From: Jeff Layton <jlayton@kernel.org>
Date: Mon, 2 Aug 2021 11:01:26 -0400
Subject: ceph: add ceph_change_snap_realm() helper
Git-commit: 0ba92e1c5f7ce7e9c1c828a84e873d7be51c1b9f
Patch-mainline: v5.15-rc1
References: jsc#SES-1880
Consolidate some fiddly code for changing an inode's snap_realm
into a new helper function, and change the callers to use it.
While we're in here, nothing uses the i_snap_realm_counter field, so
remove that from the inode.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
fs/ceph/caps.c | 36 +++--------------------------------
fs/ceph/inode.c | 11 ++---------
fs/ceph/snap.c | 59 ++++++++++++++++++++++++++++++++++++++-------------------
fs/ceph/super.h | 2 +-
4 files changed, 45 insertions(+), 63 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index d5a46556e20e..b75a9e1d6882 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -704,23 +704,7 @@ void ceph_add_cap(struct inode *inode,
struct ceph_snap_realm *realm = ceph_lookup_snap_realm(mdsc,
realmino);
if (realm) {
- struct ceph_snap_realm *oldrealm = ci->i_snap_realm;
- if (oldrealm) {
- spin_lock(&oldrealm->inodes_with_caps_lock);
- list_del_init(&ci->i_snap_realm_item);
- spin_unlock(&oldrealm->inodes_with_caps_lock);
- }
-
- spin_lock(&realm->inodes_with_caps_lock);
- list_add(&ci->i_snap_realm_item,
- &realm->inodes_with_caps);
- ci->i_snap_realm = realm;
- if (realm->ino == ci->i_vino.ino)
- realm->inode = inode;
- spin_unlock(&realm->inodes_with_caps_lock);
-
- if (oldrealm)
- ceph_put_snap_realm(mdsc, oldrealm);
+ ceph_change_snap_realm(inode, realm);
} else {
pr_err("ceph_add_cap: couldn't find snap realm %llx\n",
realmino);
@@ -1112,20 +1096,6 @@ int ceph_is_any_caps(struct inode *inode)
return ret;
}
-static void drop_inode_snap_realm(struct ceph_inode_info *ci)
-{
- struct ceph_snap_realm *realm = ci->i_snap_realm;
- spin_lock(&realm->inodes_with_caps_lock);
- list_del_init(&ci->i_snap_realm_item);
- ci->i_snap_realm_counter++;
- ci->i_snap_realm = NULL;
- if (realm->ino == ci->i_vino.ino)
- realm->inode = NULL;
- spin_unlock(&realm->inodes_with_caps_lock);
- ceph_put_snap_realm(ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc,
- realm);
-}
-
/*
* Remove a cap. Take steps to deal with a racing iterate_session_caps.
*
@@ -1201,7 +1171,7 @@ void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release)
* keep i_snap_realm.
*/
if (ci->i_wr_ref == 0 && ci->i_snap_realm)
- drop_inode_snap_realm(ci);
+ ceph_change_snap_realm(&ci->vfs_inode, NULL);
__cap_delay_cancel(mdsc, ci);
}
@@ -3084,7 +3054,7 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had,
}
/* see comment in __ceph_remove_cap() */
if (!__ceph_is_any_real_caps(ci) && ci->i_snap_realm)
- drop_inode_snap_realm(ci);
+ ceph_change_snap_realm(inode, NULL);
}
}
if (check_flushsnaps && __ceph_have_pending_cap_snap(ci)) {
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 1bd2cc015913..2df1e1284451 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -581,16 +581,9 @@ void ceph_evict_inode(struct inode *inode)
*/
if (ci->i_snap_realm) {
if (ceph_snap(inode) == CEPH_NOSNAP) {
- struct ceph_snap_realm *realm = ci->i_snap_realm;
dout(" dropping residual ref to snap realm %p\n",
- realm);
- spin_lock(&realm->inodes_with_caps_lock);
- list_del_init(&ci->i_snap_realm_item);
- ci->i_snap_realm = NULL;
- if (realm->ino == ci->i_vino.ino)
- realm->inode = NULL;
- spin_unlock(&realm->inodes_with_caps_lock);
- ceph_put_snap_realm(mdsc, realm);
+ ci->i_snap_realm);
+ ceph_change_snap_realm(inode, NULL);
} else {
ceph_put_snapid_map(mdsc, ci->i_snapid_map);
ci->i_snap_realm = NULL;
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 15105f9da3fd..b41e6724c591 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -849,6 +849,43 @@ static void flush_snaps(struct ceph_mds_client *mdsc)
dout("flush_snaps done\n");
}
+/**
+ * ceph_change_snap_realm - change the snap_realm for an inode
+ * @inode: inode to move to new snap realm
+ * @realm: new realm to move inode into (may be NULL)
+ *
+ * Detach an inode from its old snaprealm (if any) and attach it to
+ * the new snaprealm (if any). The old snap realm reference held by
+ * the inode is put. If realm is non-NULL, then the caller's reference
+ * to it is taken over by the inode.
+ */
+void ceph_change_snap_realm(struct inode *inode, struct ceph_snap_realm *realm)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+ struct ceph_snap_realm *oldrealm = ci->i_snap_realm;
+
+ lockdep_assert_held(&ci->i_ceph_lock);
+
+ if (oldrealm) {
+ spin_lock(&oldrealm->inodes_with_caps_lock);
+ list_del_init(&ci->i_snap_realm_item);
+ if (oldrealm->ino == ci->i_vino.ino)
+ oldrealm->inode = NULL;
+ spin_unlock(&oldrealm->inodes_with_caps_lock);
+ ceph_put_snap_realm(mdsc, oldrealm);
+ }
+
+ ci->i_snap_realm = realm;
+
+ if (realm) {
+ spin_lock(&realm->inodes_with_caps_lock);
+ list_add(&ci->i_snap_realm_item, &realm->inodes_with_caps);
+ if (realm->ino == ci->i_vino.ino)
+ realm->inode = inode;
+ spin_unlock(&realm->inodes_with_caps_lock);
+ }
+}
/*
* Handle a snap notification from the MDS.
@@ -935,7 +972,6 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc,
};
struct inode *inode = ceph_find_inode(sb, vino);
struct ceph_inode_info *ci;
- struct ceph_snap_realm *oldrealm;
if (!inode)
continue;
@@ -960,27 +996,10 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc,
}
dout(" will move %p to split realm %llx %p\n",
inode, realm->ino, realm);
- /*
- * Move the inode to the new realm
- */
- oldrealm = ci->i_snap_realm;
- spin_lock(&oldrealm->inodes_with_caps_lock);
- list_del_init(&ci->i_snap_realm_item);
- spin_unlock(&oldrealm->inodes_with_caps_lock);
-
- spin_lock(&realm->inodes_with_caps_lock);
- list_add(&ci->i_snap_realm_item,
- &realm->inodes_with_caps);
- ci->i_snap_realm = realm;
- if (realm->ino == ci->i_vino.ino)
- realm->inode = inode;
- spin_unlock(&realm->inodes_with_caps_lock);
-
- spin_unlock(&ci->i_ceph_lock);
ceph_get_snap_realm(mdsc, realm);
- ceph_put_snap_realm(mdsc, oldrealm);
-
+ ceph_change_snap_realm(inode, realm);
+ spin_unlock(&ci->i_ceph_lock);
iput(inode);
continue;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index b1a363641beb..3fad464d7c6d 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -418,7 +418,6 @@ struct ceph_inode_info {
struct ceph_snap_realm *i_snap_realm; /* snap realm (if caps) */
struct ceph_snapid_map *i_snapid_map; /* snapid -> dev_t */
};
- int i_snap_realm_counter; /* snap realm (if caps) */
struct list_head i_snap_realm_item;
struct list_head i_snap_flush_item;
struct timespec64 i_btime;
@@ -929,6 +928,7 @@ extern void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
extern int ceph_update_snap_trace(struct ceph_mds_client *m,
void *p, void *e, bool deletion,
struct ceph_snap_realm **realm_ret);
+void ceph_change_snap_realm(struct inode *inode, struct ceph_snap_realm *realm);
extern void ceph_handle_snap(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session,
struct ceph_msg *msg);