Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
#include <linux/ceph/ceph_debug.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);
 
<------>atomic_set(&realm->nref, 1);    /* for caller */
<------>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->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;
}
 
/*
 * 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("lookup_snap_realm %llx %p\n", 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("__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);
<------><------>__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_empty_realms(struct ceph_mds_client *mdsc)
{
<------>down_write(&mdsc->snap_rwsem);
<------>__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("adjust_snap_realm_parent %llx %p: %llx %p -> %llx %p\n",
<------>     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* 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) {
<------><------><------>err = build_snap_context(parent, dirty_realms);
<------><------><------>if (err)
<------><------><------><------>goto fail;
<------><------>}
<------><------>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("build_snap_context %llx %p: %p seq %lld (%u snaps)"
<------><------>     " (unchanged)\n",
<------><------>     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("build_snap_context %llx %p: %p seq %lld (%u snaps)\n",
<------>     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("build_snap_context %llx %p fail %d\n", 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)
{
<------>struct ceph_snap_realm *child;
 
<------>dout("rebuild_snap_realms %llx %p\n", realm->ino, realm);
<------>build_snap_context(realm, dirty_realms);
 
<------>list_for_each_entry(child, &realm->children, child_item)
<------><------>rebuild_snap_realms(child, dirty_realms);
}
 
 
/*
 * 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).
 */
void ceph_queue_cap_snap(struct ceph_inode_info *ci)
{
<------>struct inode *inode = &ci->vfs_inode;
<------>struct ceph_cap_snap *capsnap;
<------>struct ceph_snap_context *old_snapc, *new_snapc;
<------>struct ceph_buffer *old_blob = NULL;
<------>int used, dirty;
 
<------>capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
<------>if (!capsnap) {
<------><------>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);
<------>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("queue_cap_snap %p already pending\n", inode);
<------><------>goto update_snapc;
<------>}
<------>if (ci->i_wrbuffer_ref_head == 0 &&
<------>    !(dirty & (CEPH_CAP_ANY_EXCL|CEPH_CAP_FILE_WR))) {
<------><------>dout("queue_cap_snap %p nothing dirty|writing\n", 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("queue_cap_snap %p "
<------><------><------>     "no new_snap|dirty_page|writing\n", inode);
<------><------><------>goto update_snapc;
<------><------>}
<------>}
 
<------>dout("queue_cap_snap %p cap_snap %p queuing under %p %s %s\n",
<------>     inode, capsnap, old_snapc, ceph_cap_string(dirty),
<------>     capsnap->need_flush ? "" : "no_flush");
<------>ihold(inode);
 
<------>refcount_set(&capsnap->nref, 1);
<------>INIT_LIST_HEAD(&capsnap->ci_item);
 
<------>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("queue_cap_snap %p cap_snap %p snapc %p"
<------><------>     " seq %llu used WR, now pending\n", inode,
<------><------>     capsnap, old_snapc, old_snapc->seq);
<------><------>capsnap->writing = 1;
<------>} else {
<------><------>/* note mtime, size NOW. */
<------><------>__ceph_finish_cap_snap(ci, capsnap);
<------>}
<------>capsnap = 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);
<------>kfree(capsnap);
<------>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->vfs_inode;
<------>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;
<------>if (capsnap->dirty_pages) {
<------><------>dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu "
<------><------>     "still has %d dirty pages\n", inode, capsnap,
<------><------>     capsnap->context, capsnap->context->seq,
<------><------>     ceph_cap_string(capsnap->dirty), capsnap->size,
<------><------>     capsnap->dirty_pages);
<------><------>return 0;
<------>}
 
<------>ci->i_ceph_flags |= CEPH_I_FLUSH_SNAPS;
<------>dout("finish_cap_snap %p cap_snap %p snapc %p %llu %s s=%llu\n",
<------>     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;
 
<------>dout("queue_realm_cap_snaps %p %llx inodes\n", 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->vfs_inode);
<------><------>if (!inode)
<------><------><------>continue;
<------><------>spin_unlock(&realm->inodes_with_caps_lock);
<------><------>/* 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);
<------>ceph_async_iput(lastinode);
 
<------>dout("queue_realm_cap_snaps %p %llx done\n", 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 = NULL;
<------>struct ceph_snap_realm *first_realm = NULL;
<------>int invalidate = 0;
<------>int err = -ENOMEM;
<------>LIST_HEAD(dirty_realms);
 
<------>lockdep_assert_held_write(&mdsc->snap_rwsem);
 
<------>dout("update_snap_trace deletion=%d\n", deletion);
more:
<------>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;
<------>invalidate += err;
 
<------>if (le64_to_cpu(ri->seq) > realm->seq) {
<------><------>dout("update_snap_trace updating %llx %p %lld -> %lld\n",
<------><------>     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;
 
<------><------>invalidate = 1;
<------>} else if (!realm->cached_context) {
<------><------>dout("update_snap_trace %llx %p seq %lld new\n",
<------><------>     realm->ino, realm, realm->seq);
<------><------>invalidate = 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);
 
<------>/* invalidate when we reach the _end_ (root) of the trace */
<------>if (invalidate && p >= e)
<------><------>rebuild_snap_realms(realm, &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 = -EINVAL;
fail:
<------>if (realm && !IS_ERR(realm))
<------><------>ceph_put_snap_realm(mdsc, realm);
<------>if (first_realm)
<------><------>ceph_put_snap_realm(mdsc, first_realm);
<------>pr_err("update_snap_trace error %d\n", err);
<------>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("flush_snaps\n");
<------>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->vfs_inode;
<------><------>ihold(inode);
<------><------>spin_unlock(&mdsc->snap_flush_lock);
<------><------>ceph_flush_snaps(ci, &session);
<------><------>/* 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);
 
<------>if (session) {
<------><------>mutex_unlock(&session->s_mutex);
<------><------>ceph_put_mds_session(session);
<------>}
<------>dout("flush_snaps done\n");
}
 
 
/*
 * 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;
 
<------>/* 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("handle_snap from mds%d op %s split %llx tracelen %d\n", 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;
<------><------><------>struct ceph_snap_realm *oldrealm;
 
<------><------><------>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 in newer realm %llx %p\n",
<------><------><------><------>     inode, ci->i_snap_realm->ino,
<------><------><------><------>     ci->i_snap_realm);
<------><------><------><------>goto skip_inode;
<------><------><------>}
<------><------><------>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);
 
<------><------><------>/* 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);
<------><------><------>ceph_async_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.
<------> */
<------>ceph_update_snap_trace(mdsc, p, e,
<------><------><------>       op == CEPH_SNAP_OP_DESTROY, NULL);
 
<------>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("corrupt snap message from mds%d\n", mds);
<------>ceph_msg_dump(msg);
out:
<------>if (locked_rwsem)
<------><------>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);
<------>}
}