WSL2-Linux-Kernel/fs/ceph/snap.c

1304 строки
36 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/ceph/ceph_debug.h>
#include <linux/fs.h>
#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
* client. In contrast to local file systems or file servers that
* implement snapshots at a single point in the system, ceph's
* distributed access to storage requires clients to help decide
* whether a write logically occurs before or after a recently created
* snapshot.
*
* This provides a perfect instantanous client-wide snapshot. Between
* clients, however, snapshots may appear to be applied at slightly
* different points in time, depending on delays in delivering the
* snapshot notification.
*
* Snapshots are _not_ file system-wide. Instead, each snapshot
* applies to the subdirectory nested beneath some directory. This
* effectively divides the hierarchy into multiple "realms," where all
* of the files contained by each realm share the same set of
* snapshots. An individual realm's snap set contains snapshots
* explicitly created on that realm, as well as any snaps in its
* parent's snap set _after_ the point at which the parent became it's
* parent (due to, say, a rename). Similarly, snaps from prior parents
* during the time intervals during which they were the parent are included.
*
* The client is spared most of this detail, fortunately... it must only
* maintains a hierarchy of realms reflecting the current parent/child
* realm relationship, and for each realm has an explicit list of snaps
* inherited from prior parents.
*
* A snap_realm struct is maintained for realms containing every inode
* with an open cap in the system. (The needed snap realm information is
* provided by the MDS whenever a cap is issued, i.e., on open.) A 'seq'
* version number is used to ensure that as realm parameters change (new
* snapshot, new parent, etc.) the client's realm hierarchy is updated.
*
* The realm hierarchy drives the generation of a 'snap context' for each
* realm, which simply lists the resulting set of snaps for the realm. This
* is attached to any writes sent to OSDs.
*/
/*
* Unfortunately error handling is a bit mixed here. If we get a snap
* update, but don't have enough memory to update our realm hierarchy,
* it's not clear what we can do about it (besides complaining to the
* console).
*/
/*
* increase ref count for the realm
*
* caller must hold snap_rwsem.
*/
void ceph_get_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
lockdep_assert_held(&mdsc->snap_rwsem);
/*
* 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_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);
}
static void __insert_snap_realm(struct rb_root *root,
struct ceph_snap_realm *new)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct ceph_snap_realm *r = NULL;
while (*p) {
parent = *p;
r = rb_entry(parent, struct ceph_snap_realm, node);
if (new->ino < r->ino)
p = &(*p)->rb_left;
else if (new->ino > r->ino)
p = &(*p)->rb_right;
else
BUG();
}
rb_link_node(&new->node, parent, p);
rb_insert_color(&new->node, root);
}
/*
* create and get the realm rooted at @ino and bump its ref count.
*
* caller must hold snap_rwsem for write.
*/
static struct ceph_snap_realm *ceph_create_snap_realm(
struct ceph_mds_client *mdsc,
u64 ino)
{
struct ceph_snap_realm *realm;
lockdep_assert_held_write(&mdsc->snap_rwsem);
realm = kzalloc(sizeof(*realm), GFP_NOFS);
if (!realm)
return ERR_PTR(-ENOMEM);
/* Do not release the global dummy snaprealm until unmouting */
if (ino == CEPH_INO_GLOBAL_SNAPREALM)
atomic_set(&realm->nref, 2);
else
atomic_set(&realm->nref, 1);
realm->ino = ino;
INIT_LIST_HEAD(&realm->children);
INIT_LIST_HEAD(&realm->child_item);
INIT_LIST_HEAD(&realm->empty_item);
INIT_LIST_HEAD(&realm->dirty_item);
INIT_LIST_HEAD(&realm->rebuild_item);
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("%s %llx %p\n", __func__, realm->ino, realm);
return realm;
}
/*
* lookup the realm rooted at @ino.
*
* 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);
if (ino < r->ino)
n = n->rb_left;
else if (ino > r->ino)
n = n->rb_right;
else {
dout("%s %llx %p\n", __func__, r->ino, r);
return r;
}
}
return NULL;
}
struct ceph_snap_realm *ceph_lookup_snap_realm(struct ceph_mds_client *mdsc,
u64 ino)
{
struct ceph_snap_realm *r;
r = __lookup_snap_realm(mdsc, ino);
if (r)
ceph_get_snap_realm(mdsc, r);
return r;
}
static void __put_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm);
/*
* called with snap_rwsem (write)
*/
static void __destroy_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
lockdep_assert_held_write(&mdsc->snap_rwsem);
dout("%s %p %llx\n", __func__, realm, realm->ino);
rb_erase(&realm->node, &mdsc->snap_realms);
mdsc->num_snap_realms--;
if (realm->parent) {
list_del_init(&realm->child_item);
__put_snap_realm(mdsc, realm->parent);
}
kfree(realm->prior_parent_snaps);
kfree(realm->snaps);
ceph_put_snap_context(realm->cached_context);
kfree(realm);
}
/*
* caller holds snap_rwsem (write)
*/
static void __put_snap_realm(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm)
{
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);
}
/*
* 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)
{
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 {
list_add(&realm->empty_item, &mdsc->snap_empty);
spin_unlock(&mdsc->snap_empty_lock);
}
}
/*
* Clean up any realms whose ref counts have dropped to zero. Note
* that this does not include realms who were created but not yet
* used.
*
* Called under snap_rwsem (write)
*/
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)) {
realm = list_first_entry(&mdsc->snap_empty,
struct ceph_snap_realm, empty_item);
list_del(&realm->empty_item);
spin_unlock(&mdsc->snap_empty_lock);
__destroy_snap_realm(mdsc, realm);
spin_lock(&mdsc->snap_empty_lock);
}
spin_unlock(&mdsc->snap_empty_lock);
}
void ceph_cleanup_global_and_empty_realms(struct ceph_mds_client *mdsc)
{
struct ceph_snap_realm *global_realm;
down_write(&mdsc->snap_rwsem);
global_realm = __lookup_snap_realm(mdsc, CEPH_INO_GLOBAL_SNAPREALM);
if (global_realm)
ceph_put_snap_realm(mdsc, global_realm);
__cleanup_empty_realms(mdsc);
up_write(&mdsc->snap_rwsem);
}
/*
* adjust the parent realm of a given @realm. adjust child list, and parent
* pointers, and ref counts appropriately.
*
* return true if parent was changed, 0 if unchanged, <0 on error.
*
* caller must hold snap_rwsem for write.
*/
static int adjust_snap_realm_parent(struct ceph_mds_client *mdsc,
struct ceph_snap_realm *realm,
u64 parentino)
{
struct ceph_snap_realm *parent;
lockdep_assert_held_write(&mdsc->snap_rwsem);
if (realm->parent_ino == parentino)
return 0;
parent = ceph_lookup_snap_realm(mdsc, parentino);
if (!parent) {
parent = ceph_create_snap_realm(mdsc, parentino);
if (IS_ERR(parent))
return PTR_ERR(parent);
}
dout("%s %llx %p: %llx %p -> %llx %p\n", __func__, realm->ino,
realm, realm->parent_ino, realm->parent, parentino, parent);
if (realm->parent) {
list_del_init(&realm->child_item);
ceph_put_snap_realm(mdsc, realm->parent);
}
realm->parent_ino = parentino;
realm->parent = parent;
list_add(&realm->child_item, &parent->children);
return 1;
}
static int cmpu64_rev(const void *a, const void *b)
{
if (*(u64 *)a < *(u64 *)b)
return 1;
if (*(u64 *)a > *(u64 *)b)
return -1;
return 0;
}
/*
* build the snap context for a given realm.
*/
static int build_snap_context(struct ceph_snap_realm *realm,
struct list_head *realm_queue,
struct list_head *dirty_realms)
{
struct ceph_snap_realm *parent = realm->parent;
struct ceph_snap_context *snapc;
int err = 0;
u32 num = realm->num_prior_parent_snaps + realm->num_snaps;
/*
* build parent context, if it hasn't been built.
* conservatively estimate that all parent snaps might be
* included by us.
*/
if (parent) {
if (!parent->cached_context) {
/* add to the queue head */
list_add(&parent->rebuild_item, realm_queue);
return 1;
}
num += parent->cached_context->num_snaps;
}
/* do i actually need to update? not if my context seq
matches realm seq, and my parents' does to. (this works
because we rebuild_snap_realms() works _downward_ in
hierarchy after each update.) */
if (realm->cached_context &&
realm->cached_context->seq == realm->seq &&
(!parent ||
realm->cached_context->seq >= parent->cached_context->seq)) {
dout("%s %llx %p: %p seq %lld (%u snaps) (unchanged)\n",
__func__, realm->ino, realm, realm->cached_context,
realm->cached_context->seq,
(unsigned int)realm->cached_context->num_snaps);
return 0;
}
/* alloc new snap context */
err = -ENOMEM;
if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
goto fail;
snapc = ceph_create_snap_context(num, GFP_NOFS);
if (!snapc)
goto fail;
/* build (reverse sorted) snap vector */
num = 0;
snapc->seq = realm->seq;
if (parent) {
u32 i;
/* include any of parent's snaps occurring _after_ my
parent became my parent */
for (i = 0; i < parent->cached_context->num_snaps; i++)
if (parent->cached_context->snaps[i] >=
realm->parent_since)
snapc->snaps[num++] =
parent->cached_context->snaps[i];
if (parent->cached_context->seq > snapc->seq)
snapc->seq = parent->cached_context->seq;
}
memcpy(snapc->snaps + num, realm->snaps,
sizeof(u64)*realm->num_snaps);
num += realm->num_snaps;
memcpy(snapc->snaps + num, realm->prior_parent_snaps,
sizeof(u64)*realm->num_prior_parent_snaps);
num += realm->num_prior_parent_snaps;
sort(snapc->snaps, num, sizeof(u64), cmpu64_rev, NULL);
snapc->num_snaps = num;
dout("%s %llx %p: %p seq %lld (%u snaps)\n", __func__, realm->ino,
realm, snapc, snapc->seq, (unsigned int) snapc->num_snaps);
ceph_put_snap_context(realm->cached_context);
realm->cached_context = snapc;
/* queue realm for cap_snap creation */
list_add_tail(&realm->dirty_item, dirty_realms);
return 0;
fail:
/*
* if we fail, clear old (incorrect) cached_context... hopefully
* we'll have better luck building it later
*/
if (realm->cached_context) {
ceph_put_snap_context(realm->cached_context);
realm->cached_context = NULL;
}
pr_err("%s %llx %p fail %d\n", __func__, realm->ino, realm, err);
return err;
}
/*
* rebuild snap context for the given realm and all of its children.
*/
static void rebuild_snap_realms(struct ceph_snap_realm *realm,
struct list_head *dirty_realms)
{
LIST_HEAD(realm_queue);
int last = 0;
bool skip = false;
list_add_tail(&realm->rebuild_item, &realm_queue);
while (!list_empty(&realm_queue)) {
struct ceph_snap_realm *_realm, *child;
_realm = list_first_entry(&realm_queue,
struct ceph_snap_realm,
rebuild_item);
/*
* If the last building failed dues to memory
* issue, just empty the realm_queue and return
* to avoid infinite loop.
*/
if (last < 0) {
list_del_init(&_realm->rebuild_item);
continue;
}
last = build_snap_context(_realm, &realm_queue, dirty_realms);
dout("%s %llx %p, %s\n", __func__, _realm->ino, _realm,
last > 0 ? "is deferred" : !last ? "succeeded" : "failed");
/* is any child in the list ? */
list_for_each_entry(child, &_realm->children, child_item) {
if (!list_empty(&child->rebuild_item)) {
skip = true;
break;
}
}
if (!skip) {
list_for_each_entry(child, &_realm->children, child_item)
list_add_tail(&child->rebuild_item, &realm_queue);
}
/* last == 1 means need to build parent first */
if (last <= 0)
list_del_init(&_realm->rebuild_item);
}
}
/*
* helper to allocate and decode an array of snapids. free prior
* instance, if any.
*/
static int dup_array(u64 **dst, __le64 *src, u32 num)
{
u32 i;
kfree(*dst);
if (num) {
*dst = kcalloc(num, sizeof(u64), GFP_NOFS);
if (!*dst)
return -ENOMEM;
for (i = 0; i < num; i++)
(*dst)[i] = get_unaligned_le64(src + i);
} else {
*dst = NULL;
}
return 0;
}
static bool has_new_snaps(struct ceph_snap_context *o,
struct ceph_snap_context *n)
{
if (n->num_snaps == 0)
return false;
/* snaps are in descending order */
return n->snaps[0] > o->seq;
}
/*
* When a snapshot is applied, the size/mtime inode metadata is queued
* in a ceph_cap_snap (one for each snapshot) until writeback
* completes and the metadata can be flushed back to the MDS.
*
* However, if a (sync) write is currently in-progress when we apply
* the snapshot, we have to wait until the write succeeds or fails
* (and a final size/mtime is known). In this case the
* cap_snap->writing = 1, and is said to be "pending." When the write
* finishes, we __ceph_finish_cap_snap().
*
* Caller must hold snap_rwsem for read (i.e., the realm topology won't
* change).
*/
static void ceph_queue_cap_snap(struct ceph_inode_info *ci,
struct ceph_cap_snap **pcapsnap)
{
struct inode *inode = &ci->netfs.inode;
struct ceph_snap_context *old_snapc, *new_snapc;
struct ceph_cap_snap *capsnap = *pcapsnap;
struct ceph_buffer *old_blob = NULL;
int used, dirty;
spin_lock(&ci->i_ceph_lock);
used = __ceph_caps_used(ci);
dirty = __ceph_caps_dirty(ci);
old_snapc = ci->i_head_snapc;
new_snapc = ci->i_snap_realm->cached_context;
/*
* If there is a write in progress, treat that as a dirty Fw,
* even though it hasn't completed yet; by the time we finish
* up this capsnap it will be.
*/
if (used & CEPH_CAP_FILE_WR)
dirty |= CEPH_CAP_FILE_WR;
if (__ceph_have_pending_cap_snap(ci)) {
/* there is no point in queuing multiple "pending" cap_snaps,
as no new writes are allowed to start when pending, so any
writes in progress now were started before the previous
cap_snap. lucky us. */
dout("%s %p %llx.%llx already pending\n",
__func__, inode, ceph_vinop(inode));
goto update_snapc;
}
if (ci->i_wrbuffer_ref_head == 0 &&
!(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) {
dout("%s %p %llx.%llx nothing dirty|writing\n",
__func__, inode, ceph_vinop(inode));
goto update_snapc;
}
BUG_ON(!old_snapc);
/*
* There is no need to send FLUSHSNAP message to MDS if there is
* no new snapshot. But when there is dirty pages or on-going
* writes, we still need to create cap_snap. cap_snap is needed
* by the write path and page writeback path.
*
* also see ceph_try_drop_cap_snap()
*/
if (has_new_snaps(old_snapc, new_snapc)) {
if (dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))
capsnap->need_flush = true;
} else {
if (!(used & CEPH_CAP_FILE_WR) &&
ci->i_wrbuffer_ref_head == 0) {
dout("%s %p %llx.%llx no new_snap|dirty_page|writing\n",
__func__, inode, ceph_vinop(inode));
goto update_snapc;
}
}
dout("%s %p %llx.%llx cap_snap %p queuing under %p %s %s\n",
__func__, inode, ceph_vinop(inode), capsnap, old_snapc,
ceph_cap_string(dirty), capsnap->need_flush ? "" : "no_flush");
ihold(inode);
capsnap->follows = old_snapc->seq;
capsnap->issued = __ceph_caps_issued(ci, NULL);
capsnap->dirty = dirty;
capsnap->mode = inode->i_mode;
capsnap->uid = inode->i_uid;
capsnap->gid = inode->i_gid;
if (dirty & CEPH_CAP_XATTR_EXCL) {
old_blob = __ceph_build_xattrs_blob(ci);
capsnap->xattr_blob =
ceph_buffer_get(ci->i_xattrs.blob);
capsnap->xattr_version = ci->i_xattrs.version;
} else {
capsnap->xattr_blob = NULL;
capsnap->xattr_version = 0;
}
capsnap->inline_data = ci->i_inline_version != CEPH_INLINE_NONE;
/* dirty page count moved from _head to this cap_snap;
all subsequent writes page dirties occur _after_ this
snapshot. */
capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
ci->i_wrbuffer_ref_head = 0;
capsnap->context = old_snapc;
list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
if (used & CEPH_CAP_FILE_WR) {
dout("%s %p %llx.%llx cap_snap %p snapc %p seq %llu used WR,"
" now pending\n", __func__, inode, ceph_vinop(inode),
capsnap, old_snapc, old_snapc->seq);
capsnap->writing = 1;
} else {
/* note mtime, size NOW. */
__ceph_finish_cap_snap(ci, capsnap);
}
*pcapsnap = NULL;
old_snapc = NULL;
update_snapc:
if (ci->i_wrbuffer_ref_head == 0 &&
ci->i_wr_ref == 0 &&
ci->i_dirty_caps == 0 &&
ci->i_flushing_caps == 0) {
ci->i_head_snapc = NULL;
} else {
ci->i_head_snapc = ceph_get_snap_context(new_snapc);
dout(" new snapc is %p\n", new_snapc);
}
spin_unlock(&ci->i_ceph_lock);
ceph_buffer_put(old_blob);
ceph_put_snap_context(old_snapc);
}
/*
* Finalize the size, mtime for a cap_snap.. that is, settle on final values
* to be used for the snapshot, to be flushed back to the mds.
*
* If capsnap can now be flushed, add to snap_flush list, and return 1.
*
* Caller must hold i_ceph_lock.
*/
int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
struct ceph_cap_snap *capsnap)
{
struct inode *inode = &ci->netfs.inode;
struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
BUG_ON(capsnap->writing);
capsnap->size = i_size_read(inode);
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;
if (capsnap->dirty_pages) {
dout("%s %p %llx.%llx cap_snap %p snapc %p %llu %s s=%llu "
"still has %d dirty pages\n", __func__, inode,
ceph_vinop(inode), capsnap, capsnap->context,
capsnap->context->seq, ceph_cap_string(capsnap->dirty),
capsnap->size, capsnap->dirty_pages);
return 0;
}
/* Fb cap still in use, delay it */
if (ci->i_wb_ref) {
dout("%s %p %llx.%llx cap_snap %p snapc %p %llu %s s=%llu "
"used WRBUFFER, delaying\n", __func__, inode,
ceph_vinop(inode), capsnap, capsnap->context,
capsnap->context->seq, ceph_cap_string(capsnap->dirty),
capsnap->size);
capsnap->writing = 1;
return 0;
}
ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
dout("%s %p %llx.%llx cap_snap %p snapc %p %llu %s s=%llu\n",
__func__, inode, ceph_vinop(inode), capsnap, capsnap->context,
capsnap->context->seq, ceph_cap_string(capsnap->dirty),
capsnap->size);
spin_lock(&mdsc->snap_flush_lock);
if (list_empty(&ci->i_snap_flush_item))
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 */
}
/*
* Queue cap_snaps for snap writeback for this realm and its children.
* Called under snap_rwsem, so realm topology won't change.
*/
static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
{
struct ceph_inode_info *ci;
struct inode *lastinode = NULL;
struct ceph_cap_snap *capsnap = NULL;
dout("%s %p %llx inode\n", __func__, realm, realm->ino);
spin_lock(&realm->inodes_with_caps_lock);
list_for_each_entry(ci, &realm->inodes_with_caps, i_snap_realm_item) {
struct inode *inode = igrab(&ci->netfs.inode);
if (!inode)
continue;
spin_unlock(&realm->inodes_with_caps_lock);
iput(lastinode);
lastinode = inode;
/*
* Allocate the capsnap memory outside of ceph_queue_cap_snap()
* to reduce very possible but unnecessary frequently memory
* allocate/free in this loop.
*/
if (!capsnap) {
capsnap = kmem_cache_zalloc(ceph_cap_snap_cachep, GFP_NOFS);
if (!capsnap) {
pr_err("ENOMEM allocating ceph_cap_snap on %p\n",
inode);
return;
}
}
capsnap->cap_flush.is_capsnap = true;
refcount_set(&capsnap->nref, 1);
INIT_LIST_HEAD(&capsnap->cap_flush.i_list);
INIT_LIST_HEAD(&capsnap->cap_flush.g_list);
INIT_LIST_HEAD(&capsnap->ci_item);
ceph_queue_cap_snap(ci, &capsnap);
spin_lock(&realm->inodes_with_caps_lock);
}
spin_unlock(&realm->inodes_with_caps_lock);
iput(lastinode);
if (capsnap)
kmem_cache_free(ceph_cap_snap_cachep, capsnap);
dout("%s %p %llx done\n", __func__, realm, realm->ino);
}
/*
* Parse and apply a snapblob "snap trace" from the MDS. This specifies
* the snap realm parameters from a given realm and all of its ancestors,
* up to the root.
*
* Caller must hold snap_rwsem for write.
*/
int ceph_update_snap_trace(struct ceph_mds_client *mdsc,
void *p, void *e, bool deletion,
struct ceph_snap_realm **realm_ret)
{
struct ceph_mds_snap_realm *ri; /* encoded */
__le64 *snaps; /* encoded */
__le64 *prior_parent_snaps; /* encoded */
struct ceph_snap_realm *realm;
struct ceph_snap_realm *first_realm = NULL;
struct ceph_snap_realm *realm_to_rebuild = NULL;
struct ceph_client *client = mdsc->fsc->client;
int rebuild_snapcs;
int err = -ENOMEM;
int ret;
LIST_HEAD(dirty_realms);
lockdep_assert_held_write(&mdsc->snap_rwsem);
dout("%s deletion=%d\n", __func__, deletion);
more:
realm = NULL;
rebuild_snapcs = 0;
ceph_decode_need(&p, e, sizeof(*ri), bad);
ri = p;
p += sizeof(*ri);
ceph_decode_need(&p, e, sizeof(u64)*(le32_to_cpu(ri->num_snaps) +
le32_to_cpu(ri->num_prior_parent_snaps)), bad);
snaps = p;
p += sizeof(u64) * le32_to_cpu(ri->num_snaps);
prior_parent_snaps = p;
p += sizeof(u64) * le32_to_cpu(ri->num_prior_parent_snaps);
realm = ceph_lookup_snap_realm(mdsc, le64_to_cpu(ri->ino));
if (!realm) {
realm = ceph_create_snap_realm(mdsc, le64_to_cpu(ri->ino));
if (IS_ERR(realm)) {
err = PTR_ERR(realm);
goto fail;
}
}
/* ensure the parent is correct */
err = adjust_snap_realm_parent(mdsc, realm, le64_to_cpu(ri->parent));
if (err < 0)
goto fail;
rebuild_snapcs += err;
if (le64_to_cpu(ri->seq) > realm->seq) {
dout("%s updating %llx %p %lld -> %lld\n", __func__,
realm->ino, realm, realm->seq, le64_to_cpu(ri->seq));
/* update realm parameters, snap lists */
realm->seq = le64_to_cpu(ri->seq);
realm->created = le64_to_cpu(ri->created);
realm->parent_since = le64_to_cpu(ri->parent_since);
realm->num_snaps = le32_to_cpu(ri->num_snaps);
err = dup_array(&realm->snaps, snaps, realm->num_snaps);
if (err < 0)
goto fail;
realm->num_prior_parent_snaps =
le32_to_cpu(ri->num_prior_parent_snaps);
err = dup_array(&realm->prior_parent_snaps, prior_parent_snaps,
realm->num_prior_parent_snaps);
if (err < 0)
goto fail;
if (realm->seq > mdsc->last_snap_seq)
mdsc->last_snap_seq = realm->seq;
rebuild_snapcs = 1;
} else if (!realm->cached_context) {
dout("%s %llx %p seq %lld new\n", __func__,
realm->ino, realm, realm->seq);
rebuild_snapcs = 1;
} else {
dout("%s %llx %p seq %lld unchanged\n", __func__,
realm->ino, realm, realm->seq);
}
dout("done with %llx %p, rebuild_snapcs=%d, %p %p\n", realm->ino,
realm, rebuild_snapcs, p, e);
/*
* 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;
else
ceph_put_snap_realm(mdsc, realm);
if (p < e)
goto more;
/*
* queue cap snaps _after_ we've built the new snap contexts,
* so that i_head_snapc can be set appropriately.
*/
while (!list_empty(&dirty_realms)) {
realm = list_first_entry(&dirty_realms, struct ceph_snap_realm,
dirty_item);
list_del_init(&realm->dirty_item);
queue_realm_cap_snaps(realm);
}
if (realm_ret)
*realm_ret = first_realm;
else
ceph_put_snap_realm(mdsc, first_realm);
__cleanup_empty_realms(mdsc);
return 0;
bad:
err = -EIO;
fail:
if (realm && !IS_ERR(realm))
ceph_put_snap_realm(mdsc, realm);
if (first_realm)
ceph_put_snap_realm(mdsc, first_realm);
pr_err("%s error %d\n", __func__, err);
/*
* When receiving a corrupted snap trace we don't know what
* exactly has happened in MDS side. And we shouldn't continue
* writing to OSD, which may corrupt the snapshot contents.
*
* Just try to blocklist this kclient and then this kclient
* must be remounted to continue after the corrupted metadata
* fixed in the MDS side.
*/
WRITE_ONCE(mdsc->fsc->mount_state, CEPH_MOUNT_FENCE_IO);
ret = ceph_monc_blocklist_add(&client->monc, &client->msgr.inst.addr);
if (ret)
pr_err("%s failed to blocklist %s: %d\n", __func__,
ceph_pr_addr(&client->msgr.inst.addr), ret);
WARN(1, "%s: %s%sdo remount to continue%s",
__func__, ret ? "" : ceph_pr_addr(&client->msgr.inst.addr),
ret ? "" : " was blocklisted, ",
err == -EIO ? " after corrupted snaptrace is fixed" : "");
return err;
}
/*
* Send any cap_snaps that are queued for flush. Try to carry
* s_mutex across multiple snap flushes to avoid locking overhead.
*
* Caller holds no locks.
*/
static void flush_snaps(struct ceph_mds_client *mdsc)
{
struct ceph_inode_info *ci;
struct inode *inode;
struct ceph_mds_session *session = NULL;
dout("%s\n", __func__);
spin_lock(&mdsc->snap_flush_lock);
while (!list_empty(&mdsc->snap_flush_list)) {
ci = list_first_entry(&mdsc->snap_flush_list,
struct ceph_inode_info, i_snap_flush_item);
inode = &ci->netfs.inode;
ihold(inode);
spin_unlock(&mdsc->snap_flush_lock);
ceph_flush_snaps(ci, &session);
iput(inode);
spin_lock(&mdsc->snap_flush_lock);
}
spin_unlock(&mdsc->snap_flush_lock);
ceph_put_mds_session(session);
dout("%s done\n", __func__);
}
/**
* 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.
*
* This can take two basic forms: the simplest is just a snap creation
* or deletion notification on an existing realm. This should update the
* realm and its children.
*
* The more difficult case is realm creation, due to snap creation at a
* new point in the file hierarchy, or due to a rename that moves a file or
* directory into another realm.
*/
void ceph_handle_snap(struct ceph_mds_client *mdsc,
struct ceph_mds_session *session,
struct ceph_msg *msg)
{
struct super_block *sb = mdsc->fsc->sb;
int mds = session->s_mds;
u64 split;
int op;
int trace_len;
struct ceph_snap_realm *realm = NULL;
void *p = msg->front.iov_base;
void *e = p + msg->front.iov_len;
struct ceph_mds_snap_head *h;
int num_split_inos, num_split_realms;
__le64 *split_inos = NULL, *split_realms = NULL;
int i;
int locked_rwsem = 0;
bool close_sessions = false;
/* decode */
if (msg->front.iov_len < sizeof(*h))
goto bad;
h = p;
op = le32_to_cpu(h->op);
split = le64_to_cpu(h->split); /* non-zero if we are splitting an
* existing realm */
num_split_inos = le32_to_cpu(h->num_split_inos);
num_split_realms = le32_to_cpu(h->num_split_realms);
trace_len = le32_to_cpu(h->trace_len);
p += sizeof(*h);
dout("%s from mds%d op %s split %llx tracelen %d\n", __func__,
mds, ceph_snap_op_name(op), split, trace_len);
mutex_lock(&session->s_mutex);
inc_session_sequence(session);
mutex_unlock(&session->s_mutex);
down_write(&mdsc->snap_rwsem);
locked_rwsem = 1;
if (op == CEPH_SNAP_OP_SPLIT) {
struct ceph_mds_snap_realm *ri;
/*
* A "split" breaks part of an existing realm off into
* a new realm. The MDS provides a list of inodes
* (with caps) and child realms that belong to the new
* child.
*/
split_inos = p;
p += sizeof(u64) * num_split_inos;
split_realms = p;
p += sizeof(u64) * num_split_realms;
ceph_decode_need(&p, e, sizeof(*ri), bad);
/* we will peek at realm info here, but will _not_
* advance p, as the realm update will occur below in
* ceph_update_snap_trace. */
ri = p;
realm = ceph_lookup_snap_realm(mdsc, split);
if (!realm) {
realm = ceph_create_snap_realm(mdsc, split);
if (IS_ERR(realm))
goto out;
}
dout("splitting snap_realm %llx %p\n", realm->ino, realm);
for (i = 0; i < num_split_inos; i++) {
struct ceph_vino vino = {
.ino = le64_to_cpu(split_inos[i]),
.snap = CEPH_NOSNAP,
};
struct inode *inode = ceph_find_inode(sb, vino);
struct ceph_inode_info *ci;
if (!inode)
continue;
ci = ceph_inode(inode);
spin_lock(&ci->i_ceph_lock);
if (!ci->i_snap_realm)
goto skip_inode;
/*
* If this inode belongs to a realm that was
* created after our new realm, we experienced
* a race (due to another split notifications
* arriving from a different MDS). So skip
* this inode.
*/
if (ci->i_snap_realm->created >
le64_to_cpu(ri->created)) {
dout(" leaving %p %llx.%llx in newer realm %llx %p\n",
inode, ceph_vinop(inode), ci->i_snap_realm->ino,
ci->i_snap_realm);
goto skip_inode;
}
dout(" will move %p %llx.%llx to split realm %llx %p\n",
inode, ceph_vinop(inode), realm->ino, realm);
ceph_get_snap_realm(mdsc, realm);
ceph_change_snap_realm(inode, realm);
spin_unlock(&ci->i_ceph_lock);
iput(inode);
continue;
skip_inode:
spin_unlock(&ci->i_ceph_lock);
iput(inode);
}
/* we may have taken some of the old realm's children. */
for (i = 0; i < num_split_realms; i++) {
struct ceph_snap_realm *child =
__lookup_snap_realm(mdsc,
le64_to_cpu(split_realms[i]));
if (!child)
continue;
adjust_snap_realm_parent(mdsc, child, realm->ino);
}
}
/*
* update using the provided snap trace. if we are deleting a
* snap, we can avoid queueing cap_snaps.
*/
if (ceph_update_snap_trace(mdsc, p, e,
op == CEPH_SNAP_OP_DESTROY,
NULL)) {
close_sessions = true;
goto bad;
}
if (op == CEPH_SNAP_OP_SPLIT)
/* we took a reference when we created the realm, above */
ceph_put_snap_realm(mdsc, realm);
__cleanup_empty_realms(mdsc);
up_write(&mdsc->snap_rwsem);
flush_snaps(mdsc);
return;
bad:
pr_err("%s corrupt snap message from mds%d\n", __func__, mds);
ceph_msg_dump(msg);
out:
if (locked_rwsem)
up_write(&mdsc->snap_rwsem);
if (close_sessions)
ceph_mdsc_close_sessions(mdsc);
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("%s found snapid map %llx -> %x\n", __func__,
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("%s found snapid map %llx -> %x\n", __func__,
exist->snap, exist->dev);
return exist;
}
dout("%s create snapid map %llx -> %x\n", __func__,
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);
}
}