1 files changed, 105 insertions, 35 deletions

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index e954ea2..4850c36 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -69,16 +69,42 @@ out_unlock:
 }
 
 /*
- * for readdir, we encode the directory frag and offset within that
- * frag into f_pos.
+ * for f_pos for readdir:
+ * - hash order:
+ *	(0xff << 52) | ((24 bits hash) << 28) |
+ *	(the nth entry has hash collision);
+ * - frag+name order;
+ *	((frag value) << 28) | (the nth entry in frag);
  */
+#define OFFSET_BITS	28
+#define OFFSET_MASK	((1 << OFFSET_BITS) - 1)
+#define HASH_ORDER	(0xffull << (OFFSET_BITS + 24))
+loff_t ceph_make_fpos(unsigned high, unsigned off, bool hash_order)
+{
+	loff_t fpos = ((loff_t)high << 28) | (loff_t)off;
+	if (hash_order)
+		fpos |= HASH_ORDER;
+	return fpos;
+}
+
+static bool is_hash_order(loff_t p)
+{
+	return (p & HASH_ORDER) == HASH_ORDER;
+}
+
 static unsigned fpos_frag(loff_t p)
 {
-	return p >> 32;
+	return p >> OFFSET_BITS;
 }
+
+static unsigned fpos_hash(loff_t p)
+{
+	return ceph_frag_value(fpos_frag(p));
+}
+
 static unsigned fpos_off(loff_t p)
 {
-	return p & 0xffffffff;
+	return p & OFFSET_MASK;
 }
 
 static int fpos_cmp(loff_t l, loff_t r)
@@ -177,7 +203,7 @@ static int __dcache_readdir(struct file *file,  struct dir_context *ctx,
 	u64 idx = 0;
 	int err = 0;
 
-	dout("__dcache_readdir %p v%u at %llu\n", dir, shared_gen, ctx->pos);
+	dout("__dcache_readdir %p v%u at %llx\n", dir, shared_gen, ctx->pos);
 
 	/* search start position */
 	if (ctx->pos > 2) {
@@ -234,7 +260,7 @@ static int __dcache_readdir(struct file *file,  struct dir_context *ctx,
 		spin_unlock(&dentry->d_lock);
 
 		if (emit_dentry) {
-			dout(" %llu (%llu) dentry %p %pd %p\n", di->offset, ctx->pos,
+			dout(" %llx dentry %p %pd %p\n", di->offset,
 			     dentry, dentry, d_inode(dentry));
 			ctx->pos = di->offset;
 			if (!dir_emit(ctx, dentry->d_name.name,
@@ -269,6 +295,16 @@ out:
 	return err;
 }
 
+static bool need_send_readdir(struct ceph_file_info *fi, loff_t pos)
+{
+	if (!fi->last_readdir)
+		return true;
+	if (is_hash_order(pos))
+		return !ceph_frag_contains_value(fi->frag, fpos_hash(pos));
+	else
+		return fi->frag != fpos_frag(pos);
+}
+
 static int ceph_readdir(struct file *file, struct dir_context *ctx)
 {
 	struct ceph_file_info *fi = file->private_data;
@@ -276,7 +312,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 	struct ceph_mds_client *mdsc = fsc->mdsc;
-	unsigned frag = fpos_frag(ctx->pos);
 	int i;
 	int err;
 	u32 ftype;
@@ -317,7 +352,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 		err = __dcache_readdir(file, ctx, shared_gen);
 		if (err != -EAGAIN)
 			return err;
-		frag = fpos_frag(ctx->pos);
 	} else {
 		spin_unlock(&ci->i_ceph_lock);
 	}
@@ -325,8 +359,9 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 	/* proceed with a normal readdir */
 more:
 	/* do we have the correct frag content buffered? */
-	if (fi->frag != frag || fi->last_readdir == NULL) {
+	if (need_send_readdir(fi, ctx->pos)) {
 		struct ceph_mds_request *req;
+		unsigned frag;
 		int op = ceph_snap(inode) == CEPH_SNAPDIR ?
 			CEPH_MDS_OP_LSSNAP : CEPH_MDS_OP_READDIR;
 
@@ -336,6 +371,13 @@ more:
 			fi->last_readdir = NULL;
 		}
 
+		if (is_hash_order(ctx->pos)) {
+			frag = ceph_choose_frag(ci, fpos_hash(ctx->pos),
+						NULL, NULL);
+		} else {
+			frag = fpos_frag(ctx->pos);
+		}
+
 		dout("readdir fetching %llx.%llx frag %x offset '%s'\n",
 		     ceph_vinop(inode), frag, fi->last_name);
 		req = ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS);
@@ -373,19 +415,23 @@ more:
 			ceph_mdsc_put_request(req);
 			return err;
 		}
-		dout("readdir got and parsed readdir result=%d"
-		     " on frag %x, end=%d, complete=%d\n", err, frag,
+		dout("readdir got and parsed readdir result=%d on "
+		     "frag %x, end=%d, complete=%d, hash_order=%d\n",
+		     err, frag,
 		     (int)req->r_reply_info.dir_end,
-		     (int)req->r_reply_info.dir_complete);
-
+		     (int)req->r_reply_info.dir_complete,
+		     (int)req->r_reply_info.hash_order);
 
-		/* 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);
-			fi->next_offset = req->r_readdir_offset;
-			/* adjust ctx->pos to beginning of frag */
-			ctx->pos = ceph_make_fpos(frag, fi->next_offset);
+			if (!rinfo->hash_order) {
+				fi->next_offset = req->r_readdir_offset;
+				/* adjust ctx->pos to beginning of frag */
+				ctx->pos = ceph_make_fpos(frag,
+							  fi->next_offset,
+							  false);
+			}
 		}
 
 		fi->frag = frag;
@@ -411,23 +457,25 @@ more:
 			fi->dir_release_count = 0;
 		}
 
-		if (req->r_reply_info.dir_end) {
-			kfree(fi->last_name);
-			fi->last_name = NULL;
-			fi->next_offset = 2;
-		} else {
+		/* note next offset and last dentry name */
+		if (rinfo->dir_nr > 0) {
 			struct ceph_mds_reply_dir_entry *rde =
 					rinfo->dir_entries + (rinfo->dir_nr-1);
+			unsigned next_offset = req->r_reply_info.dir_end ?
+					2 : (fpos_off(rde->offset) + 1);
 			err = note_last_dentry(fi, rde->name, rde->name_len,
-					       fpos_off(rde->offset) + 1);
+					       next_offset);
 			if (err)
 				return err;
+		} else if (req->r_reply_info.dir_end) {
+			fi->next_offset = 2;
+			/* keep last name */
 		}
 	}
 
 	rinfo = &fi->last_readdir->r_reply_info;
 	dout("readdir frag %x num %d pos %llx chunk first %llx\n",
-	     frag, rinfo->dir_nr, ctx->pos,
+	     fi->frag, rinfo->dir_nr, ctx->pos,
 	     rinfo->dir_nr ? rinfo->dir_entries[0].offset : 0LL);
 
 	i = 0;
@@ -470,16 +518,26 @@ more:
 		ctx->pos++;
 	}
 
-	if (fi->last_name) {
+	if (fi->next_offset > 2) {
 		ceph_mdsc_put_request(fi->last_readdir);
 		fi->last_readdir = NULL;
 		goto more;
 	}
 
 	/* more frags? */
-	if (!ceph_frag_is_rightmost(frag)) {
-		frag = ceph_frag_next(frag);
-		ctx->pos = ceph_make_fpos(frag, 2);
+	if (!ceph_frag_is_rightmost(fi->frag)) {
+		unsigned frag = ceph_frag_next(fi->frag);
+		if (is_hash_order(ctx->pos)) {
+			loff_t new_pos = ceph_make_fpos(ceph_frag_value(frag),
+							fi->next_offset, true);
+			if (new_pos > ctx->pos)
+				ctx->pos = new_pos;
+			/* keep last_name */
+		} else {
+			ctx->pos = ceph_make_fpos(frag, fi->next_offset, false);
+			kfree(fi->last_name);
+			fi->last_name = NULL;
+		}
 		dout("readdir next frag is %x\n", frag);
 		goto more;
 	}
@@ -532,14 +590,21 @@ static void reset_readdir(struct ceph_file_info *fi)
 static bool need_reset_readdir(struct ceph_file_info *fi, loff_t new_pos)
 {
 	struct ceph_mds_reply_info_parsed *rinfo;
+	loff_t chunk_offset;
 	if (new_pos == 0)
 		return true;
-	if (fpos_frag(new_pos) != fi->frag)
+	if (is_hash_order(new_pos)) {
+		/* no need to reset last_name for a forward seek when
+		 * dentries are sotred in hash order */
+	} else if (fi->frag |= fpos_frag(new_pos)) {
 		return true;
+	}
 	rinfo = fi->last_readdir ? &fi->last_readdir->r_reply_info : NULL;
 	if (!rinfo || !rinfo->dir_nr)
 		return true;
-	return new_pos < rinfo->dir_entries[0].offset;;
+	chunk_offset = rinfo->dir_entries[0].offset;
+	return new_pos < chunk_offset ||
+	       is_hash_order(new_pos) != is_hash_order(chunk_offset);
 }
 
 static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
@@ -562,17 +627,22 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
 	}
 
 	if (offset >= 0) {
+		if (need_reset_readdir(fi, offset)) {
+			dout("dir_llseek dropping %p content\n", file);
+			reset_readdir(fi);
+		} else if (is_hash_order(offset) && offset > file->f_pos) {
+			/* for hash offset, we don't know if a forward seek
+			 * is within same frag */
+			fi->dir_release_count = 0;
+			fi->readdir_cache_idx = -1;
+		}
+
 		if (offset != file->f_pos) {
 			file->f_pos = offset;
 			file->f_version = 0;
 			fi->flags &= ~CEPH_F_ATEND;
 		}
 		retval = offset;
-
-		if (need_reset_readdir(fi, offset)) {
-			dout("dir_llseek dropping %p content\n", file);
-			reset_readdir(fi);
-		}
 	}
 out:
 	inode_unlock(inode);