ceph: rework dcache readdir
authorYan, Zheng <zyan@redhat.com>
Tue, 16 Jun 2015 12:48:56 +0000 (20:48 +0800)
committerIlya Dryomov <idryomov@gmail.com>
Thu, 25 Jun 2015 08:49:32 +0000 (11:49 +0300)
Previously our dcache readdir code relies on that child dentries in
directory dentry's d_subdir list are sorted by dentry's offset in
descending order. When adding dentries to the dcache, if a dentry
already exists, our readdir code moves it to head of directory
dentry's d_subdir list. This design relies on dcache internals.
Al Viro suggests using ncpfs's approach: keeping array of pointers
to dentries in page cache of directory inode. the validity of those
pointers are presented by directory inode's complete and ordered
flags. When a dentry gets pruned, we clear directory inode's complete
flag in the d_prune() callback. Before moving a dentry to other
directory, we clear the ordered flag for both old and new directory.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
fs/ceph/caps.c
fs/ceph/dir.c
fs/ceph/file.c
fs/ceph/inode.c
fs/ceph/mds_client.h
fs/ceph/super.h

index dd7b20adf1d400409d86941515438cce53d634d1..dc10c9dd36c1a2ac6264ed21d3248e5f62f1e330 100644 (file)
@@ -833,7 +833,9 @@ int __ceph_caps_used(struct ceph_inode_info *ci)
                used |= CEPH_CAP_PIN;
        if (ci->i_rd_ref)
                used |= CEPH_CAP_FILE_RD;
-       if (ci->i_rdcache_ref || ci->vfs_inode.i_data.nrpages)
+       if (ci->i_rdcache_ref ||
+           (!S_ISDIR(ci->vfs_inode.i_mode) && /* ignore readdir cache */
+            ci->vfs_inode.i_data.nrpages))
                used |= CEPH_CAP_FILE_CACHE;
        if (ci->i_wr_ref)
                used |= CEPH_CAP_FILE_WR;
@@ -1651,9 +1653,10 @@ retry_locked:
         * If we fail, it's because pages are locked.... try again later.
         */
        if ((!is_delayed || mdsc->stopping) &&
-           ci->i_wrbuffer_ref == 0 &&               /* no dirty pages... */
-           inode->i_data.nrpages &&                 /* have cached pages */
-           (file_wanted == 0 ||                     /* no open files */
+           !S_ISDIR(inode->i_mode) &&          /* ignore readdir cache */
+           ci->i_wrbuffer_ref == 0 &&          /* no dirty pages... */
+           inode->i_data.nrpages &&            /* have cached pages */
+           (file_wanted == 0 ||                /* no open files */
             (revoking & (CEPH_CAP_FILE_CACHE|
                          CEPH_CAP_FILE_LAZYIO))) && /*  or revoking cache */
            !tried_invalidate) {
@@ -2805,7 +2808,8 @@ static void handle_cap_grant(struct ceph_mds_client *mdsc,
         * try to invalidate (once).  (If there are dirty buffers, we
         * will invalidate _after_ writeback.)
         */
-       if (((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
+       if (!S_ISDIR(inode->i_mode) && /* don't invalidate readdir cache */
+           ((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
            (newcaps & CEPH_CAP_FILE_LAZYIO) == 0 &&
            !ci->i_wrbuffer_ref) {
                if (try_nonblocking_invalidate(inode)) {
index b99f2ff8189db8255f90c6efbf17b3b8e5c32669..9314b4ea2375145647aa16446a1f33ae2c8106b2 100644 (file)
@@ -106,6 +106,27 @@ static int fpos_cmp(loff_t l, loff_t r)
        return (int)(fpos_off(l) - fpos_off(r));
 }
 
+/*
+ * make note of the last dentry we read, so we can
+ * continue at the same lexicographical point,
+ * regardless of what dir changes take place on the
+ * server.
+ */
+static int note_last_dentry(struct ceph_file_info *fi, const char *name,
+                           int len, unsigned next_offset)
+{
+       char *buf = kmalloc(len+1, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+       kfree(fi->last_name);
+       fi->last_name = buf;
+       memcpy(fi->last_name, name, len);
+       fi->last_name[len] = 0;
+       fi->next_offset = next_offset;
+       dout("note_last_dentry '%s'\n", fi->last_name);
+       return 0;
+}
+
 /*
  * When possible, we try to satisfy a readdir by peeking at the
  * dcache.  We make this work by carefully ordering dentries on
@@ -123,123 +144,113 @@ static int __dcache_readdir(struct file *file,  struct dir_context *ctx,
        struct ceph_file_info *fi = file->private_data;
        struct dentry *parent = file->f_path.dentry;
        struct inode *dir = d_inode(parent);
-       struct list_head *p;
-       struct dentry *dentry, *last;
+       struct dentry *dentry, *last = NULL;
        struct ceph_dentry_info *di;
+       unsigned nsize = PAGE_CACHE_SIZE / sizeof(struct dentry *);
        int err = 0;
+       loff_t ptr_pos = 0;
+       struct ceph_readdir_cache_control cache_ctl = {};
 
-       /* claim ref on last dentry we returned */
-       last = fi->dentry;
-       fi->dentry = NULL;
-
-       dout("__dcache_readdir %p v%u at %llu (last %p)\n",
-            dir, shared_gen, ctx->pos, last);
-
-       spin_lock(&parent->d_lock);
+       dout("__dcache_readdir %p v%u at %llu\n", dir, shared_gen, ctx->pos);
 
-       /* start at beginning? */
-       if (ctx->pos == 2 || last == NULL ||
-           fpos_cmp(ctx->pos, ceph_dentry(last)->offset) < 0) {
-               if (list_empty(&parent->d_subdirs))
-                       goto out_unlock;
-               p = parent->d_subdirs.prev;
-               dout(" initial p %p/%p\n", p->prev, p->next);
-       } else {
-               p = last->d_child.prev;
+       /* we can calculate cache index for the first dirfrag */
+       if (ceph_frag_is_leftmost(fpos_frag(ctx->pos))) {
+               cache_ctl.index = fpos_off(ctx->pos) - 2;
+               BUG_ON(cache_ctl.index < 0);
+               ptr_pos = cache_ctl.index * sizeof(struct dentry *);
        }
 
-more:
-       dentry = list_entry(p, struct dentry, d_child);
-       di = ceph_dentry(dentry);
-       while (1) {
-               dout(" p %p/%p %s d_subdirs %p/%p\n", p->prev, p->next,
-                    d_unhashed(dentry) ? "!hashed" : "hashed",
-                    parent->d_subdirs.prev, parent->d_subdirs.next);
-               if (p == &parent->d_subdirs) {
+       while (true) {
+               pgoff_t pgoff;
+               bool emit_dentry;
+
+               if (ptr_pos >= i_size_read(dir)) {
                        fi->flags |= CEPH_F_ATEND;
-                       goto out_unlock;
+                       err = 0;
+                       break;
                }
-               spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+
+               err = -EAGAIN;
+               pgoff = ptr_pos >> PAGE_CACHE_SHIFT;
+               if (!cache_ctl.page || pgoff != page_index(cache_ctl.page)) {
+                       ceph_readdir_cache_release(&cache_ctl);
+                       cache_ctl.page = find_lock_page(&dir->i_data, pgoff);
+                       if (!cache_ctl.page) {
+                               dout(" page %lu not found\n", pgoff);
+                               break;
+                       }
+                       /* reading/filling the cache are serialized by
+                        * i_mutex, no need to use page lock */
+                       unlock_page(cache_ctl.page);
+                       cache_ctl.dentries = kmap(cache_ctl.page);
+               }
+
+               rcu_read_lock();
+               spin_lock(&parent->d_lock);
+               /* check i_size again here, because empty directory can be
+                * marked as complete while not holding the i_mutex. */
+               if (ceph_dir_is_complete_ordered(dir) &&
+                   ptr_pos < i_size_read(dir))
+                       dentry = cache_ctl.dentries[cache_ctl.index % nsize];
+               else
+                       dentry = NULL;
+               spin_unlock(&parent->d_lock);
+               if (dentry && !lockref_get_not_dead(&dentry->d_lockref))
+                       dentry = NULL;
+               rcu_read_unlock();
+               if (!dentry)
+                       break;
+
+               emit_dentry = false;
+               di = ceph_dentry(dentry);
+               spin_lock(&dentry->d_lock);
                if (di->lease_shared_gen == shared_gen &&
-                   !d_unhashed(dentry) && d_really_is_positive(dentry) &&
+                   d_really_is_positive(dentry) &&
                    ceph_snap(d_inode(dentry)) != CEPH_SNAPDIR &&
                    ceph_ino(d_inode(dentry)) != CEPH_INO_CEPH &&
-                   fpos_cmp(ctx->pos, di->offset) <= 0)
-                       break;
-               dout(" skipping %p %pd at %llu (%llu)%s%s\n", dentry,
-                    dentry, di->offset,
-                    ctx->pos, d_unhashed(dentry) ? " unhashed" : "",
-                    !d_inode(dentry) ? " null" : "");
+                   fpos_cmp(ctx->pos, di->offset) <= 0) {
+                       emit_dentry = true;
+               }
                spin_unlock(&dentry->d_lock);
-               p = p->prev;
-               dentry = list_entry(p, struct dentry, d_child);
-               di = ceph_dentry(dentry);
-       }
-
-       dget_dlock(dentry);
-       spin_unlock(&dentry->d_lock);
-       spin_unlock(&parent->d_lock);
 
-       /* make sure a dentry wasn't dropped while we didn't have parent lock */
-       if (!ceph_dir_is_complete_ordered(dir)) {
-               dout(" lost dir complete on %p; falling back to mds\n", dir);
-               dput(dentry);
-               err = -EAGAIN;
-               goto out;
-       }
+               if (emit_dentry) {
+                       dout(" %llu (%llu) dentry %p %pd %p\n", di->offset, ctx->pos,
+                            dentry, dentry, d_inode(dentry));
+                       ctx->pos = di->offset;
+                       if (!dir_emit(ctx, dentry->d_name.name,
+                                     dentry->d_name.len,
+                                     ceph_translate_ino(dentry->d_sb,
+                                                        d_inode(dentry)->i_ino),
+                                     d_inode(dentry)->i_mode >> 12)) {
+                               dput(dentry);
+                               err = 0;
+                               break;
+                       }
+                       ctx->pos++;
 
-       dout(" %llu (%llu) dentry %p %pd %p\n", di->offset, ctx->pos,
-            dentry, dentry, d_inode(dentry));
-       if (!dir_emit(ctx, dentry->d_name.name,
-                     dentry->d_name.len,
-                     ceph_translate_ino(dentry->d_sb, d_inode(dentry)->i_ino),
-                     d_inode(dentry)->i_mode >> 12)) {
-               if (last) {
-                       /* remember our position */
-                       fi->dentry = last;
-                       fi->next_offset = fpos_off(di->offset);
+                       if (last)
+                               dput(last);
+                       last = dentry;
+               } else {
+                       dput(dentry);
                }
-               dput(dentry);
-               return 0;
-       }
-
-       ctx->pos = di->offset + 1;
-
-       if (last)
-               dput(last);
-       last = dentry;
-
-       spin_lock(&parent->d_lock);
-       p = p->prev;    /* advance to next dentry */
-       goto more;
 
-out_unlock:
-       spin_unlock(&parent->d_lock);
-out:
-       if (last)
+               cache_ctl.index++;
+               ptr_pos += sizeof(struct dentry *);
+       }
+       ceph_readdir_cache_release(&cache_ctl);
+       if (last) {
+               int ret;
+               di = ceph_dentry(last);
+               ret = note_last_dentry(fi, last->d_name.name, last->d_name.len,
+                                      fpos_off(di->offset) + 1);
+               if (ret < 0)
+                       err = ret;
                dput(last);
+       }
        return err;
 }
 
-/*
- * make note of the last dentry we read, so we can
- * continue at the same lexicographical point,
- * regardless of what dir changes take place on the
- * server.
- */
-static int note_last_dentry(struct ceph_file_info *fi, const char *name,
-                           int len)
-{
-       kfree(fi->last_name);
-       fi->last_name = kmalloc(len+1, GFP_KERNEL);
-       if (!fi->last_name)
-               return -ENOMEM;
-       memcpy(fi->last_name, name, len);
-       fi->last_name[len] = 0;
-       dout("note_last_dentry '%s'\n", fi->last_name);
-       return 0;
-}
-
 static int ceph_readdir(struct file *file, struct dir_context *ctx)
 {
        struct ceph_file_info *fi = file->private_data;
@@ -280,8 +291,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 
        /* can we use the dcache? */
        spin_lock(&ci->i_ceph_lock);
-       if ((ctx->pos == 2 || fi->dentry) &&
-           ceph_test_mount_opt(fsc, DCACHE) &&
+       if (ceph_test_mount_opt(fsc, DCACHE) &&
            !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
            ceph_snap(inode) != CEPH_SNAPDIR &&
            __ceph_dir_is_complete_ordered(ci) &&
@@ -296,24 +306,8 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
        } else {
                spin_unlock(&ci->i_ceph_lock);
        }
-       if (fi->dentry) {
-               err = note_last_dentry(fi, fi->dentry->d_name.name,
-                                      fi->dentry->d_name.len);
-               if (err)
-                       return err;
-               dput(fi->dentry);
-               fi->dentry = NULL;
-       }
 
        /* proceed with a normal readdir */
-
-       if (ctx->pos == 2) {
-               /* note dir version at start of readdir so we can tell
-                * if any dentries get dropped */
-               fi->dir_release_count = atomic_read(&ci->i_release_count);
-               fi->dir_ordered_count = ci->i_ordered_count;
-       }
-
 more:
        /* do we have the correct frag content buffered? */
        if (fi->frag != frag || fi->last_readdir == NULL) {
@@ -348,6 +342,9 @@ more:
                                return -ENOMEM;
                        }
                }
+               req->r_dir_release_cnt = fi->dir_release_count;
+               req->r_dir_ordered_cnt = fi->dir_ordered_count;
+               req->r_readdir_cache_idx = fi->readdir_cache_idx;
                req->r_readdir_offset = fi->next_offset;
                req->r_args.readdir.frag = cpu_to_le32(frag);
 
@@ -364,26 +361,38 @@ more:
                     (int)req->r_reply_info.dir_end,
                     (int)req->r_reply_info.dir_complete);
 
-               if (!req->r_did_prepopulate) {
-                       dout("readdir !did_prepopulate");
-                       /* preclude from marking dir complete */
-                       fi->dir_release_count--;
-               }
 
                /* note next offset and last dentry name */
                rinfo = &req->r_reply_info;
                if (le32_to_cpu(rinfo->dir_dir->frag) != frag) {
                        frag = le32_to_cpu(rinfo->dir_dir->frag);
-                       if (ceph_frag_is_leftmost(frag))
-                               fi->next_offset = 2;
-                       else
-                               fi->next_offset = 0;
-                       off = fi->next_offset;
+                       off = req->r_readdir_offset;
+                       fi->next_offset = off;
                }
+
                fi->frag = frag;
                fi->offset = fi->next_offset;
                fi->last_readdir = req;
 
+               if (req->r_did_prepopulate) {
+                       fi->readdir_cache_idx = req->r_readdir_cache_idx;
+                       if (fi->readdir_cache_idx < 0) {
+                               /* preclude from marking dir ordered */
+                               fi->dir_ordered_count = 0;
+                       } else if (ceph_frag_is_leftmost(frag) && off == 2) {
+                               /* note dir version at start of readdir so
+                                * we can tell if any dentries get dropped */
+                               fi->dir_release_count = req->r_dir_release_cnt;
+                               fi->dir_ordered_count = req->r_dir_ordered_cnt;
+                       }
+               } else {
+                       dout("readdir !did_prepopulate");
+                       /* disable readdir cache */
+                       fi->readdir_cache_idx = -1;
+                       /* preclude from marking dir complete */
+                       fi->dir_release_count = 0;
+               }
+
                if (req->r_reply_info.dir_end) {
                        kfree(fi->last_name);
                        fi->last_name = NULL;
@@ -394,10 +403,10 @@ more:
                } else {
                        err = note_last_dentry(fi,
                                       rinfo->dir_dname[rinfo->dir_nr-1],
-                                      rinfo->dir_dname_len[rinfo->dir_nr-1]);
+                                      rinfo->dir_dname_len[rinfo->dir_nr-1],
+                                      fi->next_offset + rinfo->dir_nr);
                        if (err)
                                return err;
-                       fi->next_offset += rinfo->dir_nr;
                }
        }
 
@@ -453,16 +462,22 @@ more:
         * were released during the whole readdir, and we should have
         * the complete dir contents in our cache.
         */
-       spin_lock(&ci->i_ceph_lock);
-       if (atomic_read(&ci->i_release_count) == fi->dir_release_count) {
-               if (ci->i_ordered_count == fi->dir_ordered_count)
+       if (atomic64_read(&ci->i_release_count) == fi->dir_release_count) {
+               spin_lock(&ci->i_ceph_lock);
+               if (fi->dir_ordered_count == atomic64_read(&ci->i_ordered_count)) {
                        dout(" marking %p complete and ordered\n", inode);
-               else
+                       /* use i_size to track number of entries in
+                        * readdir cache */
+                       BUG_ON(fi->readdir_cache_idx < 0);
+                       i_size_write(inode, fi->readdir_cache_idx *
+                                    sizeof(struct dentry*));
+               } else {
                        dout(" marking %p complete\n", inode);
+               }
                __ceph_dir_set_complete(ci, fi->dir_release_count,
                                        fi->dir_ordered_count);
+               spin_unlock(&ci->i_ceph_lock);
        }
-       spin_unlock(&ci->i_ceph_lock);
 
        dout("readdir %p file %p done.\n", inode, file);
        return 0;
@@ -476,14 +491,12 @@ static void reset_readdir(struct ceph_file_info *fi, unsigned frag)
        }
        kfree(fi->last_name);
        fi->last_name = NULL;
+       fi->dir_release_count = 0;
+       fi->readdir_cache_idx = -1;
        if (ceph_frag_is_leftmost(frag))
                fi->next_offset = 2;  /* compensate for . and .. */
        else
                fi->next_offset = 0;
-       if (fi->dentry) {
-               dput(fi->dentry);
-               fi->dentry = NULL;
-       }
        fi->flags &= ~CEPH_F_ATEND;
 }
 
@@ -497,13 +510,12 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
        mutex_lock(&inode->i_mutex);
        retval = -EINVAL;
        switch (whence) {
-       case SEEK_END:
-               offset += inode->i_size + 2;   /* FIXME */
-               break;
        case SEEK_CUR:
                offset += file->f_pos;
        case SEEK_SET:
                break;
+       case SEEK_END:
+               retval = -EOPNOTSUPP;
        default:
                goto out;
        }
@@ -516,20 +528,18 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
                }
                retval = offset;
 
-               /*
-                * discard buffered readdir content on seekdir(0), or
-                * seek to new frag, or seek prior to current chunk.
-                */
                if (offset == 0 ||
                    fpos_frag(offset) != fi->frag ||
                    fpos_off(offset) < fi->offset) {
+                       /* discard buffered readdir content on seekdir(0), or
+                        * seek to new frag, or seek prior to current chunk */
                        dout("dir_llseek dropping %p content\n", file);
                        reset_readdir(fi, fpos_frag(offset));
+               } else if (fpos_cmp(offset, old_offset) > 0) {
+                       /* reset dir_release_count if we did a forward seek */
+                       fi->dir_release_count = 0;
+                       fi->readdir_cache_idx = -1;
                }
-
-               /* bump dir_release_count if we did a forward seek */
-               if (fpos_cmp(offset, old_offset) > 0)
-                       fi->dir_release_count--;
        }
 out:
        mutex_unlock(&inode->i_mutex);
@@ -985,16 +995,15 @@ static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
                 * to do it here.
                 */
 
+               /* d_move screws up sibling dentries' offsets */
+               ceph_dir_clear_complete(old_dir);
+               ceph_dir_clear_complete(new_dir);
+
                d_move(old_dentry, new_dentry);
 
                /* ensure target dentry is invalidated, despite
                   rehashing bug in vfs_rename_dir */
                ceph_invalidate_dentry_lease(new_dentry);
-
-               /* d_move screws up sibling dentries' offsets */
-               ceph_dir_clear_complete(old_dir);
-               ceph_dir_clear_complete(new_dir);
-
        }
        ceph_mdsc_put_request(req);
        return err;
index 424b5b540207f74822c60214d2150f307752eebe..faf92095e105650617d8e465e898f8d22a803d60 100644 (file)
@@ -96,6 +96,7 @@ static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
                }
                cf->fmode = fmode;
                cf->next_offset = 2;
+               cf->readdir_cache_idx = -1;
                file->private_data = cf;
                BUG_ON(inode->i_fop->release != ceph_release);
                break;
@@ -324,7 +325,6 @@ int ceph_release(struct inode *inode, struct file *file)
                ceph_mdsc_put_request(cf->last_readdir);
        kfree(cf->last_name);
        kfree(cf->dir_info);
-       dput(cf->dentry);
        kmem_cache_free(ceph_file_cachep, cf);
 
        /* wake up anyone waiting for caps on this inode */
index e86d1a4efc4603f62704bb7eb8d91593b0b4e2f5..2a6d93befbaea54dde7678e2d63ffca113aba3d3 100644 (file)
@@ -390,9 +390,10 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
        ci->i_inline_version = 0;
        ci->i_time_warp_seq = 0;
        ci->i_ceph_flags = 0;
-       ci->i_ordered_count = 0;
-       atomic_set(&ci->i_release_count, 1);
-       atomic_set(&ci->i_complete_count, 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;
 
        memset(&ci->i_dir_layout, 0, sizeof(ci->i_dir_layout));
@@ -860,9 +861,10 @@ static int fill_inode(struct inode *inode, struct page *locked_page,
                            (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,
-                                       atomic_read(&ci->i_release_count),
-                                       ci->i_ordered_count);
+                                       atomic64_read(&ci->i_release_count),
+                                       atomic64_read(&ci->i_ordered_count));
                        }
 
                        wake = true;
@@ -1214,6 +1216,10 @@ retry_lookup:
                        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,
@@ -1224,10 +1230,6 @@ retry_lookup:
                           rehashing bug in vfs_rename_dir */
                        ceph_invalidate_dentry_lease(dn);
 
-                       /* d_move screws up sibling dentries' offsets */
-                       ceph_dir_clear_ordered(dir);
-                       ceph_dir_clear_ordered(olddir);
-
                        dout("dn %p gets new offset %lld\n", req->r_old_dentry,
                             ceph_dentry(req->r_old_dentry)->offset);
 
@@ -1335,6 +1337,49 @@ static int readdir_prepopulate_inodes_only(struct ceph_mds_request *req,
        return err;
 }
 
+void ceph_readdir_cache_release(struct ceph_readdir_cache_control *ctl)
+{
+       if (ctl->page) {
+               kunmap(ctl->page);
+               page_cache_release(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_CACHE_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);
+               ctl->page  = grab_cache_page(&dir->i_data, pgoff);
+               if (!ctl->page) {
+                       ctl->index = -1;
+                       return -ENOMEM;
+               }
+               /* 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 (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)
 {
@@ -1347,8 +1392,11 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
        struct inode *snapdir = NULL;
        struct ceph_mds_request_head *rhead = req->r_request->front.iov_base;
        struct ceph_dentry_info *di;
-       u64 r_readdir_offset = req->r_readdir_offset;
        u32 frag = le32_to_cpu(rhead->args.readdir.frag);
+       struct ceph_readdir_cache_control cache_ctl = {};
+
+       if (req->r_aborted)
+               return readdir_prepopulate_inodes_only(req, session);
 
        if (rinfo->dir_dir &&
            le32_to_cpu(rinfo->dir_dir->frag) != frag) {
@@ -1356,14 +1404,11 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
                     frag, le32_to_cpu(rinfo->dir_dir->frag));
                frag = le32_to_cpu(rinfo->dir_dir->frag);
                if (ceph_frag_is_leftmost(frag))
-                       r_readdir_offset = 2;
+                       req->r_readdir_offset = 2;
                else
-                       r_readdir_offset = 0;
+                       req->r_readdir_offset = 0;
        }
 
-       if (req->r_aborted)
-               return readdir_prepopulate_inodes_only(req, session);
-
        if (le32_to_cpu(rinfo->head->op) == CEPH_MDS_OP_LSSNAP) {
                snapdir = ceph_get_snapdir(d_inode(parent));
                parent = d_find_alias(snapdir);
@@ -1376,6 +1421,17 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
                        ceph_fill_dirfrag(d_inode(parent), rinfo->dir_dir);
        }
 
+       if (ceph_frag_is_leftmost(frag) && req->r_readdir_offset == 2) {
+               /* note dir version at start of readdir so we can tell
+                * if any dentries get dropped */
+               struct ceph_inode_info *ci = ceph_inode(d_inode(parent));
+               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;
+
        /* FIXME: release caps/leases if error occurs */
        for (i = 0; i < rinfo->dir_nr; i++) {
                struct ceph_vino vino;
@@ -1415,13 +1471,6 @@ retry_lookup:
                        d_delete(dn);
                        dput(dn);
                        goto retry_lookup;
-               } else {
-                       /* reorder parent's d_subdirs */
-                       spin_lock(&parent->d_lock);
-                       spin_lock_nested(&dn->d_lock, DENTRY_D_LOCK_NESTED);
-                       list_move(&dn->d_child, &parent->d_subdirs);
-                       spin_unlock(&dn->d_lock);
-                       spin_unlock(&parent->d_lock);
                }
 
                /* inode */
@@ -1438,13 +1487,15 @@ retry_lookup:
                        }
                }
 
-               if (fill_inode(in, NULL, &rinfo->dir_in[i], NULL, session,
-                              req->r_request_started, -1,
-                              &req->r_caps_reservation) < 0) {
+               ret = fill_inode(in, NULL, &rinfo->dir_in[i], NULL, session,
+                                req->r_request_started, -1,
+                                &req->r_caps_reservation);
+               if (ret < 0) {
                        pr_err("fill_inode badness on %p\n", in);
                        if (d_really_is_negative(dn))
                                iput(in);
                        d_drop(dn);
+                       err = ret;
                        goto next_item;
                }
 
@@ -1460,19 +1511,28 @@ retry_lookup:
                }
 
                di = dn->d_fsdata;
-               di->offset = ceph_make_fpos(frag, i + r_readdir_offset);
+               di->offset = ceph_make_fpos(frag, i + req->r_readdir_offset);
 
                update_dentry_lease(dn, rinfo->dir_dlease[i],
                                    req->r_session,
                                    req->r_request_started);
+
+               if (err == 0 && cache_ctl.index >= 0) {
+                       ret = fill_readdir_cache(d_inode(parent), dn,
+                                                &cache_ctl, req);
+                       if (ret < 0)
+                               err = ret;
+               }
 next_item:
                if (dn)
                        dput(dn);
        }
-       if (err == 0)
-               req->r_did_prepopulate = true;
-
 out:
+       if (err == 0) {
+               req->r_did_prepopulate = true;
+               req->r_readdir_cache_idx = cache_ctl.index;
+       }
+       ceph_readdir_cache_release(&cache_ctl);
        if (snapdir) {
                iput(snapdir);
                dput(parent);
index 470be4eb25f3fc4d93e5da89020a04c062525de2..762757e6cebf95fff324894d1650b8271210acdd 100644 (file)
@@ -253,6 +253,9 @@ struct ceph_mds_request {
        bool              r_got_unsafe, r_got_safe, r_got_result;
 
        bool              r_did_prepopulate;
+       long long         r_dir_release_cnt;
+       long long         r_dir_ordered_cnt;
+       int               r_readdir_cache_idx;
        u32               r_readdir_offset;
 
        struct ceph_cap_reservation r_caps_reservation;
index 4415e977d72b435573697bc9ce46d4288883e596..860cc016e70d4ff463c1f7845fc648eaf58269c4 100644 (file)
@@ -282,9 +282,9 @@ struct ceph_inode_info {
        u32 i_time_warp_seq;
 
        unsigned i_ceph_flags;
-       int i_ordered_count;
-       atomic_t i_release_count;
-       atomic_t i_complete_count;
+       atomic64_t i_release_count;
+       atomic64_t i_ordered_count;
+       atomic64_t i_complete_seq[2];
 
        struct ceph_dir_layout i_dir_layout;
        struct ceph_file_layout i_layout;
@@ -471,30 +471,36 @@ static inline struct inode *ceph_find_inode(struct super_block *sb,
 
 
 static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
-                                          int release_count, int ordered_count)
+                                          long long release_count,
+                                          long long ordered_count)
 {
-       atomic_set(&ci->i_complete_count, release_count);
-       if (ci->i_ordered_count == ordered_count)
-               ci->i_ceph_flags |= CEPH_I_DIR_ORDERED;
-       else
-               ci->i_ceph_flags &= ~CEPH_I_DIR_ORDERED;
+       smp_mb__before_atomic();
+       atomic64_set(&ci->i_complete_seq[0], release_count);
+       atomic64_set(&ci->i_complete_seq[1], ordered_count);
 }
 
 static inline void __ceph_dir_clear_complete(struct ceph_inode_info *ci)
 {
-       atomic_inc(&ci->i_release_count);
+       atomic64_inc(&ci->i_release_count);
+}
+
+static inline void __ceph_dir_clear_ordered(struct ceph_inode_info *ci)
+{
+       atomic64_inc(&ci->i_ordered_count);
 }
 
 static inline bool __ceph_dir_is_complete(struct ceph_inode_info *ci)
 {
-       return atomic_read(&ci->i_complete_count) ==
-               atomic_read(&ci->i_release_count);
+       return atomic64_read(&ci->i_complete_seq[0]) ==
+               atomic64_read(&ci->i_release_count);
 }
 
 static inline bool __ceph_dir_is_complete_ordered(struct ceph_inode_info *ci)
 {
-       return __ceph_dir_is_complete(ci) &&
-               (ci->i_ceph_flags & CEPH_I_DIR_ORDERED);
+       return  atomic64_read(&ci->i_complete_seq[0]) ==
+               atomic64_read(&ci->i_release_count) &&
+               atomic64_read(&ci->i_complete_seq[1]) ==
+               atomic64_read(&ci->i_ordered_count);
 }
 
 static inline void ceph_dir_clear_complete(struct inode *inode)
@@ -504,20 +510,13 @@ static inline void ceph_dir_clear_complete(struct inode *inode)
 
 static inline void ceph_dir_clear_ordered(struct inode *inode)
 {
-       struct ceph_inode_info *ci = ceph_inode(inode);
-       spin_lock(&ci->i_ceph_lock);
-       ci->i_ordered_count++;
-       ci->i_ceph_flags &= ~CEPH_I_DIR_ORDERED;
-       spin_unlock(&ci->i_ceph_lock);
+       __ceph_dir_clear_ordered(ceph_inode(inode));
 }
 
 static inline bool ceph_dir_is_complete_ordered(struct inode *inode)
 {
-       struct ceph_inode_info *ci = ceph_inode(inode);
-       bool ret;
-       spin_lock(&ci->i_ceph_lock);
-       ret = __ceph_dir_is_complete_ordered(ci);
-       spin_unlock(&ci->i_ceph_lock);
+       bool ret = __ceph_dir_is_complete_ordered(ceph_inode(inode));
+       smp_rmb();
        return ret;
 }
 
@@ -636,16 +635,20 @@ struct ceph_file_info {
        unsigned offset;       /* offset of last chunk, adjusted for . and .. */
        unsigned next_offset;  /* offset of next chunk (last_name's + 1) */
        char *last_name;       /* last entry in previous chunk */
-       struct dentry *dentry; /* next dentry (for dcache readdir) */
-       int dir_release_count;
-       int dir_ordered_count;
+       long long dir_release_count;
+       long long dir_ordered_count;
+       int readdir_cache_idx;
 
        /* used for -o dirstat read() on directory thing */
        char *dir_info;
        int dir_info_len;
 };
 
-
+struct ceph_readdir_cache_control {
+       struct page  *page;
+       struct dentry **dentries;
+       int index;
+};
 
 /*
  * A "snap realm" describes a subset of the file hierarchy sharing
@@ -944,6 +947,7 @@ extern void ceph_dentry_lru_del(struct dentry *dn);
 extern void ceph_invalidate_dentry_lease(struct dentry *dentry);
 extern unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn);
 extern struct inode *ceph_get_dentry_parent_inode(struct dentry *dentry);
+extern void ceph_readdir_cache_release(struct ceph_readdir_cache_control *ctl);
 
 /*
  * our d_ops vary depending on whether the inode is live,