lock(&dentry->d_lock);
+ di->flags &= ~CEPH_DENTRY_ASYNC_UNLINK;
+ wake_up_bit(&di->flags, CEPH_DENTRY_ASYNC_UNLINK_BIT);
+ spin_unlock(&dentry->d_lock);
+
+ synchronize_rcu();
+
if (result == -EJUKEBOX)
goto out;
@@ -1081,7 +1116,7 @@ static void ceph_async_unlink_cb(struct ceph_mds_client *mdsc,
if (result) {
int pathlen = 0;
u64 base = 0;
- char *path = ceph_mdsc_build_path(req->r_dentry, &pathlen,
+ char *path = ceph_mdsc_build_path(dentry, &pathlen,
&base, 0);
/* mark error on parent + clear complete */
@@ -1089,13 +1124,13 @@ static void ceph_async_unlink_cb(struct ceph_mds_client *mdsc,
ceph_dir_clear_complete(req->r_parent);
/* drop the dentry -- we don't know its status */
- if (!d_unhashed(req->r_dentry))
- d_drop(req->r_dentry);
+ if (!d_unhashed(dentry))
+ d_drop(dentry);
/* mark inode itself for an error (since metadata is bogus) */
mapping_set_error(req->r_old_inode->i_mapping, result);
- pr_warn("ceph: async unlink failure path=(%llx)%s result=%d!\n",
+ pr_warn("async unlink failure path=(%llx)%s result=%d!\n",
base, IS_ERR(path) ? "<<bad>>" : path, result);
ceph_mdsc_free_path(path, pathlen);
}
@@ -1180,6 +1215,8 @@ retry:
if (try_async && op == CEPH_MDS_OP_UNLINK &&
(req->r_dir_caps = get_caps_for_async_unlink(dir, dentry))) {
+ struct ceph_dentry_info *di = ceph_dentry(dentry);
+
dout("async unlink on %llu/%.*s caps=%s", ceph_ino(dir),
dentry->d_name.len, dentry->d_name.name,
ceph_cap_string(req->r_dir_caps));
@@ -1187,6 +1224,16 @@ retry:
req->r_callback = ceph_async_unlink_cb;
req->r_old_inode = d_inode(dentry);
ihold(req->r_old_inode);
+
+ spin_lock(&dentry->d_lock);
+ di->flags |= CEPH_DENTRY_ASYNC_UNLINK;
+ spin_unlock(&dentry->d_lock);
+
+ spin_lock(&fsc->async_unlink_conflict_lock);
+ hash_add_rcu(fsc->async_unlink_conflict, &di->hnode,
+ dentry->d_name.hash);
+ spin_unlock(&fsc->async_unlink_conflict_lock);
+
err = ceph_mdsc_submit_request(mdsc, dir, req);
if (!err) {
/*
@@ -1195,10 +1242,20 @@ retry:
*/
drop_nlink(inode);
d_delete(dentry);
- } else if (err == -EJUKEBOX) {
- try_async = false;
- ceph_mdsc_put_request(req);
- goto retry;
+ } else {
+ spin_lock(&fsc->async_unlink_conflict_lock);
+ hash_del_rcu(&di->hnode);
+ spin_unlock(&fsc->async_unlink_conflict_lock);
+
+ spin_lock(&dentry->d_lock);
+ di->flags &= ~CEPH_DENTRY_ASYNC_UNLINK;
+ spin_unlock(&dentry->d_lock);
+
+ if (err == -EJUKEBOX) {
+ try_async = false;
+ ceph_mdsc_put_request(req);
+ goto retry;
+ }
}
} else {
set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
@@ -1237,6 +1294,10 @@ static int ceph_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
(!ceph_quota_is_same_realm(old_dir, new_dir)))
return -EXDEV;
+ err = ceph_wait_on_conflict_unlink(new_dentry);
+ if (err)
+ return err;
+
dout("rename dir %p dentry %p to dir %p dentry %p\n",
old_dir, old_dentry, new_dir, new_dentry);
req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index da59e836a06e..0f3424dc618b 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -569,7 +569,7 @@ static void ceph_async_create_cb(struct ceph_mds_client *mdsc,
char *path = ceph_mdsc_build_path(req->r_dentry, &pathlen,
&base, 0);
- pr_warn("ceph: async create failure path=(%llx)%s result=%d!\n",
+ pr_warn("async create failure path=(%llx)%s result=%d!\n",
base, IS_ERR(path) ? "<<bad>>" : path, result);
ceph_mdsc_free_path(path, pathlen);
@@ -740,6 +740,10 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
if (dentry->d_name.len > NAME_MAX)
return -ENAMETOOLONG;
+ err = ceph_wait_on_conflict_unlink(dentry);
+ if (err)
+ return err;
+
if (flags & O_CREAT) {
if (ceph_quota_is_max_files_exceeded(dir))
return -EDQUOT;
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 0aded10375fd..f6da80d110dc 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -456,7 +456,7 @@ static int ceph_parse_deleg_inos(void **p, void *end,
dout("added delegated inode 0x%llx\n",
start - 1);
} else if (err == -EBUSY) {
- pr_warn("ceph: MDS delegated inode 0x%llx more than once.\n",
+ pr_warn("MDS delegated inode 0x%llx more than once.\n",
start - 1);
} else {
return err;
@@ -655,6 +655,79 @@ static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
free_pages((unsigned long)info->dir_entries, get_order(info->dir_buf_size));
}
+/*
+ * In async unlink case the kclient won't wait for the first reply
+ * from MDS and just drop all the links and unhash the dentry and then
+ * succeeds immediately.
+ *
+ * For any new create/link/rename,etc requests followed by using the
+ * same file names we must wait for the first reply of the inflight
+ * unlink request, or the MDS possibly will fail these following
+ * requests with -EEXIST if the inflight async unlink request was
+ * delayed for some reasons.
+ *
+ * And the worst case is that for the none async openc request it will
+ * successfully open the file if the CDentry hasn't been unlinked yet,
+ * but later the previous delayed async unlink request will remove the
+ * CDenty. That means the just created file is possiblly deleted later
+ * by accident.
+ *
+ * We need to wait for the inflight async unlink requests to finish
+ * when creating new files/directories by using the same file names.
+ */
+int ceph_wait_on_conflict_unlink(struct dentry *dentry)
+{
+ struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
+ struct dentry *pdentry = dentry->d_parent;
+ struct dentry *udentry, *found = NULL;
+ struct ceph_dentry_info *di;
+ struct qstr dname;
+ u32 hash = dentry->d_name.hash;
+ int err;
+
+ dname.name = dentry->d_name.name;
+ dname.len = dentry->d_name.len;
+
+ rcu_read_lock();
+ hash_for_each_possible_rcu(fsc->async_unlink_conflict, di,
+ hnode, hash) {
+ udentry = di->dentry;
+
+ spin_lock(&udentry->d_lock);
+ if (udentry->d_name.hash != hash)
+ goto next;
+ if (unlikely(udentry->d_parent != pdentry))
+ goto next;
+ if (!hash_hashed(&di->hnode))
+ goto next;
+
+ if (!test_bit(CEPH_DENTRY_ASYNC_UNLINK_BIT, &di->flags))
+ pr_warn("%s dentry %p:%pd async unlink bit is not set\n",
+ __func__, dentry, dentry);
+
+ if (!d_same_name(udentry, pdentry, &dname))
+ goto next;
+
+ spin_unlock(&udentry->d_lock);
+ found = dget(udentry);
+ break;
+next:
+ spin_unlock(&udentry->d_lock);
+ }
+ rcu_read_unlock();
+
+ if (likely(!found))
+ return 0;
+
+ dout("%s dentry %p:%pd conflict with old %p:%pd\n", __func__,
+ dentry, dentry, found, found);
+
+ err = wait_on_bit(&di->flags, CEPH_DENTRY_ASYNC_UNLINK_BIT,
+ TASK_KILLABLE);
+ dput(found);
+ return err;
+}
+
/*
* sessions
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 4620167f58eb..d8ec2ac93da3 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -575,6 +575,7 @@ static inline int ceph_wait_on_async_create(struct inode *inode)
TASK_KILLABLE);
}
+extern int ceph_wait_on_conflict_unlink(struct dentry *dentry);
extern u64 ceph_get_deleg_ino(struct ceph_mds_session *session);
extern int ceph_restore_deleg_ino(struct ceph_mds_session *session, u64 ino);
#endif
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 40140805bdcf..5539f6c87a45 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -816,6 +816,9 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
if (!fsc->cap_wq)
goto fail_inode_wq;
+ hash_init(fsc->async_unlink_conflict);
+ spin_lock_init(&fsc->async_unlink_conflict_lock);
+
spin_lock(&ceph_fsc_lock);
list_add_tail(&fsc->metric_wakeup, &ceph_fsc_list);
spin_unlock(&ceph_fsc_lock);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index f59dac66955b..59469253592b 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -19,6 +19,7 @@
#include <linux/security.h>
#include <linux/netfs.h>
#include <linux/fscache.h>
+#include <linux/hashtable.h>
#include <linux/ceph/libceph.h>
@@ -99,6 +100,8 @@ struct ceph_mount_options {
char *mon_addr;
};
+#define CEPH_ASYNC_CREATE_CONFLICT_BITS 8
+
struct ceph_fs_client {
struct super_block *sb;
@@ -124,6 +127,9 @@ struct ceph_fs_client {
struct workqueue_struct *inode_wq;
struct workqueue_struct *cap_wq;
+ DECLARE_HASHTABLE(async_unlink_conflict, CEPH_ASYNC_CREATE_CONFLICT_BITS);
+ spinlock_t async_unlink_conflict_lock;
+
#ifdef CONFIG_DEBUG_FS
struct dentry *debugfs_dentry_lru, *debugfs_caps;
struct dentry *debugfs_congestion_kb;
@@ -280,7 +286,8 @@ struct ceph_dentry_info {
struct dentry *dentry;
struct ceph_mds_session *lease_session;
struct list_head lease_list;
- unsigned flags;
+ struct hlist_node hnode;
+ unsigned long flags;
int lease_shared_gen;
u32 lease_gen;
u32 lease_seq;
@@ -289,10 +296,12 @@ struct ceph_dentry_info {
u64 offset;
};
-#define CEPH_DENTRY_REFERENCED 1
-#define CEPH_DENTRY_LEASE_LIST 2
-#define CEPH_DENTRY_SHRINK_LIST 4
-#define CEPH_DENTRY_PRIMARY_LINK 8
+#define CEPH_DENTRY_REFERENCED (1 << 0)
+#define CEPH_DENTRY_LEASE_LIST (1 << 1)
+#define CEPH_DENTRY_SHRINK_LIST (1 << 2)
+#define CEPH_DENTRY_PRIMARY_LINK (1 << 3)
+#define CEPH_DENTRY_ASYNC_UNLINK_BIT (4)
+#define CEPH_DENTRY_ASYNC_UNLINK (1 << CEPH_DENTRY_ASYNC_UNLINK_BIT)
struct ceph_inode_xattrs_info {
/*