From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/ceph/snap.c | 288 +++++++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 249 insertions(+), 39 deletions(-)
diff --git a/kernel/fs/ceph/snap.c b/kernel/fs/ceph/snap.c
index 5cf7b5f..db46468 100644
--- a/kernel/fs/ceph/snap.c
+++ b/kernel/fs/ceph/snap.c
@@ -3,11 +3,13 @@
#include <linux/sort.h>
#include <linux/slab.h>
-
+#include <linux/iversion.h>
#include "super.h"
#include "mds_client.h"
-
#include <linux/ceph/decode.h>
+
+/* unused map expires after 5 minutes */
+#define CEPH_SNAPID_MAP_TIMEOUT (5 * 60 * HZ)
/*
* Snapshots in ceph are driven in large part by cooperation from the
@@ -58,24 +60,26 @@
/*
* increase ref count for the realm
*
- * caller must hold snap_rwsem for write.
+ * caller must hold snap_rwsem.
*/
void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
- dout("get_realm %p %d -> %d\n", realm,
- atomic_read(&realm->nref), atomic_read(&realm->nref)+1);
+ lockdep_assert_held(&mdsc->snap_rwsem);
+
/*
- * since we _only_ increment realm refs or empty the empty
- * list with snap_rwsem held, adjusting the empty list here is
- * safe. we do need to protect against concurrent empty list
- * additions, however.
+ * The 0->1 and 1->0 transitions must take the snap_empty_lock
+ * atomically with the refcount change. Go ahead and bump the
+ * nref here, unless it's 0, in which case we take the spinlock
+ * and then do the increment and remove it from the list.
*/
- if (atomic_inc_return(&realm->nref) == 1) {
- spin_lock(&mdsc->snap_empty_lock);
+ if (atomic_inc_not_zero(&realm->nref))
+ return;
+
+ spin_lock(&mdsc->snap_empty_lock);
+ if (atomic_inc_return(&realm->nref) == 1)
list_del_init(&realm->empty_item);
- spin_unlock(&mdsc->snap_empty_lock);
- }
+ spin_unlock(&mdsc->snap_empty_lock);
}
static void __insert_snap_realm(struct rb_root *root,
@@ -111,6 +115,8 @@
{
struct ceph_snap_realm *realm;
+ lockdep_assert_held_write(&mdsc->snap_rwsem);
+
realm = kzalloc(sizeof(*realm), GFP_NOFS);
if (!realm)
return ERR_PTR(-ENOMEM);
@@ -124,6 +130,8 @@
INIT_LIST_HEAD(&realm->inodes_with_caps);
spin_lock_init(&realm->inodes_with_caps_lock);
__insert_snap_realm(&mdsc->snap_realms, realm);
+ mdsc->num_snap_realms++;
+
dout("create_snap_realm %llx %p\n", realm->ino, realm);
return realm;
}
@@ -131,13 +139,15 @@
/*
* lookup the realm rooted at @ino.
*
- * caller must hold snap_rwsem for write.
+ * caller must hold snap_rwsem.
*/
static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc,
u64 ino)
{
struct rb_node *n = mdsc->snap_realms.rb_node;
struct ceph_snap_realm *r;
+
+ lockdep_assert_held(&mdsc->snap_rwsem);
while (n) {
r = rb_entry(n, struct ceph_snap_realm, node);
@@ -172,9 +182,12 @@
static void __destroy_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
+ lockdep_assert_held_write(&mdsc->snap_rwsem);
+
dout("__destroy_snap_realm %p %llx\n", realm, realm->ino);
rb_erase(&realm->node, &mdsc->snap_realms);
+ mdsc->num_snap_realms--;
if (realm->parent) {
list_del_init(&realm->child_item);
@@ -193,28 +206,30 @@
static void __put_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
- dout("__put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
- atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
+ lockdep_assert_held_write(&mdsc->snap_rwsem);
+
+ /*
+ * We do not require the snap_empty_lock here, as any caller that
+ * increments the value must hold the snap_rwsem.
+ */
if (atomic_dec_and_test(&realm->nref))
__destroy_snap_realm(mdsc, realm);
}
/*
- * caller needn't hold any locks
+ * See comments in ceph_get_snap_realm. Caller needn't hold any locks.
*/
void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
- dout("put_snap_realm %llx %p %d -> %d\n", realm->ino, realm,
- atomic_read(&realm->nref), atomic_read(&realm->nref)-1);
- if (!atomic_dec_and_test(&realm->nref))
+ if (!atomic_dec_and_lock(&realm->nref, &mdsc->snap_empty_lock))
return;
if (down_write_trylock(&mdsc->snap_rwsem)) {
+ spin_unlock(&mdsc->snap_empty_lock);
__destroy_snap_realm(mdsc, realm);
up_write(&mdsc->snap_rwsem);
} else {
- spin_lock(&mdsc->snap_empty_lock);
list_add(&realm->empty_item, &mdsc->snap_empty);
spin_unlock(&mdsc->snap_empty_lock);
}
@@ -230,6 +245,8 @@
static void __cleanup_empty_realms(struct ceph_mds_client *mdsc)
{
struct ceph_snap_realm *realm;
+
+ lockdep_assert_held_write(&mdsc->snap_rwsem);
spin_lock(&mdsc->snap_empty_lock);
while (!list_empty(&mdsc->snap_empty)) {
@@ -263,6 +280,8 @@
u64 parentino)
{
struct ceph_snap_realm *parent;
+
+ lockdep_assert_held_write(&mdsc->snap_rwsem);
if (realm->parent_ino == parentino)
return 0;
@@ -468,6 +487,9 @@
pr_err("ENOMEM allocating ceph_cap_snap on %p\n", inode);
return;
}
+ capsnap->cap_flush.is_capsnap = true;
+ INIT_LIST_HEAD(&capsnap->cap_flush.i_list);
+ INIT_LIST_HEAD(&capsnap->cap_flush.g_list);
spin_lock(&ci->i_ceph_lock);
used = __ceph_caps_used(ci);
@@ -597,13 +619,15 @@
struct ceph_cap_snap *capsnap)
{
struct inode *inode = &ci->vfs_inode;
- struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
+ struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
BUG_ON(capsnap->writing);
capsnap->size = inode->i_size;
capsnap->mtime = inode->i_mtime;
capsnap->atime = inode->i_atime;
capsnap->ctime = inode->i_ctime;
+ capsnap->btime = ci->i_btime;
+ capsnap->change_attr = inode_peek_iversion_raw(inode);
capsnap->time_warp_seq = ci->i_time_warp_seq;
capsnap->truncate_size = ci->i_truncate_size;
capsnap->truncate_seq = ci->i_truncate_seq;
@@ -623,8 +647,10 @@
capsnap->size);
spin_lock(&mdsc->snap_flush_lock);
- if (list_empty(&ci->i_snap_flush_item))
+ if (list_empty(&ci->i_snap_flush_item)) {
+ ihold(inode);
list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);
+ }
spin_unlock(&mdsc->snap_flush_lock);
return 1; /* caller may want to ceph_flush_snaps */
}
@@ -646,13 +672,15 @@
if (!inode)
continue;
spin_unlock(&realm->inodes_with_caps_lock);
- iput(lastinode);
+ /* avoid calling iput_final() while holding
+ * mdsc->snap_rwsem or in mds dispatch threads */
+ ceph_async_iput(lastinode);
lastinode = inode;
ceph_queue_cap_snap(ci);
spin_lock(&realm->inodes_with_caps_lock);
}
spin_unlock(&realm->inodes_with_caps_lock);
- iput(lastinode);
+ ceph_async_iput(lastinode);
dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
}
@@ -671,14 +699,19 @@
struct ceph_mds_snap_realm *ri; /* encoded */
__le64 *snaps; /* encoded */
__le64 *prior_parent_snaps; /* encoded */
- struct ceph_snap_realm *realm = NULL;
+ struct ceph_snap_realm *realm;
struct ceph_snap_realm *first_realm = NULL;
- int invalidate = 0;
+ struct ceph_snap_realm *realm_to_rebuild = NULL;
+ int rebuild_snapcs;
int err = -ENOMEM;
LIST_HEAD(dirty_realms);
+ lockdep_assert_held_write(&mdsc->snap_rwsem);
+
dout("update_snap_trace deletion=%d\n", deletion);
more:
+ realm = NULL;
+ rebuild_snapcs = 0;
ceph_decode_need(&p, e, sizeof(*ri), bad);
ri = p;
p += sizeof(*ri);
@@ -702,7 +735,7 @@
err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));
if (err < 0)
goto fail;
- invalidate += err;
+ rebuild_snapcs += err;
if (le64_to_cpu(ri->seq) > realm->seq) {
dout("update_snap_trace updating %llx %p %lld -> %lld\n",
@@ -727,22 +760,30 @@
if (realm->seq > mdsc->last_snap_seq)
mdsc->last_snap_seq = realm->seq;
- invalidate = 1;
+ rebuild_snapcs = 1;
} else if (!realm->cached_context) {
dout("update_snap_trace %llx %p seq %lld new\n",
realm->ino, realm, realm->seq);
- invalidate = 1;
+ rebuild_snapcs = 1;
} else {
dout("update_snap_trace %llx %p seq %lld unchanged\n",
realm->ino, realm, realm->seq);
}
- dout("done with %llx %p, invalidated=%d, %p %p\n", realm->ino,
- realm, invalidate, p, e);
+ dout("done with %llx %p, rebuild_snapcs=%d, %p %p\n", realm->ino,
+ realm, rebuild_snapcs, p, e);
- /* invalidate when we reach the _end_ (root) of the trace */
- if (invalidate && p >= e)
- rebuild_snap_realms(realm, &dirty_realms);
+ /*
+ * this will always track the uppest parent realm from which
+ * we need to rebuild the snapshot contexts _downward_ in
+ * hierarchy.
+ */
+ if (rebuild_snapcs)
+ realm_to_rebuild = realm;
+
+ /* rebuild_snapcs when we reach the _end_ (root) of the trace */
+ if (realm_to_rebuild && p >= e)
+ rebuild_snap_realms(realm_to_rebuild, &dirty_realms);
if (!first_realm)
first_realm = realm;
@@ -804,7 +845,9 @@
ihold(inode);
spin_unlock(&mdsc->snap_flush_lock);
ceph_flush_snaps(ci, &session);
- iput(inode);
+ /* avoid calling iput_final() while holding
+ * session->s_mutex or in mds dispatch threads */
+ ceph_async_iput(inode);
spin_lock(&mdsc->snap_flush_lock);
}
spin_unlock(&mdsc->snap_flush_lock);
@@ -862,7 +905,7 @@
ceph_snap_op_name(op), split, trace_len);
mutex_lock(&session->s_mutex);
- session->s_seq++;
+ inc_session_sequence(session);
mutex_unlock(&session->s_mutex);
down_write(&mdsc->snap_rwsem);
@@ -948,12 +991,14 @@
ceph_get_snap_realm(mdsc, realm);
ceph_put_snap_realm(mdsc, oldrealm);
- iput(inode);
+ /* avoid calling iput_final() while holding
+ * mdsc->snap_rwsem or mds in dispatch threads */
+ ceph_async_iput(inode);
continue;
skip_inode:
spin_unlock(&ci->i_ceph_lock);
- iput(inode);
+ ceph_async_iput(inode);
}
/* we may have taken some of the old realm's children. */
@@ -965,6 +1010,19 @@
continue;
adjust_snap_realm_parent(mdsc, child, realm->ino);
}
+ } else {
+ /*
+ * In the non-split case both 'num_split_inos' and
+ * 'num_split_realms' should be 0, making this a no-op.
+ * However the MDS happens to populate 'split_realms' list
+ * in one of the UPDATE op cases by mistake.
+ *
+ * Skip both lists just in case to ensure that 'p' is
+ * positioned at the start of realm info, as expected by
+ * ceph_update_snap_trace().
+ */
+ p += sizeof(u64) * num_split_inos;
+ p += sizeof(u64) * num_split_realms;
}
/*
@@ -993,3 +1051,155 @@
up_write(&mdsc->snap_rwsem);
return;
}
+
+struct ceph_snapid_map* ceph_get_snapid_map(struct ceph_mds_client *mdsc,
+ u64 snap)
+{
+ struct ceph_snapid_map *sm, *exist;
+ struct rb_node **p, *parent;
+ int ret;
+
+ exist = NULL;
+ spin_lock(&mdsc->snapid_map_lock);
+ p = &mdsc->snapid_map_tree.rb_node;
+ while (*p) {
+ exist = rb_entry(*p, struct ceph_snapid_map, node);
+ if (snap > exist->snap) {
+ p = &(*p)->rb_left;
+ } else if (snap < exist->snap) {
+ p = &(*p)->rb_right;
+ } else {
+ if (atomic_inc_return(&exist->ref) == 1)
+ list_del_init(&exist->lru);
+ break;
+ }
+ exist = NULL;
+ }
+ spin_unlock(&mdsc->snapid_map_lock);
+ if (exist) {
+ dout("found snapid map %llx -> %x\n", exist->snap, exist->dev);
+ return exist;
+ }
+
+ sm = kmalloc(sizeof(*sm), GFP_NOFS);
+ if (!sm)
+ return NULL;
+
+ ret = get_anon_bdev(&sm->dev);
+ if (ret < 0) {
+ kfree(sm);
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&sm->lru);
+ atomic_set(&sm->ref, 1);
+ sm->snap = snap;
+
+ exist = NULL;
+ parent = NULL;
+ p = &mdsc->snapid_map_tree.rb_node;
+ spin_lock(&mdsc->snapid_map_lock);
+ while (*p) {
+ parent = *p;
+ exist = rb_entry(*p, struct ceph_snapid_map, node);
+ if (snap > exist->snap)
+ p = &(*p)->rb_left;
+ else if (snap < exist->snap)
+ p = &(*p)->rb_right;
+ else
+ break;
+ exist = NULL;
+ }
+ if (exist) {
+ if (atomic_inc_return(&exist->ref) == 1)
+ list_del_init(&exist->lru);
+ } else {
+ rb_link_node(&sm->node, parent, p);
+ rb_insert_color(&sm->node, &mdsc->snapid_map_tree);
+ }
+ spin_unlock(&mdsc->snapid_map_lock);
+ if (exist) {
+ free_anon_bdev(sm->dev);
+ kfree(sm);
+ dout("found snapid map %llx -> %x\n", exist->snap, exist->dev);
+ return exist;
+ }
+
+ dout("create snapid map %llx -> %x\n", sm->snap, sm->dev);
+ return sm;
+}
+
+void ceph_put_snapid_map(struct ceph_mds_client* mdsc,
+ struct ceph_snapid_map *sm)
+{
+ if (!sm)
+ return;
+ if (atomic_dec_and_lock(&sm->ref, &mdsc->snapid_map_lock)) {
+ if (!RB_EMPTY_NODE(&sm->node)) {
+ sm->last_used = jiffies;
+ list_add_tail(&sm->lru, &mdsc->snapid_map_lru);
+ spin_unlock(&mdsc->snapid_map_lock);
+ } else {
+ /* already cleaned up by
+ * ceph_cleanup_snapid_map() */
+ spin_unlock(&mdsc->snapid_map_lock);
+ kfree(sm);
+ }
+ }
+}
+
+void ceph_trim_snapid_map(struct ceph_mds_client *mdsc)
+{
+ struct ceph_snapid_map *sm;
+ unsigned long now;
+ LIST_HEAD(to_free);
+
+ spin_lock(&mdsc->snapid_map_lock);
+ now = jiffies;
+
+ while (!list_empty(&mdsc->snapid_map_lru)) {
+ sm = list_first_entry(&mdsc->snapid_map_lru,
+ struct ceph_snapid_map, lru);
+ if (time_after(sm->last_used + CEPH_SNAPID_MAP_TIMEOUT, now))
+ break;
+
+ rb_erase(&sm->node, &mdsc->snapid_map_tree);
+ list_move(&sm->lru, &to_free);
+ }
+ spin_unlock(&mdsc->snapid_map_lock);
+
+ while (!list_empty(&to_free)) {
+ sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);
+ list_del(&sm->lru);
+ dout("trim snapid map %llx -> %x\n", sm->snap, sm->dev);
+ free_anon_bdev(sm->dev);
+ kfree(sm);
+ }
+}
+
+void ceph_cleanup_snapid_map(struct ceph_mds_client *mdsc)
+{
+ struct ceph_snapid_map *sm;
+ struct rb_node *p;
+ LIST_HEAD(to_free);
+
+ spin_lock(&mdsc->snapid_map_lock);
+ while ((p = rb_first(&mdsc->snapid_map_tree))) {
+ sm = rb_entry(p, struct ceph_snapid_map, node);
+ rb_erase(p, &mdsc->snapid_map_tree);
+ RB_CLEAR_NODE(p);
+ list_move(&sm->lru, &to_free);
+ }
+ spin_unlock(&mdsc->snapid_map_lock);
+
+ while (!list_empty(&to_free)) {
+ sm = list_first_entry(&to_free, struct ceph_snapid_map, lru);
+ list_del(&sm->lru);
+ free_anon_bdev(sm->dev);
+ if (WARN_ON_ONCE(atomic_read(&sm->ref))) {
+ pr_err("snapid map %llx -> %x still in use\n",
+ sm->snap, sm->dev);
+ }
+ kfree(sm);
+ }
+}
--
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