Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

[mirror_ubuntu-jammy-kernel.git] / fs / ceph / inode.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/ceph/ceph_debug.h>

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/writeback.h>
#include <linux/vmalloc.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/random.h>
#include <linux/sort.h>
#include <linux/iversion.h>

#include "super.h"
#include "mds_client.h"
#include "cache.h"
#include <linux/ceph/decode.h>

/*
 * Ceph inode operations
 *
 * Implement basic inode helpers (get, alloc) and inode ops (getattr,
 * setattr, etc.), xattr helpers, and helpers for assimilating
 * metadata returned by the MDS into our cache.
 *
 * Also define helpers for doing asynchronous writeback, invalidation,
 * and truncation for the benefit of those who can't afford to block
 * (typically because they are in the message handler path).
 */

static const struct inode_operations ceph_symlink_iops;

static void ceph_inode_work(struct work_struct *work);

/*
 * find or create an inode, given the ceph ino number
 */
static int ceph_set_ino_cb(struct inode *inode, void *data)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);

        ci->i_vino = *(struct ceph_vino *)data;
        inode->i_ino = ceph_vino_to_ino_t(ci->i_vino);
        inode_set_iversion_raw(inode, 0);
        percpu_counter_inc(&mdsc->metric.total_inodes);

        return 0;
}

struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino)
{
        struct inode *inode;

        if (ceph_vino_is_reserved(vino))
                return ERR_PTR(-EREMOTEIO);

        inode = iget5_locked(sb, (unsigned long)vino.ino, ceph_ino_compare,
                             ceph_set_ino_cb, &vino);
        if (!inode)
                return ERR_PTR(-ENOMEM);

        dout("get_inode on %llu=%llx.%llx got %p new %d\n", ceph_present_inode(inode),
             ceph_vinop(inode), inode, !!(inode->i_state & I_NEW));
        return inode;
}

/*
 * get/constuct snapdir inode for a given directory
 */
struct inode *ceph_get_snapdir(struct inode *parent)
{
        struct ceph_vino vino = {
                .ino = ceph_ino(parent),
                .snap = CEPH_SNAPDIR,
        };
        struct inode *inode = ceph_get_inode(parent->i_sb, vino);
        struct ceph_inode_info *ci = ceph_inode(inode);

        if (IS_ERR(inode))
                return inode;

        if (!S_ISDIR(parent->i_mode)) {
                pr_warn_once("bad snapdir parent type (mode=0%o)\n",
                             parent->i_mode);
                return ERR_PTR(-ENOTDIR);
        }

        if (!(inode->i_state & I_NEW) && !S_ISDIR(inode->i_mode)) {
                pr_warn_once("bad snapdir inode type (mode=0%o)\n",
                             inode->i_mode);
                return ERR_PTR(-ENOTDIR);
        }

        inode->i_mode = parent->i_mode;
        inode->i_uid = parent->i_uid;
        inode->i_gid = parent->i_gid;
        inode->i_mtime = parent->i_mtime;
        inode->i_ctime = parent->i_ctime;
        inode->i_atime = parent->i_atime;
        ci->i_rbytes = 0;
        ci->i_btime = ceph_inode(parent)->i_btime;

        if (inode->i_state & I_NEW) {
                inode->i_op = &ceph_snapdir_iops;
                inode->i_fop = &ceph_snapdir_fops;
                ci->i_snap_caps = CEPH_CAP_PIN; /* so we can open */
                unlock_new_inode(inode);
        }

        return inode;
}

const struct inode_operations ceph_file_iops = {
        .permission = ceph_permission,
        .setattr = ceph_setattr,
        .getattr = ceph_getattr,
        .listxattr = ceph_listxattr,
        .get_acl = ceph_get_acl,
        .set_acl = ceph_set_acl,
};


/*
 * We use a 'frag tree' to keep track of the MDS's directory fragments
 * for a given inode (usually there is just a single fragment).  We
 * need to know when a child frag is delegated to a new MDS, or when
 * it is flagged as replicated, so we can direct our requests
 * accordingly.
 */

/*
 * find/create a frag in the tree
 */
static struct ceph_inode_frag *__get_or_create_frag(struct ceph_inode_info *ci,
                                                    u32 f)
{
        struct rb_node **p;
        struct rb_node *parent = NULL;
        struct ceph_inode_frag *frag;
        int c;

        p = &ci->i_fragtree.rb_node;
        while (*p) {
                parent = *p;
                frag = rb_entry(parent, struct ceph_inode_frag, node);
                c = ceph_frag_compare(f, frag->frag);
                if (c < 0)
                        p = &(*p)->rb_left;
                else if (c > 0)
                        p = &(*p)->rb_right;
                else
                        return frag;
        }

        frag = kmalloc(sizeof(*frag), GFP_NOFS);
        if (!frag)
                return ERR_PTR(-ENOMEM);

        frag->frag = f;
        frag->split_by = 0;
        frag->mds = -1;
        frag->ndist = 0;

        rb_link_node(&frag->node, parent, p);
        rb_insert_color(&frag->node, &ci->i_fragtree);

        dout("get_or_create_frag added %llx.%llx frag %x\n",
             ceph_vinop(&ci->vfs_inode), f);
        return frag;
}

/*
 * find a specific frag @f
 */
struct ceph_inode_frag *__ceph_find_frag(struct ceph_inode_info *ci, u32 f)
{
        struct rb_node *n = ci->i_fragtree.rb_node;

        while (n) {
                struct ceph_inode_frag *frag =
                        rb_entry(n, struct ceph_inode_frag, node);
                int c = ceph_frag_compare(f, frag->frag);
                if (c < 0)
                        n = n->rb_left;
                else if (c > 0)
                        n = n->rb_right;
                else
                        return frag;
        }
        return NULL;
}

/*
 * Choose frag containing the given value @v.  If @pfrag is
 * specified, copy the frag delegation info to the caller if
 * it is present.
 */
static u32 __ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
                              struct ceph_inode_frag *pfrag, int *found)
{
        u32 t = ceph_frag_make(0, 0);
        struct ceph_inode_frag *frag;
        unsigned nway, i;
        u32 n;

        if (found)
                *found = 0;

        while (1) {
                WARN_ON(!ceph_frag_contains_value(t, v));
                frag = __ceph_find_frag(ci, t);
                if (!frag)
                        break; /* t is a leaf */
                if (frag->split_by == 0) {
                        if (pfrag)
                                memcpy(pfrag, frag, sizeof(*pfrag));
                        if (found)
                                *found = 1;
                        break;
                }

                /* choose child */
                nway = 1 << frag->split_by;
                dout("choose_frag(%x) %x splits by %d (%d ways)\n", v, t,
                     frag->split_by, nway);
                for (i = 0; i < nway; i++) {
                        n = ceph_frag_make_child(t, frag->split_by, i);
                        if (ceph_frag_contains_value(n, v)) {
                                t = n;
                                break;
                        }
                }
                BUG_ON(i == nway);
        }
        dout("choose_frag(%x) = %x\n", v, t);

        return t;
}

u32 ceph_choose_frag(struct ceph_inode_info *ci, u32 v,
                     struct ceph_inode_frag *pfrag, int *found)
{
        u32 ret;
        mutex_lock(&ci->i_fragtree_mutex);
        ret = __ceph_choose_frag(ci, v, pfrag, found);
        mutex_unlock(&ci->i_fragtree_mutex);
        return ret;
}

/*
 * Process dirfrag (delegation) info from the mds.  Include leaf
 * fragment in tree ONLY if ndist > 0.  Otherwise, only
 * branches/splits are included in i_fragtree)
 */
static int ceph_fill_dirfrag(struct inode *inode,
                             struct ceph_mds_reply_dirfrag *dirinfo)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        struct ceph_inode_frag *frag;
        u32 id = le32_to_cpu(dirinfo->frag);
        int mds = le32_to_cpu(dirinfo->auth);
        int ndist = le32_to_cpu(dirinfo->ndist);
        int diri_auth = -1;
        int i;
        int err = 0;

        spin_lock(&ci->i_ceph_lock);
        if (ci->i_auth_cap)
                diri_auth = ci->i_auth_cap->mds;
        spin_unlock(&ci->i_ceph_lock);

        if (mds == -1) /* CDIR_AUTH_PARENT */
                mds = diri_auth;

        mutex_lock(&ci->i_fragtree_mutex);
        if (ndist == 0 && mds == diri_auth) {
                /* no delegation info needed. */
                frag = __ceph_find_frag(ci, id);
                if (!frag)
                        goto out;
                if (frag->split_by == 0) {
                        /* tree leaf, remove */
                        dout("fill_dirfrag removed %llx.%llx frag %x"
                             " (no ref)\n", ceph_vinop(inode), id);
                        rb_erase(&frag->node, &ci->i_fragtree);
                        kfree(frag);
                } else {
                        /* tree branch, keep and clear */
                        dout("fill_dirfrag cleared %llx.%llx frag %x"
                             " referral\n", ceph_vinop(inode), id);
                        frag->mds = -1;
                        frag->ndist = 0;
                }
                goto out;
        }


        /* find/add this frag to store mds delegation info */
        frag = __get_or_create_frag(ci, id);
        if (IS_ERR(frag)) {
                /* this is not the end of the world; we can continue
                   with bad/inaccurate delegation info */
                pr_err("fill_dirfrag ENOMEM on mds ref %llx.%llx fg %x\n",
                       ceph_vinop(inode), le32_to_cpu(dirinfo->frag));
                err = -ENOMEM;
                goto out;
        }

        frag->mds = mds;
        frag->ndist = min_t(u32, ndist, CEPH_MAX_DIRFRAG_REP);
        for (i = 0; i < frag->ndist; i++)
                frag->dist[i] = le32_to_cpu(dirinfo->dist[i]);
        dout("fill_dirfrag %llx.%llx frag %x ndist=%d\n",
             ceph_vinop(inode), frag->frag, frag->ndist);

out:
        mutex_unlock(&ci->i_fragtree_mutex);
        return err;
}

static int frag_tree_split_cmp(const void *l, const void *r)
{
        struct ceph_frag_tree_split *ls = (struct ceph_frag_tree_split*)l;
        struct ceph_frag_tree_split *rs = (struct ceph_frag_tree_split*)r;
        return ceph_frag_compare(le32_to_cpu(ls->frag),
                                 le32_to_cpu(rs->frag));
}

static bool is_frag_child(u32 f, struct ceph_inode_frag *frag)
{
        if (!frag)
                return f == ceph_frag_make(0, 0);
        if (ceph_frag_bits(f) != ceph_frag_bits(frag->frag) + frag->split_by)
                return false;
        return ceph_frag_contains_value(frag->frag, ceph_frag_value(f));
}

static int ceph_fill_fragtree(struct inode *inode,
                              struct ceph_frag_tree_head *fragtree,
                              struct ceph_mds_reply_dirfrag *dirinfo)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        struct ceph_inode_frag *frag, *prev_frag = NULL;
        struct rb_node *rb_node;
        unsigned i, split_by, nsplits;
        u32 id;
        bool update = false;

        mutex_lock(&ci->i_fragtree_mutex);
        nsplits = le32_to_cpu(fragtree->nsplits);
        if (nsplits != ci->i_fragtree_nsplits) {
                update = true;
        } else if (nsplits) {
                i = prandom_u32() % nsplits;
                id = le32_to_cpu(fragtree->splits[i].frag);
                if (!__ceph_find_frag(ci, id))
                        update = true;
        } else if (!RB_EMPTY_ROOT(&ci->i_fragtree)) {
                rb_node = rb_first(&ci->i_fragtree);
                frag = rb_entry(rb_node, struct ceph_inode_frag, node);
                if (frag->frag != ceph_frag_make(0, 0) || rb_next(rb_node))
                        update = true;
        }
        if (!update && dirinfo) {
                id = le32_to_cpu(dirinfo->frag);
                if (id != __ceph_choose_frag(ci, id, NULL, NULL))
                        update = true;
        }
        if (!update)
                goto out_unlock;

        if (nsplits > 1) {
                sort(fragtree->splits, nsplits, sizeof(fragtree->splits[0]),
                     frag_tree_split_cmp, NULL);
        }

        dout("fill_fragtree %llx.%llx\n", ceph_vinop(inode));
        rb_node = rb_first(&ci->i_fragtree);
        for (i = 0; i < nsplits; i++) {
                id = le32_to_cpu(fragtree->splits[i].frag);
                split_by = le32_to_cpu(fragtree->splits[i].by);
                if (split_by == 0 || ceph_frag_bits(id) + split_by > 24) {
                        pr_err("fill_fragtree %llx.%llx invalid split %d/%u, "
                               "frag %x split by %d\n", ceph_vinop(inode),
                               i, nsplits, id, split_by);
                        continue;
                }
                frag = NULL;
                while (rb_node) {
                        frag = rb_entry(rb_node, struct ceph_inode_frag, node);
                        if (ceph_frag_compare(frag->frag, id) >= 0) {
                                if (frag->frag != id)
                                        frag = NULL;
                                else
                                        rb_node = rb_next(rb_node);
                                break;
                        }
                        rb_node = rb_next(rb_node);
                        /* delete stale split/leaf node */
                        if (frag->split_by > 0 ||
                            !is_frag_child(frag->frag, prev_frag)) {
                                rb_erase(&frag->node, &ci->i_fragtree);
                                if (frag->split_by > 0)
                                        ci->i_fragtree_nsplits--;
                                kfree(frag);
                        }
                        frag = NULL;
                }
                if (!frag) {
                        frag = __get_or_create_frag(ci, id);
                        if (IS_ERR(frag))
                                continue;
                }
                if (frag->split_by == 0)
                        ci->i_fragtree_nsplits++;
                frag->split_by = split_by;
                dout(" frag %x split by %d\n", frag->frag, frag->split_by);
                prev_frag = frag;
        }
        while (rb_node) {
                frag = rb_entry(rb_node, struct ceph_inode_frag, node);
                rb_node = rb_next(rb_node);
                /* delete stale split/leaf node */
                if (frag->split_by > 0 ||
                    !is_frag_child(frag->frag, prev_frag)) {
                        rb_erase(&frag->node, &ci->i_fragtree);
                        if (frag->split_by > 0)
                                ci->i_fragtree_nsplits--;
                        kfree(frag);
                }
        }
out_unlock:
        mutex_unlock(&ci->i_fragtree_mutex);
        return 0;
}

/*
 * initialize a newly allocated inode.
 */
struct inode *ceph_alloc_inode(struct super_block *sb)
{
        struct ceph_inode_info *ci;
        int i;

        ci = kmem_cache_alloc(ceph_inode_cachep, GFP_NOFS);
        if (!ci)
                return NULL;

        dout("alloc_inode %p\n", &ci->vfs_inode);

        spin_lock_init(&ci->i_ceph_lock);

        ci->i_version = 0;
        ci->i_inline_version = 0;
        ci->i_time_warp_seq = 0;
        ci->i_ceph_flags = 0;
        atomic64_set(&ci->i_ordered_count, 1);
        atomic64_set(&ci->i_release_count, 1);
        atomic64_set(&ci->i_complete_seq[0], 0);
        atomic64_set(&ci->i_complete_seq[1], 0);
        ci->i_symlink = NULL;

        ci->i_max_bytes = 0;
        ci->i_max_files = 0;

        memset(&ci->i_dir_layout, 0, sizeof(ci->i_dir_layout));
        memset(&ci->i_cached_layout, 0, sizeof(ci->i_cached_layout));
        RCU_INIT_POINTER(ci->i_layout.pool_ns, NULL);

        ci->i_fragtree = RB_ROOT;
        mutex_init(&ci->i_fragtree_mutex);

        ci->i_xattrs.blob = NULL;
        ci->i_xattrs.prealloc_blob = NULL;
        ci->i_xattrs.dirty = false;
        ci->i_xattrs.index = RB_ROOT;
        ci->i_xattrs.count = 0;
        ci->i_xattrs.names_size = 0;
        ci->i_xattrs.vals_size = 0;
        ci->i_xattrs.version = 0;
        ci->i_xattrs.index_version = 0;

        ci->i_caps = RB_ROOT;
        ci->i_auth_cap = NULL;
        ci->i_dirty_caps = 0;
        ci->i_flushing_caps = 0;
        INIT_LIST_HEAD(&ci->i_dirty_item);
        INIT_LIST_HEAD(&ci->i_flushing_item);
        ci->i_prealloc_cap_flush = NULL;
        INIT_LIST_HEAD(&ci->i_cap_flush_list);
        init_waitqueue_head(&ci->i_cap_wq);
        ci->i_hold_caps_max = 0;
        INIT_LIST_HEAD(&ci->i_cap_delay_list);
        INIT_LIST_HEAD(&ci->i_cap_snaps);
        ci->i_head_snapc = NULL;
        ci->i_snap_caps = 0;

        ci->i_last_rd = ci->i_last_wr = jiffies - 3600 * HZ;
        for (i = 0; i < CEPH_FILE_MODE_BITS; i++)
                ci->i_nr_by_mode[i] = 0;

        mutex_init(&ci->i_truncate_mutex);
        ci->i_truncate_seq = 0;
        ci->i_truncate_size = 0;
        ci->i_truncate_pending = 0;

        ci->i_max_size = 0;
        ci->i_reported_size = 0;
        ci->i_wanted_max_size = 0;
        ci->i_requested_max_size = 0;

        ci->i_pin_ref = 0;
        ci->i_rd_ref = 0;
        ci->i_rdcache_ref = 0;
        ci->i_wr_ref = 0;
        ci->i_wb_ref = 0;
        ci->i_fx_ref = 0;
        ci->i_wrbuffer_ref = 0;
        ci->i_wrbuffer_ref_head = 0;
        atomic_set(&ci->i_filelock_ref, 0);
        atomic_set(&ci->i_shared_gen, 1);
        ci->i_rdcache_gen = 0;
        ci->i_rdcache_revoking = 0;

        INIT_LIST_HEAD(&ci->i_unsafe_dirops);
        INIT_LIST_HEAD(&ci->i_unsafe_iops);
        spin_lock_init(&ci->i_unsafe_lock);

        ci->i_snap_realm = NULL;
        INIT_LIST_HEAD(&ci->i_snap_realm_item);
        INIT_LIST_HEAD(&ci->i_snap_flush_item);

        INIT_WORK(&ci->i_work, ceph_inode_work);
        ci->i_work_mask = 0;
        memset(&ci->i_btime, '\0', sizeof(ci->i_btime));

        ceph_fscache_inode_init(ci);

        ci->i_meta_err = 0;

        return &ci->vfs_inode;
}

void ceph_free_inode(struct inode *inode)
{
        struct ceph_inode_info *ci = ceph_inode(inode);

        kfree(ci->i_symlink);
        kmem_cache_free(ceph_inode_cachep, ci);
}

void ceph_evict_inode(struct inode *inode)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
        struct ceph_inode_frag *frag;
        struct rb_node *n;

        dout("evict_inode %p ino %llx.%llx\n", inode, ceph_vinop(inode));

        percpu_counter_dec(&mdsc->metric.total_inodes);

        truncate_inode_pages_final(&inode->i_data);
        clear_inode(inode);

        ceph_fscache_unregister_inode_cookie(ci);

        __ceph_remove_caps(ci);

        if (__ceph_has_any_quota(ci))
                ceph_adjust_quota_realms_count(inode, false);

        /*
         * we may still have a snap_realm reference if there are stray
         * caps in i_snap_caps.
         */
        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);
                } else {
                        ceph_put_snapid_map(mdsc, ci->i_snapid_map);
                        ci->i_snap_realm = NULL;
                }
        }

        while ((n = rb_first(&ci->i_fragtree)) != NULL) {
                frag = rb_entry(n, struct ceph_inode_frag, node);
                rb_erase(n, &ci->i_fragtree);
                kfree(frag);
        }
        ci->i_fragtree_nsplits = 0;

        __ceph_destroy_xattrs(ci);
        if (ci->i_xattrs.blob)
                ceph_buffer_put(ci->i_xattrs.blob);
        if (ci->i_xattrs.prealloc_blob)
                ceph_buffer_put(ci->i_xattrs.prealloc_blob);

        ceph_put_string(rcu_dereference_raw(ci->i_layout.pool_ns));
        ceph_put_string(rcu_dereference_raw(ci->i_cached_layout.pool_ns));
}

static inline blkcnt_t calc_inode_blocks(u64 size)
{
        return (size + (1<<9) - 1) >> 9;
}

/*
 * Helpers to fill in size, ctime, mtime, and atime.  We have to be
 * careful because either the client or MDS may have more up to date
 * info, depending on which capabilities are held, and whether
 * time_warp_seq or truncate_seq have increased.  (Ordinarily, mtime
 * and size are monotonically increasing, except when utimes() or
 * truncate() increments the corresponding _seq values.)
 */
int ceph_fill_file_size(struct inode *inode, int issued,
                        u32 truncate_seq, u64 truncate_size, u64 size)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        int queue_trunc = 0;
        loff_t isize = i_size_read(inode);

        if (ceph_seq_cmp(truncate_seq, ci->i_truncate_seq) > 0 ||
            (truncate_seq == ci->i_truncate_seq && size > isize)) {
                dout("size %lld -> %llu\n", isize, size);
                if (size > 0 && S_ISDIR(inode->i_mode)) {
                        pr_err("fill_file_size non-zero size for directory\n");
                        size = 0;
                }
                i_size_write(inode, size);
                inode->i_blocks = calc_inode_blocks(size);
                ci->i_reported_size = size;
                if (truncate_seq != ci->i_truncate_seq) {
                        dout("truncate_seq %u -> %u\n",
                             ci->i_truncate_seq, truncate_seq);
                        ci->i_truncate_seq = truncate_seq;

                        /* the MDS should have revoked these caps */
                        WARN_ON_ONCE(issued & (CEPH_CAP_FILE_EXCL |
                                               CEPH_CAP_FILE_RD |
                                               CEPH_CAP_FILE_WR |
                                               CEPH_CAP_FILE_LAZYIO));
                        /*
                         * If we hold relevant caps, or in the case where we're
                         * not the only client referencing this file and we
                         * don't hold those caps, then we need to check whether
                         * the file is either opened or mmaped
                         */
                        if ((issued & (CEPH_CAP_FILE_CACHE|
                                       CEPH_CAP_FILE_BUFFER)) ||
                            mapping_mapped(inode->i_mapping) ||
                            __ceph_is_file_opened(ci)) {
                                ci->i_truncate_pending++;
                                queue_trunc = 1;
                        }
                }
        }
        if (ceph_seq_cmp(truncate_seq, ci->i_truncate_seq) >= 0 &&
            ci->i_truncate_size != truncate_size) {
                dout("truncate_size %lld -> %llu\n", ci->i_truncate_size,
                     truncate_size);
                ci->i_truncate_size = truncate_size;
        }

        if (queue_trunc)
                ceph_fscache_invalidate(inode);

        return queue_trunc;
}

void ceph_fill_file_time(struct inode *inode, int issued,
                         u64 time_warp_seq, struct timespec64 *ctime,
                         struct timespec64 *mtime, struct timespec64 *atime)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        int warn = 0;

        if (issued & (CEPH_CAP_FILE_EXCL|
                      CEPH_CAP_FILE_WR|
                      CEPH_CAP_FILE_BUFFER|
                      CEPH_CAP_AUTH_EXCL|
                      CEPH_CAP_XATTR_EXCL)) {
                if (ci->i_version == 0 ||
                    timespec64_compare(ctime, &inode->i_ctime) > 0) {
                        dout("ctime %lld.%09ld -> %lld.%09ld inc w/ cap\n",
                             inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
                             ctime->tv_sec, ctime->tv_nsec);
                        inode->i_ctime = *ctime;
                }
                if (ci->i_version == 0 ||
                    ceph_seq_cmp(time_warp_seq, ci->i_time_warp_seq) > 0) {
                        /* the MDS did a utimes() */
                        dout("mtime %lld.%09ld -> %lld.%09ld "
                             "tw %d -> %d\n",
                             inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
                             mtime->tv_sec, mtime->tv_nsec,
                             ci->i_time_warp_seq, (int)time_warp_seq);

                        inode->i_mtime = *mtime;
                        inode->i_atime = *atime;
                        ci->i_time_warp_seq = time_warp_seq;
                } else if (time_warp_seq == ci->i_time_warp_seq) {
                        /* nobody did utimes(); take the max */
                        if (timespec64_compare(mtime, &inode->i_mtime) > 0) {
                                dout("mtime %lld.%09ld -> %lld.%09ld inc\n",
                                     inode->i_mtime.tv_sec,
                                     inode->i_mtime.tv_nsec,
                                     mtime->tv_sec, mtime->tv_nsec);
                                inode->i_mtime = *mtime;
                        }
                        if (timespec64_compare(atime, &inode->i_atime) > 0) {
                                dout("atime %lld.%09ld -> %lld.%09ld inc\n",
                                     inode->i_atime.tv_sec,
                                     inode->i_atime.tv_nsec,
                                     atime->tv_sec, atime->tv_nsec);
                                inode->i_atime = *atime;
                        }
                } else if (issued & CEPH_CAP_FILE_EXCL) {
                        /* we did a utimes(); ignore mds values */
                } else {
                        warn = 1;
                }
        } else {
                /* we have no write|excl caps; whatever the MDS says is true */
                if (ceph_seq_cmp(time_warp_seq, ci->i_time_warp_seq) >= 0) {
                        inode->i_ctime = *ctime;
                        inode->i_mtime = *mtime;
                        inode->i_atime = *atime;
                        ci->i_time_warp_seq = time_warp_seq;
                } else {
                        warn = 1;
                }
        }
        if (warn) /* time_warp_seq shouldn't go backwards */
                dout("%p mds time_warp_seq %llu < %u\n",
                     inode, time_warp_seq, ci->i_time_warp_seq);
}

/*
 * Populate an inode based on info from mds.  May be called on new or
 * existing inodes.
 */
int ceph_fill_inode(struct inode *inode, struct page *locked_page,
                    struct ceph_mds_reply_info_in *iinfo,
                    struct ceph_mds_reply_dirfrag *dirinfo,
                    struct ceph_mds_session *session, int cap_fmode,
                    struct ceph_cap_reservation *caps_reservation)
{
        struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
        struct ceph_mds_reply_inode *info = iinfo->in;
        struct ceph_inode_info *ci = ceph_inode(inode);
        int issued, new_issued, info_caps;
        struct timespec64 mtime, atime, ctime;
        struct ceph_buffer *xattr_blob = NULL;
        struct ceph_buffer *old_blob = NULL;
        struct ceph_string *pool_ns = NULL;
        struct ceph_cap *new_cap = NULL;
        int err = 0;
        bool wake = false;
        bool queue_trunc = false;
        bool new_version = false;
        bool fill_inline = false;
        umode_t mode = le32_to_cpu(info->mode);
        dev_t rdev = le32_to_cpu(info->rdev);

        lockdep_assert_held(&mdsc->snap_rwsem);

        dout("%s %p ino %llx.%llx v %llu had %llu\n", __func__,
             inode, ceph_vinop(inode), le64_to_cpu(info->version),
             ci->i_version);

        /* Once I_NEW is cleared, we can't change type or dev numbers */
        if (inode->i_state & I_NEW) {
                inode->i_mode = mode;
        } else {
                if (inode_wrong_type(inode, mode)) {
                        pr_warn_once("inode type changed! (ino %llx.%llx is 0%o, mds says 0%o)\n",
                                     ceph_vinop(inode), inode->i_mode, mode);
                        return -ESTALE;
                }

                if ((S_ISCHR(mode) || S_ISBLK(mode)) && inode->i_rdev != rdev) {
                        pr_warn_once("dev inode rdev changed! (ino %llx.%llx is %u:%u, mds says %u:%u)\n",
                                     ceph_vinop(inode), MAJOR(inode->i_rdev),
                                     MINOR(inode->i_rdev), MAJOR(rdev),
                                     MINOR(rdev));
                        return -ESTALE;
                }
        }

        info_caps = le32_to_cpu(info->cap.caps);

        /* prealloc new cap struct */
        if (info_caps && ceph_snap(inode) == CEPH_NOSNAP) {
                new_cap = ceph_get_cap(mdsc, caps_reservation);
                if (!new_cap)
                        return -ENOMEM;
        }

        /*
         * prealloc xattr data, if it looks like we'll need it.  only
         * if len > 4 (meaning there are actually xattrs; the first 4
         * bytes are the xattr count).
         */
        if (iinfo->xattr_len > 4) {
                xattr_blob = ceph_buffer_new(iinfo->xattr_len, GFP_NOFS);
                if (!xattr_blob)
                        pr_err("%s ENOMEM xattr blob %d bytes\n", __func__,
                               iinfo->xattr_len);
        }

        if (iinfo->pool_ns_len > 0)
                pool_ns = ceph_find_or_create_string(iinfo->pool_ns_data,
                                                     iinfo->pool_ns_len);

        if (ceph_snap(inode) != CEPH_NOSNAP && !ci->i_snapid_map)
                ci->i_snapid_map = ceph_get_snapid_map(mdsc, ceph_snap(inode));

        spin_lock(&ci->i_ceph_lock);

        /*
         * provided version will be odd if inode value is projected,
         * even if stable.  skip the update if we have newer stable
         * info (ours>=theirs, e.g. due to racing mds replies), unless
         * we are getting projected (unstable) info (in which case the
         * version is odd, and we want ours>theirs).
         *   us   them
         *   2    2     skip
         *   3    2     skip
         *   3    3     update
         */
        if (ci->i_version == 0 ||
            ((info->cap.flags & CEPH_CAP_FLAG_AUTH) &&
             le64_to_cpu(info->version) > (ci->i_version & ~1)))
                new_version = true;

        /* Update change_attribute */
        inode_set_max_iversion_raw(inode, iinfo->change_attr);

        __ceph_caps_issued(ci, &issued);
        issued |= __ceph_caps_dirty(ci);
        new_issued = ~issued & info_caps;

        /* directories have fl_stripe_unit set to zero */
        if (le32_to_cpu(info->layout.fl_stripe_unit))
                inode->i_blkbits =
                        fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1;
        else
                inode->i_blkbits = CEPH_BLOCK_SHIFT;

        __ceph_update_quota(ci, iinfo->max_bytes, iinfo->max_files);

        if ((new_version || (new_issued & CEPH_CAP_AUTH_SHARED)) &&
            (issued & CEPH_CAP_AUTH_EXCL) == 0) {
                inode->i_mode = mode;
                inode->i_uid = make_kuid(&init_user_ns, le32_to_cpu(info->uid));
                inode->i_gid = make_kgid(&init_user_ns, le32_to_cpu(info->gid));
                dout("%p mode 0%o uid.gid %d.%d\n", inode, inode->i_mode,
                     from_kuid(&init_user_ns, inode->i_uid),
                     from_kgid(&init_user_ns, inode->i_gid));
                ceph_decode_timespec64(&ci->i_btime, &iinfo->btime);
                ceph_decode_timespec64(&ci->i_snap_btime, &iinfo->snap_btime);
        }

        if ((new_version || (new_issued & CEPH_CAP_LINK_SHARED)) &&
            (issued & CEPH_CAP_LINK_EXCL) == 0)
                set_nlink(inode, le32_to_cpu(info->nlink));

        if (new_version || (new_issued & CEPH_CAP_ANY_RD)) {
                /* be careful with mtime, atime, size */
                ceph_decode_timespec64(&atime, &info->atime);
                ceph_decode_timespec64(&mtime, &info->mtime);
                ceph_decode_timespec64(&ctime, &info->ctime);
                ceph_fill_file_time(inode, issued,
                                le32_to_cpu(info->time_warp_seq),
                                &ctime, &mtime, &atime);
        }

        if (new_version || (info_caps & CEPH_CAP_FILE_SHARED)) {
                ci->i_files = le64_to_cpu(info->files);
                ci->i_subdirs = le64_to_cpu(info->subdirs);
        }

        if (new_version ||
            (new_issued & (CEPH_CAP_ANY_FILE_RD | CEPH_CAP_ANY_FILE_WR))) {
                s64 old_pool = ci->i_layout.pool_id;
                struct ceph_string *old_ns;

                ceph_file_layout_from_legacy(&ci->i_layout, &info->layout);
                old_ns = rcu_dereference_protected(ci->i_layout.pool_ns,
                                        lockdep_is_held(&ci->i_ceph_lock));
                rcu_assign_pointer(ci->i_layout.pool_ns, pool_ns);

                if (ci->i_layout.pool_id != old_pool || pool_ns != old_ns)
                        ci->i_ceph_flags &= ~CEPH_I_POOL_PERM;

                pool_ns = old_ns;

                queue_trunc = ceph_fill_file_size(inode, issued,
                                        le32_to_cpu(info->truncate_seq),
                                        le64_to_cpu(info->truncate_size),
                                        le64_to_cpu(info->size));
                /* only update max_size on auth cap */
                if ((info->cap.flags & CEPH_CAP_FLAG_AUTH) &&
                    ci->i_max_size != le64_to_cpu(info->max_size)) {
                        dout("max_size %lld -> %llu\n", ci->i_max_size,
                                        le64_to_cpu(info->max_size));
                        ci->i_max_size = le64_to_cpu(info->max_size);
                }
        }

        /* layout and rstat are not tracked by capability, update them if
         * the inode info is from auth mds */
        if (new_version || (info->cap.flags & CEPH_CAP_FLAG_AUTH)) {
                if (S_ISDIR(inode->i_mode)) {
                        ci->i_dir_layout = iinfo->dir_layout;
                        ci->i_rbytes = le64_to_cpu(info->rbytes);
                        ci->i_rfiles = le64_to_cpu(info->rfiles);
                        ci->i_rsubdirs = le64_to_cpu(info->rsubdirs);
                        ci->i_dir_pin = iinfo->dir_pin;
                        ci->i_rsnaps = iinfo->rsnaps;
                        ceph_decode_timespec64(&ci->i_rctime, &info->rctime);
                }
        }

        /* xattrs */
        /* note that if i_xattrs.len <= 4, i_xattrs.data will still be NULL. */
        if ((ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL))  &&
            le64_to_cpu(info->xattr_version) > ci->i_xattrs.version) {
                if (ci->i_xattrs.blob)
                        old_blob = ci->i_xattrs.blob;
                ci->i_xattrs.blob = xattr_blob;
                if (xattr_blob)
                        memcpy(ci->i_xattrs.blob->vec.iov_base,
                               iinfo->xattr_data, iinfo->xattr_len);
                ci->i_xattrs.version = le64_to_cpu(info->xattr_version);
                ceph_forget_all_cached_acls(inode);
                ceph_security_invalidate_secctx(inode);
                xattr_blob = NULL;
        }

        /* finally update i_version */
        if (le64_to_cpu(info->version) > ci->i_version)
                ci->i_version = le64_to_cpu(info->version);

        inode->i_mapping->a_ops = &ceph_aops;

        switch (inode->i_mode & S_IFMT) {
        case S_IFIFO:
        case S_IFBLK:
        case S_IFCHR:
        case S_IFSOCK:
                inode->i_blkbits = PAGE_SHIFT;
                init_special_inode(inode, inode->i_mode, rdev);
                inode->i_op = &ceph_file_iops;
                break;
        case S_IFREG:
                inode->i_op = &ceph_file_iops;
                inode->i_fop = &ceph_file_fops;
                break;
        case S_IFLNK:
                inode->i_op = &ceph_symlink_iops;
                if (!ci->i_symlink) {
                        u32 symlen = iinfo->symlink_len;
                        char *sym;

                        spin_unlock(&ci->i_ceph_lock);

                        if (symlen != i_size_read(inode)) {
                                pr_err("%s %llx.%llx BAD symlink "
                                        "size %lld\n", __func__,
                                        ceph_vinop(inode),
                                        i_size_read(inode));
                                i_size_write(inode, symlen);
                                inode->i_blocks = calc_inode_blocks(symlen);
                        }

                        err = -ENOMEM;
                        sym = kstrndup(iinfo->symlink, symlen, GFP_NOFS);
                        if (!sym)
                                goto out;

                        spin_lock(&ci->i_ceph_lock);
                        if (!ci->i_symlink)
                                ci->i_symlink = sym;
                        else
                                kfree(sym); /* lost a race */
                }
                inode->i_link = ci->i_symlink;
                break;
        case S_IFDIR:
                inode->i_op = &ceph_dir_iops;
                inode->i_fop = &ceph_dir_fops;
                break;
        default:
                pr_err("%s %llx.%llx BAD mode 0%o\n", __func__,
                       ceph_vinop(inode), inode->i_mode);
        }

        /* were we issued a capability? */
        if (info_caps) {
                if (ceph_snap(inode) == CEPH_NOSNAP) {
                        ceph_add_cap(inode, session,
                                     le64_to_cpu(info->cap.cap_id),
                                     info_caps,
                                     le32_to_cpu(info->cap.wanted),
                                     le32_to_cpu(info->cap.seq),
                                     le32_to_cpu(info->cap.mseq),
                                     le64_to_cpu(info->cap.realm),
                                     info->cap.flags, &new_cap);

                        /* set dir completion flag? */
                        if (S_ISDIR(inode->i_mode) &&
                            ci->i_files == 0 && ci->i_subdirs == 0 &&
                            (info_caps & CEPH_CAP_FILE_SHARED) &&
                            (issued & CEPH_CAP_FILE_EXCL) == 0 &&
                            !__ceph_dir_is_complete(ci)) {
                                dout(" marking %p complete (empty)\n", inode);
                                i_size_write(inode, 0);
                                __ceph_dir_set_complete(ci,
                                        atomic64_read(&ci->i_release_count),
                                        atomic64_read(&ci->i_ordered_count));
                        }

                        wake = true;
                } else {
                        dout(" %p got snap_caps %s\n", inode,
                             ceph_cap_string(info_caps));
                        ci->i_snap_caps |= info_caps;
                }
        }

        if (iinfo->inline_version > 0 &&
            iinfo->inline_version >= ci->i_inline_version) {
                int cache_caps = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
                ci->i_inline_version = iinfo->inline_version;
                if (ci->i_inline_version != CEPH_INLINE_NONE &&
                    (locked_page || (info_caps & cache_caps)))
                        fill_inline = true;
        }

        if (cap_fmode >= 0) {
                if (!info_caps)
                        pr_warn("mds issued no caps on %llx.%llx\n",
                                ceph_vinop(inode));
                __ceph_touch_fmode(ci, mdsc, cap_fmode);
        }

        spin_unlock(&ci->i_ceph_lock);

        if (fill_inline)
                ceph_fill_inline_data(inode, locked_page,
                                      iinfo->inline_data, iinfo->inline_len);

        if (wake)
                wake_up_all(&ci->i_cap_wq);

        /* queue truncate if we saw i_size decrease */
        if (queue_trunc)
                ceph_queue_vmtruncate(inode);

        /* populate frag tree */
        if (S_ISDIR(inode->i_mode))
                ceph_fill_fragtree(inode, &info->fragtree, dirinfo);

        /* update delegation info? */
        if (dirinfo)
                ceph_fill_dirfrag(inode, dirinfo);

        err = 0;
out:
        if (new_cap)
                ceph_put_cap(mdsc, new_cap);
        ceph_buffer_put(old_blob);
        ceph_buffer_put(xattr_blob);
        ceph_put_string(pool_ns);
        return err;
}

/*
 * caller should hold session s_mutex and dentry->d_lock.
 */
static void __update_dentry_lease(struct inode *dir, struct dentry *dentry,
                                  struct ceph_mds_reply_lease *lease,
                                  struct ceph_mds_session *session,
                                  unsigned long from_time,
                                  struct ceph_mds_session **old_lease_session)
{
        struct ceph_dentry_info *di = ceph_dentry(dentry);
        unsigned mask = le16_to_cpu(lease->mask);
        long unsigned duration = le32_to_cpu(lease->duration_ms);
        long unsigned ttl = from_time + (duration * HZ) / 1000;
        long unsigned half_ttl = from_time + (duration * HZ / 2) / 1000;

        dout("update_dentry_lease %p duration %lu ms ttl %lu\n",
             dentry, duration, ttl);

        /* only track leases on regular dentries */
        if (ceph_snap(dir) != CEPH_NOSNAP)
                return;

        if (mask & CEPH_LEASE_PRIMARY_LINK)
                di->flags |= CEPH_DENTRY_PRIMARY_LINK;
        else
                di->flags &= ~CEPH_DENTRY_PRIMARY_LINK;

        di->lease_shared_gen = atomic_read(&ceph_inode(dir)->i_shared_gen);
        if (!(mask & CEPH_LEASE_VALID)) {
                __ceph_dentry_dir_lease_touch(di);
                return;
        }

        if (di->lease_gen == atomic_read(&session->s_cap_gen) &&
            time_before(ttl, di->time))
                return;  /* we already have a newer lease. */

        if (di->lease_session && di->lease_session != session) {
                *old_lease_session = di->lease_session;
                di->lease_session = NULL;
        }

        if (!di->lease_session)
                di->lease_session = ceph_get_mds_session(session);
        di->lease_gen = atomic_read(&session->s_cap_gen);
        di->lease_seq = le32_to_cpu(lease->seq);
        di->lease_renew_after = half_ttl;
        di->lease_renew_from = 0;
        di->time = ttl;

        __ceph_dentry_lease_touch(di);
}

static inline void update_dentry_lease(struct inode *dir, struct dentry *dentry,
                                        struct ceph_mds_reply_lease *lease,
                                        struct ceph_mds_session *session,
                                        unsigned long from_time)
{
        struct ceph_mds_session *old_lease_session = NULL;
        spin_lock(&dentry->d_lock);
        __update_dentry_lease(dir, dentry, lease, session, from_time,
                              &old_lease_session);
        spin_unlock(&dentry->d_lock);
        ceph_put_mds_session(old_lease_session);
}

/*
 * update dentry lease without having parent inode locked
 */
static void update_dentry_lease_careful(struct dentry *dentry,
                                        struct ceph_mds_reply_lease *lease,
                                        struct ceph_mds_session *session,
                                        unsigned long from_time,
                                        char *dname, u32 dname_len,
                                        struct ceph_vino *pdvino,
                                        struct ceph_vino *ptvino)

{
        struct inode *dir;
        struct ceph_mds_session *old_lease_session = NULL;

        spin_lock(&dentry->d_lock);
        /* make sure dentry's name matches target */
        if (dentry->d_name.len != dname_len ||
            memcmp(dentry->d_name.name, dname, dname_len))
                goto out_unlock;

        dir = d_inode(dentry->d_parent);
        /* make sure parent matches dvino */
        if (!ceph_ino_compare(dir, pdvino))
                goto out_unlock;

        /* make sure dentry's inode matches target. NULL ptvino means that
         * we expect a negative dentry */
        if (ptvino) {
                if (d_really_is_negative(dentry))
                        goto out_unlock;
                if (!ceph_ino_compare(d_inode(dentry), ptvino))
                        goto out_unlock;
        } else {
                if (d_really_is_positive(dentry))
                        goto out_unlock;
        }

        __update_dentry_lease(dir, dentry, lease, session,
                              from_time, &old_lease_session);
out_unlock:
        spin_unlock(&dentry->d_lock);
        ceph_put_mds_session(old_lease_session);
}

/*
 * splice a dentry to an inode.
 * caller must hold directory i_mutex for this to be safe.
 */
static int splice_dentry(struct dentry **pdn, struct inode *in)
{
        struct dentry *dn = *pdn;
        struct dentry *realdn;

        BUG_ON(d_inode(dn));

        if (S_ISDIR(in->i_mode)) {
                /* If inode is directory, d_splice_alias() below will remove
                 * 'realdn' from its origin parent. We need to ensure that
                 * origin parent's readdir cache will not reference 'realdn'
                 */
                realdn = d_find_any_alias(in);
                if (realdn) {
                        struct ceph_dentry_info *di = ceph_dentry(realdn);
                        spin_lock(&realdn->d_lock);

                        realdn->d_op->d_prune(realdn);

                        di->time = jiffies;
                        di->lease_shared_gen = 0;
                        di->offset = 0;

                        spin_unlock(&realdn->d_lock);
                        dput(realdn);
                }
        }

        /* dn must be unhashed */
        if (!d_unhashed(dn))
                d_drop(dn);
        realdn = d_splice_alias(in, dn);
        if (IS_ERR(realdn)) {
                pr_err("splice_dentry error %ld %p inode %p ino %llx.%llx\n",
                       PTR_ERR(realdn), dn, in, ceph_vinop(in));
                return PTR_ERR(realdn);
        }

        if (realdn) {
                dout("dn %p (%d) spliced with %p (%d) "
                     "inode %p ino %llx.%llx\n",
                     dn, d_count(dn),
                     realdn, d_count(realdn),
                     d_inode(realdn), ceph_vinop(d_inode(realdn)));
                dput(dn);
                *pdn = realdn;
        } else {
                BUG_ON(!ceph_dentry(dn));
                dout("dn %p attached to %p ino %llx.%llx\n",
                     dn, d_inode(dn), ceph_vinop(d_inode(dn)));
        }
        return 0;
}

/*
 * Incorporate results into the local cache.  This is either just
 * one inode, or a directory, dentry, and possibly linked-to inode (e.g.,
 * after a lookup).
 *
 * A reply may contain
 *         a directory inode along with a dentry.
 *  and/or a target inode
 *
 * Called with snap_rwsem (read).
 */
int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
{
        struct ceph_mds_session *session = req->r_session;
        struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
        struct inode *in = NULL;
        struct ceph_vino tvino, dvino;
        struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
        int err = 0;

        dout("fill_trace %p is_dentry %d is_target %d\n", req,
             rinfo->head->is_dentry, rinfo->head->is_target);

        if (!rinfo->head->is_target && !rinfo->head->is_dentry) {
                dout("fill_trace reply is empty!\n");
                if (rinfo->head->result == 0 && req->r_parent)
                        ceph_invalidate_dir_request(req);
                return 0;
        }

        if (rinfo->head->is_dentry) {
                struct inode *dir = req->r_parent;

                if (dir) {
                        err = ceph_fill_inode(dir, NULL, &rinfo->diri,
                                              rinfo->dirfrag, session, -1,
                                              &req->r_caps_reservation);
                        if (err < 0)
                                goto done;
                } else {
                        WARN_ON_ONCE(1);
                }

                if (dir && req->r_op == CEPH_MDS_OP_LOOKUPNAME &&
                    test_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags) &&
                    !test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
                        struct qstr dname;
                        struct dentry *dn, *parent;

                        BUG_ON(!rinfo->head->is_target);
                        BUG_ON(req->r_dentry);

                        parent = d_find_any_alias(dir);
                        BUG_ON(!parent);

                        dname.name = rinfo->dname;
                        dname.len = rinfo->dname_len;
                        dname.hash = full_name_hash(parent, dname.name, dname.len);
                        tvino.ino = le64_to_cpu(rinfo->targeti.in->ino);
                        tvino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
retry_lookup:
                        dn = d_lookup(parent, &dname);
                        dout("d_lookup on parent=%p name=%.*s got %p\n",
                             parent, dname.len, dname.name, dn);

                        if (!dn) {
                                dn = d_alloc(parent, &dname);
                                dout("d_alloc %p '%.*s' = %p\n", parent,
                                     dname.len, dname.name, dn);
                                if (!dn) {
                                        dput(parent);
                                        err = -ENOMEM;
                                        goto done;
                                }
                                err = 0;
                        } else if (d_really_is_positive(dn) &&
                                   (ceph_ino(d_inode(dn)) != tvino.ino ||
                                    ceph_snap(d_inode(dn)) != tvino.snap)) {
                                dout(" dn %p points to wrong inode %p\n",
                                     dn, d_inode(dn));
                                ceph_dir_clear_ordered(dir);
                                d_delete(dn);
                                dput(dn);
                                goto retry_lookup;
                        }

                        req->r_dentry = dn;
                        dput(parent);
                }
        }

        if (rinfo->head->is_target) {
                /* Should be filled in by handle_reply */
                BUG_ON(!req->r_target_inode);

                in = req->r_target_inode;
                err = ceph_fill_inode(in, req->r_locked_page, &rinfo->targeti,
                                NULL, session,
                                (!test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags) &&
                                 !test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags) &&
                                 rinfo->head->result == 0) ?  req->r_fmode : -1,
                                &req->r_caps_reservation);
                if (err < 0) {
                        pr_err("ceph_fill_inode badness %p %llx.%llx\n",
                                in, ceph_vinop(in));
                        req->r_target_inode = NULL;
                        if (in->i_state & I_NEW)
                                discard_new_inode(in);
                        else
                                iput(in);
                        goto done;
                }
                if (in->i_state & I_NEW)
                        unlock_new_inode(in);
        }

        /*
         * ignore null lease/binding on snapdir ENOENT, or else we
         * will have trouble splicing in the virtual snapdir later
         */
        if (rinfo->head->is_dentry &&
            !test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags) &&
            test_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags) &&
            (rinfo->head->is_target || strncmp(req->r_dentry->d_name.name,
                                               fsc->mount_options->snapdir_name,
                                               req->r_dentry->d_name.len))) {
                /*
                 * lookup link rename   : null -> possibly existing inode
                 * mknod symlink mkdir  : null -> new inode
                 * unlink               : linked -> null
                 */
                struct inode *dir = req->r_parent;
                struct dentry *dn = req->r_dentry;
                bool have_dir_cap, have_lease;

                BUG_ON(!dn);
                BUG_ON(!dir);
                BUG_ON(d_inode(dn->d_parent) != dir);

                dvino.ino = le64_to_cpu(rinfo->diri.in->ino);
                dvino.snap = le64_to_cpu(rinfo->diri.in->snapid);

                BUG_ON(ceph_ino(dir) != dvino.ino);
                BUG_ON(ceph_snap(dir) != dvino.snap);

                /* do we have a lease on the whole dir? */
                have_dir_cap =
                        (le32_to_cpu(rinfo->diri.in->cap.caps) &
                         CEPH_CAP_FILE_SHARED);

                /* do we have a dn lease? */
                have_lease = have_dir_cap ||
                        le32_to_cpu(rinfo->dlease->duration_ms);
                if (!have_lease)
                        dout("fill_trace  no dentry lease or dir cap\n");

                /* rename? */
                if (req->r_old_dentry && req->r_op == CEPH_MDS_OP_RENAME) {
                        struct inode *olddir = req->r_old_dentry_dir;
                        BUG_ON(!olddir);

                        dout(" src %p '%pd' dst %p '%pd'\n",
                             req->r_old_dentry,
                             req->r_old_dentry,
                             dn, dn);
                        dout("fill_trace doing d_move %p -> %p\n",
                             req->r_old_dentry, dn);

                        /* d_move screws up sibling dentries' offsets */
                        ceph_dir_clear_ordered(dir);
                        ceph_dir_clear_ordered(olddir);

                        d_move(req->r_old_dentry, dn);
                        dout(" src %p '%pd' dst %p '%pd'\n",
                             req->r_old_dentry,
                             req->r_old_dentry,
                             dn, dn);

                        /* ensure target dentry is invalidated, despite
                           rehashing bug in vfs_rename_dir */
                        ceph_invalidate_dentry_lease(dn);

                        dout("dn %p gets new offset %lld\n", req->r_old_dentry,
                             ceph_dentry(req->r_old_dentry)->offset);

                        /* swap r_dentry and r_old_dentry in case that
                         * splice_dentry() gets called later. This is safe
                         * because no other place will use them */
                        req->r_dentry = req->r_old_dentry;
                        req->r_old_dentry = dn;
                        dn = req->r_dentry;
                }

                /* null dentry? */
                if (!rinfo->head->is_target) {
                        dout("fill_trace null dentry\n");
                        if (d_really_is_positive(dn)) {
                                dout("d_delete %p\n", dn);
                                ceph_dir_clear_ordered(dir);
                                d_delete(dn);
                        } else if (have_lease) {
                                if (d_unhashed(dn))
                                        d_add(dn, NULL);
                                update_dentry_lease(dir, dn,
                                                    rinfo->dlease, session,
                                                    req->r_request_started);
                        }
                        goto done;
                }

                /* attach proper inode */
                if (d_really_is_negative(dn)) {
                        ceph_dir_clear_ordered(dir);
                        ihold(in);
                        err = splice_dentry(&req->r_dentry, in);
                        if (err < 0)
                                goto done;
                        dn = req->r_dentry;  /* may have spliced */
                } else if (d_really_is_positive(dn) && d_inode(dn) != in) {
                        dout(" %p links to %p %llx.%llx, not %llx.%llx\n",
                             dn, d_inode(dn), ceph_vinop(d_inode(dn)),
                             ceph_vinop(in));
                        d_invalidate(dn);
                        have_lease = false;
                }

                if (have_lease) {
                        update_dentry_lease(dir, dn,
                                            rinfo->dlease, session,
                                            req->r_request_started);
                }
                dout(" final dn %p\n", dn);
        } else if ((req->r_op == CEPH_MDS_OP_LOOKUPSNAP ||
                    req->r_op == CEPH_MDS_OP_MKSNAP) &&
                   test_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags) &&
                   !test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
                struct inode *dir = req->r_parent;

                /* fill out a snapdir LOOKUPSNAP dentry */
                BUG_ON(!dir);
                BUG_ON(ceph_snap(dir) != CEPH_SNAPDIR);
                BUG_ON(!req->r_dentry);
                dout(" linking snapped dir %p to dn %p\n", in, req->r_dentry);
                ceph_dir_clear_ordered(dir);
                ihold(in);
                err = splice_dentry(&req->r_dentry, in);
                if (err < 0)
                        goto done;
        } else if (rinfo->head->is_dentry && req->r_dentry) {
                /* parent inode is not locked, be carefull */
                struct ceph_vino *ptvino = NULL;
                dvino.ino = le64_to_cpu(rinfo->diri.in->ino);
                dvino.snap = le64_to_cpu(rinfo->diri.in->snapid);
                if (rinfo->head->is_target) {
                        tvino.ino = le64_to_cpu(rinfo->targeti.in->ino);
                        tvino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
                        ptvino = &tvino;
                }
                update_dentry_lease_careful(req->r_dentry, rinfo->dlease,
                                            session, req->r_request_started,
                                            rinfo->dname, rinfo->dname_len,
                                            &dvino, ptvino);
        }
done:
        dout("fill_trace done err=%d\n", err);
        return err;
}

/*
 * Prepopulate our cache with readdir results, leases, etc.
 */
static int readdir_prepopulate_inodes_only(struct ceph_mds_request *req,
                                           struct ceph_mds_session *session)
{
        struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
        int i, err = 0;

        for (i = 0; i < rinfo->dir_nr; i++) {
                struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
                struct ceph_vino vino;
                struct inode *in;
                int rc;

                vino.ino = le64_to_cpu(rde->inode.in->ino);
                vino.snap = le64_to_cpu(rde->inode.in->snapid);

                in = ceph_get_inode(req->r_dentry->d_sb, vino);
                if (IS_ERR(in)) {
                        err = PTR_ERR(in);
                        dout("new_inode badness got %d\n", err);
                        continue;
                }
                rc = ceph_fill_inode(in, NULL, &rde->inode, NULL, session,
                                     -1, &req->r_caps_reservation);
                if (rc < 0) {
                        pr_err("ceph_fill_inode badness on %p got %d\n",
                               in, rc);
                        err = rc;
                        if (in->i_state & I_NEW) {
                                ihold(in);
                                discard_new_inode(in);
                        }
                } else if (in->i_state & I_NEW) {
                        unlock_new_inode(in);
                }

                iput(in);
        }

        return err;
}

void ceph_readdir_cache_release(struct ceph_readdir_cache_control *ctl)
{
        if (ctl->page) {
                kunmap(ctl->page);
                put_page(ctl->page);
                ctl->page = NULL;
        }
}

static int fill_readdir_cache(struct inode *dir, struct dentry *dn,
                              struct ceph_readdir_cache_control *ctl,
                              struct ceph_mds_request *req)
{
        struct ceph_inode_info *ci = ceph_inode(dir);
        unsigned nsize = PAGE_SIZE / sizeof(struct dentry*);
        unsigned idx = ctl->index % nsize;
        pgoff_t pgoff = ctl->index / nsize;

        if (!ctl->page || pgoff != page_index(ctl->page)) {
                ceph_readdir_cache_release(ctl);
                if (idx == 0)
                        ctl->page = grab_cache_page(&dir->i_data, pgoff);
                else
                        ctl->page = find_lock_page(&dir->i_data, pgoff);
                if (!ctl->page) {
                        ctl->index = -1;
                        return idx == 0 ? -ENOMEM : 0;
                }
                /* reading/filling the cache are serialized by
                 * i_mutex, no need to use page lock */
                unlock_page(ctl->page);
                ctl->dentries = kmap(ctl->page);
                if (idx == 0)
                        memset(ctl->dentries, 0, PAGE_SIZE);
        }

        if (req->r_dir_release_cnt == atomic64_read(&ci->i_release_count) &&
            req->r_dir_ordered_cnt == atomic64_read(&ci->i_ordered_count)) {
                dout("readdir cache dn %p idx %d\n", dn, ctl->index);
                ctl->dentries[idx] = dn;
                ctl->index++;
        } else {
                dout("disable readdir cache\n");
                ctl->index = -1;
        }
        return 0;
}

int ceph_readdir_prepopulate(struct ceph_mds_request *req,
                             struct ceph_mds_session *session)
{
        struct dentry *parent = req->r_dentry;
        struct ceph_inode_info *ci = ceph_inode(d_inode(parent));
        struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
        struct qstr dname;
        struct dentry *dn;
        struct inode *in;
        int err = 0, skipped = 0, ret, i;
        u32 frag = le32_to_cpu(req->r_args.readdir.frag);
        u32 last_hash = 0;
        u32 fpos_offset;
        struct ceph_readdir_cache_control cache_ctl = {};

        if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
                return readdir_prepopulate_inodes_only(req, session);

        if (rinfo->hash_order) {
                if (req->r_path2) {
                        last_hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
                                                  req->r_path2,
                                                  strlen(req->r_path2));
                        last_hash = ceph_frag_value(last_hash);
                } else if (rinfo->offset_hash) {
                        /* mds understands offset_hash */
                        WARN_ON_ONCE(req->r_readdir_offset != 2);
                        last_hash = le32_to_cpu(req->r_args.readdir.offset_hash);
                }
        }

        if (rinfo->dir_dir &&
            le32_to_cpu(rinfo->dir_dir->frag) != frag) {
                dout("readdir_prepopulate got new frag %x -> %x\n",
                     frag, le32_to_cpu(rinfo->dir_dir->frag));
                frag = le32_to_cpu(rinfo->dir_dir->frag);
                if (!rinfo->hash_order)
                        req->r_readdir_offset = 2;
        }

        if (le32_to_cpu(rinfo->head->op) == CEPH_MDS_OP_LSSNAP) {
                dout("readdir_prepopulate %d items under SNAPDIR dn %p\n",
                     rinfo->dir_nr, parent);
        } else {
                dout("readdir_prepopulate %d items under dn %p\n",
                     rinfo->dir_nr, parent);
                if (rinfo->dir_dir)
                        ceph_fill_dirfrag(d_inode(parent), rinfo->dir_dir);

                if (ceph_frag_is_leftmost(frag) &&
                    req->r_readdir_offset == 2 &&
                    !(rinfo->hash_order && last_hash)) {
                        /* note dir version at start of readdir so we can
                         * tell if any dentries get dropped */
                        req->r_dir_release_cnt =
                                atomic64_read(&ci->i_release_count);
                        req->r_dir_ordered_cnt =
                                atomic64_read(&ci->i_ordered_count);
                        req->r_readdir_cache_idx = 0;
                }
        }

        cache_ctl.index = req->r_readdir_cache_idx;
        fpos_offset = req->r_readdir_offset;

        /* FIXME: release caps/leases if error occurs */
        for (i = 0; i < rinfo->dir_nr; i++) {
                struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
                struct ceph_vino tvino;

                dname.name = rde->name;
                dname.len = rde->name_len;
                dname.hash = full_name_hash(parent, dname.name, dname.len);

                tvino.ino = le64_to_cpu(rde->inode.in->ino);
                tvino.snap = le64_to_cpu(rde->inode.in->snapid);

                if (rinfo->hash_order) {
                        u32 hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
                                                 rde->name, rde->name_len);
                        hash = ceph_frag_value(hash);
                        if (hash != last_hash)
                                fpos_offset = 2;
                        last_hash = hash;
                        rde->offset = ceph_make_fpos(hash, fpos_offset++, true);
                } else {
                        rde->offset = ceph_make_fpos(frag, fpos_offset++, false);
                }

retry_lookup:
                dn = d_lookup(parent, &dname);
                dout("d_lookup on parent=%p name=%.*s got %p\n",
                     parent, dname.len, dname.name, dn);

                if (!dn) {
                        dn = d_alloc(parent, &dname);
                        dout("d_alloc %p '%.*s' = %p\n", parent,
                             dname.len, dname.name, dn);
                        if (!dn) {
                                dout("d_alloc badness\n");
                                err = -ENOMEM;
                                goto out;
                        }
                } else if (d_really_is_positive(dn) &&
                           (ceph_ino(d_inode(dn)) != tvino.ino ||
                            ceph_snap(d_inode(dn)) != tvino.snap)) {
                        struct ceph_dentry_info *di = ceph_dentry(dn);
                        dout(" dn %p points to wrong inode %p\n",
                             dn, d_inode(dn));

                        spin_lock(&dn->d_lock);
                        if (di->offset > 0 &&
                            di->lease_shared_gen ==
                            atomic_read(&ci->i_shared_gen)) {
                                __ceph_dir_clear_ordered(ci);
                                di->offset = 0;
                        }
                        spin_unlock(&dn->d_lock);

                        d_delete(dn);
                        dput(dn);
                        goto retry_lookup;
                }

                /* inode */
                if (d_really_is_positive(dn)) {
                        in = d_inode(dn);
                } else {
                        in = ceph_get_inode(parent->d_sb, tvino);
                        if (IS_ERR(in)) {
                                dout("new_inode badness\n");
                                d_drop(dn);
                                dput(dn);
                                err = PTR_ERR(in);
                                goto out;
                        }
                }

                ret = ceph_fill_inode(in, NULL, &rde->inode, NULL, session,
                                      -1, &req->r_caps_reservation);
                if (ret < 0) {
                        pr_err("ceph_fill_inode badness on %p\n", in);
                        if (d_really_is_negative(dn)) {
                                if (in->i_state & I_NEW) {
                                        ihold(in);
                                        discard_new_inode(in);
                                }
                                iput(in);
                        }
                        d_drop(dn);
                        err = ret;
                        goto next_item;
                }
                if (in->i_state & I_NEW)
                        unlock_new_inode(in);

                if (d_really_is_negative(dn)) {
                        if (ceph_security_xattr_deadlock(in)) {
                                dout(" skip splicing dn %p to inode %p"
                                     " (security xattr deadlock)\n", dn, in);
                                iput(in);
                                skipped++;
                                goto next_item;
                        }

                        err = splice_dentry(&dn, in);
                        if (err < 0)
                                goto next_item;
                }

                ceph_dentry(dn)->offset = rde->offset;

                update_dentry_lease(d_inode(parent), dn,
                                    rde->lease, req->r_session,
                                    req->r_request_started);

                if (err == 0 && skipped == 0 && cache_ctl.index >= 0) {
                        ret = fill_readdir_cache(d_inode(parent), dn,
                                                 &cache_ctl, req);
                        if (ret < 0)
                                err = ret;
                }
next_item:
                dput(dn);
        }
out:
        if (err == 0 && skipped == 0) {
                set_bit(CEPH_MDS_R_DID_PREPOPULATE, &req->r_req_flags);
                req->r_readdir_cache_idx = cache_ctl.index;
        }
        ceph_readdir_cache_release(&cache_ctl);
        dout("readdir_prepopulate done\n");
        return err;
}

bool ceph_inode_set_size(struct inode *inode, loff_t size)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        bool ret;

        spin_lock(&ci->i_ceph_lock);
        dout("set_size %p %llu -> %llu\n", inode, i_size_read(inode), size);
        i_size_write(inode, size);
        inode->i_blocks = calc_inode_blocks(size);

        ret = __ceph_should_report_size(ci);

        spin_unlock(&ci->i_ceph_lock);
        return ret;
}

void ceph_queue_inode_work(struct inode *inode, int work_bit)
{
        struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
        struct ceph_inode_info *ci = ceph_inode(inode);
        set_bit(work_bit, &ci->i_work_mask);

        ihold(inode);
        if (queue_work(fsc->inode_wq, &ci->i_work)) {
                dout("queue_inode_work %p, mask=%lx\n", inode, ci->i_work_mask);
        } else {
                dout("queue_inode_work %p already queued, mask=%lx\n",
                     inode, ci->i_work_mask);
                iput(inode);
        }
}

static void ceph_do_invalidate_pages(struct inode *inode)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
        u32 orig_gen;
        int check = 0;

        mutex_lock(&ci->i_truncate_mutex);

        if (READ_ONCE(fsc->mount_state) >= CEPH_MOUNT_SHUTDOWN) {
                pr_warn_ratelimited("invalidate_pages %p %lld forced umount\n",
                                    inode, ceph_ino(inode));
                mapping_set_error(inode->i_mapping, -EIO);
                truncate_pagecache(inode, 0);
                mutex_unlock(&ci->i_truncate_mutex);
                goto out;
        }

        spin_lock(&ci->i_ceph_lock);
        dout("invalidate_pages %p gen %d revoking %d\n", inode,
             ci->i_rdcache_gen, ci->i_rdcache_revoking);
        if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
                if (__ceph_caps_revoking_other(ci, NULL, CEPH_CAP_FILE_CACHE))
                        check = 1;
                spin_unlock(&ci->i_ceph_lock);
                mutex_unlock(&ci->i_truncate_mutex);
                goto out;
        }
        orig_gen = ci->i_rdcache_gen;
        spin_unlock(&ci->i_ceph_lock);

        ceph_fscache_invalidate(inode);
        if (invalidate_inode_pages2(inode->i_mapping) < 0) {
                pr_err("invalidate_pages %p fails\n", inode);
        }

        spin_lock(&ci->i_ceph_lock);
        if (orig_gen == ci->i_rdcache_gen &&
            orig_gen == ci->i_rdcache_revoking) {
                dout("invalidate_pages %p gen %d successful\n", inode,
                     ci->i_rdcache_gen);
                ci->i_rdcache_revoking--;
                check = 1;
        } else {
                dout("invalidate_pages %p gen %d raced, now %d revoking %d\n",
                     inode, orig_gen, ci->i_rdcache_gen,
                     ci->i_rdcache_revoking);
                if (__ceph_caps_revoking_other(ci, NULL, CEPH_CAP_FILE_CACHE))
                        check = 1;
        }
        spin_unlock(&ci->i_ceph_lock);
        mutex_unlock(&ci->i_truncate_mutex);
out:
        if (check)
                ceph_check_caps(ci, 0, NULL);
}

/*
 * Make sure any pending truncation is applied before doing anything
 * that may depend on it.
 */
void __ceph_do_pending_vmtruncate(struct inode *inode)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        u64 to;
        int wrbuffer_refs, finish = 0;

        mutex_lock(&ci->i_truncate_mutex);
retry:
        spin_lock(&ci->i_ceph_lock);
        if (ci->i_truncate_pending == 0) {
                dout("__do_pending_vmtruncate %p none pending\n", inode);
                spin_unlock(&ci->i_ceph_lock);
                mutex_unlock(&ci->i_truncate_mutex);
                return;
        }

        /*
         * make sure any dirty snapped pages are flushed before we
         * possibly truncate them.. so write AND block!
         */
        if (ci->i_wrbuffer_ref_head < ci->i_wrbuffer_ref) {
                spin_unlock(&ci->i_ceph_lock);
                dout("__do_pending_vmtruncate %p flushing snaps first\n",
                     inode);
                filemap_write_and_wait_range(&inode->i_data, 0,
                                             inode->i_sb->s_maxbytes);
                goto retry;
        }

        /* there should be no reader or writer */
        WARN_ON_ONCE(ci->i_rd_ref || ci->i_wr_ref);

        to = ci->i_truncate_size;
        wrbuffer_refs = ci->i_wrbuffer_ref;
        dout("__do_pending_vmtruncate %p (%d) to %lld\n", inode,
             ci->i_truncate_pending, to);
        spin_unlock(&ci->i_ceph_lock);

        truncate_pagecache(inode, to);

        spin_lock(&ci->i_ceph_lock);
        if (to == ci->i_truncate_size) {
                ci->i_truncate_pending = 0;
                finish = 1;
        }
        spin_unlock(&ci->i_ceph_lock);
        if (!finish)
                goto retry;

        mutex_unlock(&ci->i_truncate_mutex);

        if (wrbuffer_refs == 0)
                ceph_check_caps(ci, 0, NULL);

        wake_up_all(&ci->i_cap_wq);
}

static void ceph_inode_work(struct work_struct *work)
{
        struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
                                                 i_work);
        struct inode *inode = &ci->vfs_inode;

        if (test_and_clear_bit(CEPH_I_WORK_WRITEBACK, &ci->i_work_mask)) {
                dout("writeback %p\n", inode);
                filemap_fdatawrite(&inode->i_data);
        }
        if (test_and_clear_bit(CEPH_I_WORK_INVALIDATE_PAGES, &ci->i_work_mask))
                ceph_do_invalidate_pages(inode);

        if (test_and_clear_bit(CEPH_I_WORK_VMTRUNCATE, &ci->i_work_mask))
                __ceph_do_pending_vmtruncate(inode);

        if (test_and_clear_bit(CEPH_I_WORK_CHECK_CAPS, &ci->i_work_mask))
                ceph_check_caps(ci, 0, NULL);

        if (test_and_clear_bit(CEPH_I_WORK_FLUSH_SNAPS, &ci->i_work_mask))
                ceph_flush_snaps(ci, NULL);

        iput(inode);
}

/*
 * symlinks
 */
static const struct inode_operations ceph_symlink_iops = {
        .get_link = simple_get_link,
        .setattr = ceph_setattr,
        .getattr = ceph_getattr,
        .listxattr = ceph_listxattr,
};

int __ceph_setattr(struct inode *inode, struct iattr *attr)
{
        struct ceph_inode_info *ci = ceph_inode(inode);
        unsigned int ia_valid = attr->ia_valid;
        struct ceph_mds_request *req;
        struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
        struct ceph_cap_flush *prealloc_cf;
        int issued;
        int release = 0, dirtied = 0;
        int mask = 0;
        int err = 0;
        int inode_dirty_flags = 0;
        bool lock_snap_rwsem = false;

        prealloc_cf = ceph_alloc_cap_flush();
        if (!prealloc_cf)
                return -ENOMEM;

        req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETATTR,
                                       USE_AUTH_MDS);
        if (IS_ERR(req)) {
                ceph_free_cap_flush(prealloc_cf);
                return PTR_ERR(req);
        }

        spin_lock(&ci->i_ceph_lock);
        issued = __ceph_caps_issued(ci, NULL);

        if (!ci->i_head_snapc &&
            (issued & (CEPH_CAP_ANY_EXCL | CEPH_CAP_FILE_WR))) {
                lock_snap_rwsem = true;
                if (!down_read_trylock(&mdsc->snap_rwsem)) {
                        spin_unlock(&ci->i_ceph_lock);
                        down_read(&mdsc->snap_rwsem);
                        spin_lock(&ci->i_ceph_lock);
                        issued = __ceph_caps_issued(ci, NULL);
                }
        }

        dout("setattr %p issued %s\n", inode, ceph_cap_string(issued));

        if (ia_valid & ATTR_UID) {
                dout("setattr %p uid %d -> %d\n", inode,
                     from_kuid(&init_user_ns, inode->i_uid),
                     from_kuid(&init_user_ns, attr->ia_uid));
                if (issued & CEPH_CAP_AUTH_EXCL) {
                        inode->i_uid = attr->ia_uid;
                        dirtied |= CEPH_CAP_AUTH_EXCL;
                } else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
                           !uid_eq(attr->ia_uid, inode->i_uid)) {
                        req->r_args.setattr.uid = cpu_to_le32(
                                from_kuid(&init_user_ns, attr->ia_uid));
                        mask |= CEPH_SETATTR_UID;
                        release |= CEPH_CAP_AUTH_SHARED;
                }
        }
        if (ia_valid & ATTR_GID) {
                dout("setattr %p gid %d -> %d\n", inode,
                     from_kgid(&init_user_ns, inode->i_gid),
                     from_kgid(&init_user_ns, attr->ia_gid));
                if (issued & CEPH_CAP_AUTH_EXCL) {
                        inode->i_gid = attr->ia_gid;
                        dirtied |= CEPH_CAP_AUTH_EXCL;
                } else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
                           !gid_eq(attr->ia_gid, inode->i_gid)) {
                        req->r_args.setattr.gid = cpu_to_le32(
                                from_kgid(&init_user_ns, attr->ia_gid));
                        mask |= CEPH_SETATTR_GID;
                        release |= CEPH_CAP_AUTH_SHARED;
                }
        }
        if (ia_valid & ATTR_MODE) {
                dout("setattr %p mode 0%o -> 0%o\n", inode, inode->i_mode,
                     attr->ia_mode);
                if (issued & CEPH_CAP_AUTH_EXCL) {
                        inode->i_mode = attr->ia_mode;
                        dirtied |= CEPH_CAP_AUTH_EXCL;
                } else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
                           attr->ia_mode != inode->i_mode) {
                        inode->i_mode = attr->ia_mode;
                        req->r_args.setattr.mode = cpu_to_le32(attr->ia_mode);
                        mask |= CEPH_SETATTR_MODE;
                        release |= CEPH_CAP_AUTH_SHARED;
                }
        }

        if (ia_valid & ATTR_ATIME) {
                dout("setattr %p atime %lld.%ld -> %lld.%ld\n", inode,
                     inode->i_atime.tv_sec, inode->i_atime.tv_nsec,
                     attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec);
                if (issued & CEPH_CAP_FILE_EXCL) {
                        ci->i_time_warp_seq++;
                        inode->i_atime = attr->ia_atime;
                        dirtied |= CEPH_CAP_FILE_EXCL;
                } else if ((issued & CEPH_CAP_FILE_WR) &&
                           timespec64_compare(&inode->i_atime,
                                            &attr->ia_atime) < 0) {
                        inode->i_atime = attr->ia_atime;
                        dirtied |= CEPH_CAP_FILE_WR;
                } else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
                           !timespec64_equal(&inode->i_atime, &attr->ia_atime)) {
                        ceph_encode_timespec64(&req->r_args.setattr.atime,
                                               &attr->ia_atime);
                        mask |= CEPH_SETATTR_ATIME;
                        release |= CEPH_CAP_FILE_SHARED |
                                   CEPH_CAP_FILE_RD | CEPH_CAP_FILE_WR;
                }
        }
        if (ia_valid & ATTR_SIZE) {
                loff_t isize = i_size_read(inode);

                dout("setattr %p size %lld -> %lld\n", inode, isize, attr->ia_size);
                if ((issued & CEPH_CAP_FILE_EXCL) && attr->ia_size > isize) {
                        i_size_write(inode, attr->ia_size);
                        inode->i_blocks = calc_inode_blocks(attr->ia_size);
                        ci->i_reported_size = attr->ia_size;
                        dirtied |= CEPH_CAP_FILE_EXCL;
                        ia_valid |= ATTR_MTIME;
                } else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
                           attr->ia_size != isize) {
                        req->r_args.setattr.size = cpu_to_le64(attr->ia_size);
                        req->r_args.setattr.old_size = cpu_to_le64(isize);
                        mask |= CEPH_SETATTR_SIZE;
                        release |= CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_EXCL |
                                   CEPH_CAP_FILE_RD | CEPH_CAP_FILE_WR;
                }
        }
        if (ia_valid & ATTR_MTIME) {
                dout("setattr %p mtime %lld.%ld -> %lld.%ld\n", inode,
                     inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
                     attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec);
                if (issued & CEPH_CAP_FILE_EXCL) {
                        ci->i_time_warp_seq++;
                        inode->i_mtime = attr->ia_mtime;
                        dirtied |= CEPH_CAP_FILE_EXCL;
                } else if ((issued & CEPH_CAP_FILE_WR) &&
                           timespec64_compare(&inode->i_mtime,
                                            &attr->ia_mtime) < 0) {
                        inode->i_mtime = attr->ia_mtime;
                        dirtied |= CEPH_CAP_FILE_WR;
                } else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
                           !timespec64_equal(&inode->i_mtime, &attr->ia_mtime)) {
                        ceph_encode_timespec64(&req->r_args.setattr.mtime,
                                               &attr->ia_mtime);
                        mask |= CEPH_SETATTR_MTIME;
                        release |= CEPH_CAP_FILE_SHARED |
                                   CEPH_CAP_FILE_RD | CEPH_CAP_FILE_WR;
                }
        }

        /* these do nothing */
        if (ia_valid & ATTR_CTIME) {
                bool only = (ia_valid & (ATTR_SIZE|ATTR_MTIME|ATTR_ATIME|
                                         ATTR_MODE|ATTR_UID|ATTR_GID)) == 0;
                dout("setattr %p ctime %lld.%ld -> %lld.%ld (%s)\n", inode,
                     inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
                     attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec,
                     only ? "ctime only" : "ignored");
                if (only) {
                        /*
                         * if kernel wants to dirty ctime but nothing else,
                         * we need to choose a cap to dirty under, or do
                         * a almost-no-op setattr
                         */
                        if (issued & CEPH_CAP_AUTH_EXCL)
                                dirtied |= CEPH_CAP_AUTH_EXCL;
                        else if (issued & CEPH_CAP_FILE_EXCL)
                                dirtied |= CEPH_CAP_FILE_EXCL;
                        else if (issued & CEPH_CAP_XATTR_EXCL)
                                dirtied |= CEPH_CAP_XATTR_EXCL;
                        else
                                mask |= CEPH_SETATTR_CTIME;
                }
        }
        if (ia_valid & ATTR_FILE)
                dout("setattr %p ATTR_FILE ... hrm!\n", inode);

        if (dirtied) {
                inode_dirty_flags = __ceph_mark_dirty_caps(ci, dirtied,
                                                           &prealloc_cf);
                inode->i_ctime = attr->ia_ctime;
        }

        release &= issued;
        spin_unlock(&ci->i_ceph_lock);
        if (lock_snap_rwsem)
                up_read(&mdsc->snap_rwsem);

        if (inode_dirty_flags)
                __mark_inode_dirty(inode, inode_dirty_flags);


        if (mask) {
                req->r_inode = inode;
                ihold(inode);
                req->r_inode_drop = release;
                req->r_args.setattr.mask = cpu_to_le32(mask);
                req->r_num_caps = 1;
                req->r_stamp = attr->ia_ctime;
                err = ceph_mdsc_do_request(mdsc, NULL, req);
        }
        dout("setattr %p result=%d (%s locally, %d remote)\n", inode, err,
             ceph_cap_string(dirtied), mask);

        ceph_mdsc_put_request(req);
        ceph_free_cap_flush(prealloc_cf);

        if (err >= 0 && (mask & CEPH_SETATTR_SIZE))
                __ceph_do_pending_vmtruncate(inode);

        return err;
}

/*
 * setattr
 */
int ceph_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
                 struct iattr *attr)
{
        struct inode *inode = d_inode(dentry);
        struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
        int err;

        if (ceph_snap(inode) != CEPH_NOSNAP)
                return -EROFS;

        err = setattr_prepare(&init_user_ns, dentry, attr);
        if (err != 0)
                return err;

        if ((attr->ia_valid & ATTR_SIZE) &&
            attr->ia_size > max(i_size_read(inode), fsc->max_file_size))
                return -EFBIG;

        if ((attr->ia_valid & ATTR_SIZE) &&
            ceph_quota_is_max_bytes_exceeded(inode, attr->ia_size))
                return -EDQUOT;

        err = __ceph_setattr(inode, attr);

        if (err >= 0 && (attr->ia_valid & ATTR_MODE))
                err = posix_acl_chmod(&init_user_ns, inode, attr->ia_mode);

        return err;
}

/*
 * Verify that we have a lease on the given mask.  If not,
 * do a getattr against an mds.
 */
int __ceph_do_getattr(struct inode *inode, struct page *locked_page,
                      int mask, bool force)
{
        struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
        struct ceph_mds_client *mdsc = fsc->mdsc;
        struct ceph_mds_request *req;
        int mode;
        int err;

        if (ceph_snap(inode) == CEPH_SNAPDIR) {
                dout("do_getattr inode %p SNAPDIR\n", inode);
                return 0;
        }

        dout("do_getattr inode %p mask %s mode 0%o\n",
             inode, ceph_cap_string(mask), inode->i_mode);
        if (!force && ceph_caps_issued_mask_metric(ceph_inode(inode), mask, 1))
                        return 0;

        mode = (mask & CEPH_STAT_RSTAT) ? USE_AUTH_MDS : USE_ANY_MDS;
        req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, mode);
        if (IS_ERR(req))
                return PTR_ERR(req);
        req->r_inode = inode;
        ihold(inode);
        req->r_num_caps = 1;
        req->r_args.getattr.mask = cpu_to_le32(mask);
        req->r_locked_page = locked_page;
        err = ceph_mdsc_do_request(mdsc, NULL, req);
        if (locked_page && err == 0) {
                u64 inline_version = req->r_reply_info.targeti.inline_version;
                if (inline_version == 0) {
                        /* the reply is supposed to contain inline data */
                        err = -EINVAL;
                } else if (inline_version == CEPH_INLINE_NONE) {
                        err = -ENODATA;
                } else {
                        err = req->r_reply_info.targeti.inline_len;
                }
        }
        ceph_mdsc_put_request(req);
        dout("do_getattr result=%d\n", err);
        return err;
}


/*
 * Check inode permissions.  We verify we have a valid value for
 * the AUTH cap, then call the generic handler.
 */
int ceph_permission(struct user_namespace *mnt_userns, struct inode *inode,
                    int mask)
{
        int err;

        if (mask & MAY_NOT_BLOCK)
                return -ECHILD;

        err = ceph_do_getattr(inode, CEPH_CAP_AUTH_SHARED, false);

        if (!err)
                err = generic_permission(&init_user_ns, inode, mask);
        return err;
}

/* Craft a mask of needed caps given a set of requested statx attrs. */
static int statx_to_caps(u32 want, umode_t mode)
{
        int mask = 0;

        if (want & (STATX_MODE|STATX_UID|STATX_GID|STATX_CTIME|STATX_BTIME))
                mask |= CEPH_CAP_AUTH_SHARED;

        if (want & (STATX_NLINK|STATX_CTIME)) {
                /*
                 * The link count for directories depends on inode->i_subdirs,
                 * and that is only updated when Fs caps are held.
                 */
                if (S_ISDIR(mode))
                        mask |= CEPH_CAP_FILE_SHARED;
                else
                        mask |= CEPH_CAP_LINK_SHARED;
        }

        if (want & (STATX_ATIME|STATX_MTIME|STATX_CTIME|STATX_SIZE|
                    STATX_BLOCKS))
                mask |= CEPH_CAP_FILE_SHARED;

        if (want & (STATX_CTIME))
                mask |= CEPH_CAP_XATTR_SHARED;

        return mask;
}

/*
 * Get all the attributes. If we have sufficient caps for the requested attrs,
 * then we can avoid talking to the MDS at all.
 */
int ceph_getattr(struct user_namespace *mnt_userns, const struct path *path,
                 struct kstat *stat, u32 request_mask, unsigned int flags)
{
        struct inode *inode = d_inode(path->dentry);
        struct ceph_inode_info *ci = ceph_inode(inode);
        u32 valid_mask = STATX_BASIC_STATS;
        int err = 0;

        /* Skip the getattr altogether if we're asked not to sync */
        if (!(flags & AT_STATX_DONT_SYNC)) {
                err = ceph_do_getattr(inode,
                                statx_to_caps(request_mask, inode->i_mode),
                                flags & AT_STATX_FORCE_SYNC);
                if (err)
                        return err;
        }

        generic_fillattr(&init_user_ns, inode, stat);
        stat->ino = ceph_present_inode(inode);

        /*
         * btime on newly-allocated inodes is 0, so if this is still set to
         * that, then assume that it's not valid.
         */
        if (ci->i_btime.tv_sec || ci->i_btime.tv_nsec) {
                stat->btime = ci->i_btime;
                valid_mask |= STATX_BTIME;
        }

        if (ceph_snap(inode) == CEPH_NOSNAP)
                stat->dev = inode->i_sb->s_dev;
        else
                stat->dev = ci->i_snapid_map ? ci->i_snapid_map->dev : 0;

        if (S_ISDIR(inode->i_mode)) {
                if (ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb),
                                        RBYTES))
                        stat->size = ci->i_rbytes;
                else
                        stat->size = ci->i_files + ci->i_subdirs;
                stat->blocks = 0;
                stat->blksize = 65536;
                /*
                 * Some applications rely on the number of st_nlink
                 * value on directories to be either 0 (if unlinked)
                 * or 2 + number of subdirectories.
                 */
                if (stat->nlink == 1)
                        /* '.' + '..' + subdirs */
                        stat->nlink = 1 + 1 + ci->i_subdirs;
        }

        stat->result_mask = request_mask & valid_mask;
        return err;
}