[Sheepdog] [PATCH v2 2/2] sheep: abstract out store IO interface

Liu Yuan namei.unix at gmail.com
Wed Nov 16 13:59:20 CET 2011


From: Liu Yuan <tailai.ly at taobao.com>

We need to abstract out store IO interface to adopt it to other IO store
such as the coming 'Farm' store.

The open/read/write/close is cumbersome for a common kv-store to work with,
but this interface request smallest changes to current sheep store code. It
sucks but works as a kludge.

We can refine it later to more common get/put/delete interface.

Signed-off-by: Liu Yuan <tailai.ly at taobao.com>
---
 sheep/sheep_priv.h |   11 +++
 sheep/store.c      |  216 +++++++++++++++++++++++++++++++++------------------
 2 files changed, 151 insertions(+), 76 deletions(-)

diff --git a/sheep/sheep_priv.h b/sheep/sheep_priv.h
index ee4deb4..56b9a99 100644
--- a/sheep/sheep_priv.h
+++ b/sheep/sheep_priv.h
@@ -156,6 +156,17 @@ struct cluster_info {
 	struct work_queue *recovery_wqueue;
 };
 
+struct store_driver {
+	const char *driver_name;
+	int (*init)(char *path);
+	int (*open)(uint64_t oid, void *priv, int create);
+	ssize_t (*write)(uint64_t oid, void *priv, void *buf, int len, off_t offset);
+	ssize_t (*read)(uint64_t oid, void *priv, void *buf, int len, off_t offset);
+	int (*close)(uint64_t oid, void *priv);
+};
+
+extern void register_store_driver(struct store_driver *);
+
 extern struct cluster_info *sys;
 
 int create_listen_port(int port, void *data);
diff --git a/sheep/store.c b/sheep/store.c
index 3a04c34..a6d865f 100644
--- a/sheep/store.c
+++ b/sheep/store.c
@@ -24,6 +24,8 @@
 #include <time.h>
 
 #include "sheep_priv.h"
+#include "strbuf.h"
+#include "util.h"
 
 struct sheepdog_config {
 	uint64_t ctime;
@@ -41,6 +43,92 @@ static char *config_path;
 static mode_t def_dmode = S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP;
 static mode_t def_fmode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
 
+static int def_store_flags = O_DSYNC | O_RDWR;
+
+static int default_store_init(char *path)
+{
+	eprintf("Use default store driver\n");
+	return 0;
+}
+
+static int default_store_open(uint64_t oid, void *priv, int create)
+{
+	struct strbuf path = STRBUF_INIT;
+	int ret;
+	int flags = def_store_flags;
+	int epoch = *(int *)priv;
+
+	if (sys->use_directio && is_data_obj(oid))
+		flags |= O_DIRECT;
+
+	if (create)
+		flags |= O_CREAT | O_TRUNC;
+
+	strbuf_addf(&path, "%s%08u/%016" PRIx64, obj_path, epoch, oid);
+
+	ret = open(path.buf, flags, def_fmode);
+	if (ret < 0) {
+		eprintf("failed to open %s: %m\n", path.buf);
+		if (errno == ENOENT) {
+			struct stat s;
+
+			ret = SD_RES_NO_OBJ;
+			if (stat(obj_path, &s) < 0) {
+				/* store directory is corrupted */
+				eprintf("corrupted\n");
+				ret = SD_RES_EIO;
+			}
+		} else
+			ret = SD_RES_UNKNOWN;
+		goto out;
+	}
+
+	*(int *)priv = ret;
+	ret = SD_RES_SUCCESS;
+out:
+	strbuf_release(&path);
+	return ret;
+}
+
+static ssize_t default_store_write(uint64_t oid, void *priv, void *buf, int len, off_t offset)
+{
+	int fd = *(int *)priv;
+
+	return xpwrite(fd, buf, len, offset);
+}
+
+static ssize_t default_store_read(uint64_t oid, void *priv, void *buf, int len, off_t offset)
+{
+	int fd = *(int *)priv;
+
+	return xpread(fd, buf, len, offset);
+}
+
+static int default_store_close(uint64_t oid, void *priv)
+{
+	int fd = *(int *)priv;
+
+	if (close(fd) < 0)
+		return SD_RES_EIO;
+
+	return SD_RES_SUCCESS;
+}
+
+static struct store_driver store = {
+	.driver_name = "default",
+	.init = default_store_init,
+	.open = default_store_open,
+	.write = default_store_write,
+	.read = default_store_read,
+	.close = default_store_close
+};
+
+void register_store_driver(struct store_driver *driver)
+{
+	store = *driver;
+	eprintf("Register %s store driver\n", store.driver_name);
+}
+
 static int obj_cmp(const void *oid1, const void *oid2)
 {
 	const uint64_t hval1 = fnv_64a_buf((void *)oid1, sizeof(uint64_t), FNV1A_64_INIT);
@@ -158,17 +246,17 @@ out:
 	return res;
 }
 
-static int ob_open(uint32_t epoch, uint64_t oid, int flags, int *ret);
-
 static int read_from_one(struct request *req, uint32_t epoch, uint64_t oid,
 			 unsigned *ori_rlen, void *buf, uint64_t offset)
 {
-	int i, n, nr, fd, ret;
+	int i, n, nr, ret;
 	unsigned wlen, rlen;
 	char name[128];
 	struct sheepdog_vnode_list_entry *e;
 	struct sd_obj_req hdr;
 	struct sd_obj_rsp *rsp = (struct sd_obj_rsp *)&hdr;
+	int opaque = epoch;
+	int fd;
 
 	e = req->entry;
 	nr = req->nr_vnodes;
@@ -179,15 +267,16 @@ static int read_from_one(struct request *req, uint32_t epoch, uint64_t oid,
 		addr_to_str(name, sizeof(name), e[n].addr, 0);
 
 		if (is_myself(e[n].addr, e[n].port)) {
-			fd = ob_open(epoch, oid, 0, &ret);
-			if (fd < 0 || ret != 0)
+			ret = store.open(oid, &opaque, 0);
+			if (ret != SD_RES_SUCCESS)
 				continue;
 
-			ret = pread64(fd, buf, *ori_rlen, offset);
+			ret = store.read(oid, &opaque, buf, *ori_rlen, offset);
 			if (ret < 0)
 				continue;
 			*ori_rlen = ret;
 			ret = 0;
+			store.close(oid, &opaque);
 			goto out;
 		}
 
@@ -430,37 +519,6 @@ out:
 	return ret;
 }
 
-static int ob_open(uint32_t epoch, uint64_t oid, int flags, int *ret)
-{
-	char path[1024];
-	int fd;
-
-	flags |= O_DSYNC | O_RDWR;
-	if (sys->use_directio && is_data_obj(oid))
-		flags |= O_DIRECT;
-
-	snprintf(path, sizeof(path), "%s%08u/%016" PRIx64, obj_path, epoch, oid);
-
-	fd = open(path, flags, def_fmode);
-	if (fd < 0) {
-		eprintf("failed to open %s: %m\n", path);
-		if (errno == ENOENT) {
-			struct stat s;
-
-			*ret = SD_RES_NO_OBJ;
-			if (stat(obj_path, &s) < 0) {
-				/* store directory is corrupted */
-				eprintf("corrupted\n");
-				*ret = SD_RES_EIO;
-			}
-		} else
-			*ret = SD_RES_UNKNOWN;
-	} else
-		*ret = 0;
-
-	return fd;
-}
-
 int update_epoch_store(uint32_t epoch)
 {
 	char new[1024];
@@ -597,13 +655,13 @@ static int store_read_obj(struct request *req, uint32_t epoch)
 	struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
 	struct sd_obj_rsp *rsp = (struct sd_obj_rsp *)&req->rp;
 	int ret = SD_RES_SUCCESS;
-	int fd = -1;
+	int opaque = epoch;
 
-	fd = ob_open(epoch, hdr->oid, 0, &ret);
-	if (fd < 0)
+	ret = store.open(hdr->oid, &opaque, 0);
+	if (ret != SD_RES_SUCCESS)
 		return ret;
 
-	ret = pread64(fd, req->data, hdr->data_length, hdr->offset);
+	ret = store.read(hdr->oid, &opaque, req->data, hdr->data_length, hdr->offset);
 	if (ret < 0) {
 		eprintf("%m\n");
 		ret = SD_RES_EIO;
@@ -615,15 +673,16 @@ static int store_read_obj(struct request *req, uint32_t epoch)
 
 	ret = SD_RES_SUCCESS;
 out:
-	close(fd);
+	store.close(hdr->oid, &opaque);
 	return ret;
 }
 
-static int store_write_obj_fd(int fd, struct request *req, uint32_t epoch)
+static int store_write_obj_fd(void *opaque, struct request *req, uint32_t epoch)
 {
 	struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
 	uint64_t oid = hdr->oid;
 	int ret = SD_RES_SUCCESS;
+	int fd = *(int *)opaque;
 
 	if (hdr->flags & SD_FLAG_CMD_TRUNCATE) {
 		ret = ftruncate(fd, hdr->offset + hdr->data_length);
@@ -643,7 +702,7 @@ static int store_write_obj_fd(int fd, struct request *req, uint32_t epoch)
 		if (ret)
 			return ret;
 	}
-	ret = pwrite64(fd, req->data, hdr->data_length, hdr->offset);
+	ret = store.write(oid, opaque, req->data, hdr->data_length, hdr->offset);
 	if (ret != hdr->data_length) {
 		if (errno == ENOSPC)
 			return SD_RES_NO_SPACE;
@@ -657,24 +716,24 @@ static int store_write_obj_fd(int fd, struct request *req, uint32_t epoch)
 static int store_write_obj(struct request *req, uint32_t epoch)
 {
 	struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
-	int ret = SD_RES_SUCCESS;
-	int fd = -1;
+	int ret;
+	int opaque = epoch;
 
-	fd = ob_open(epoch, hdr->oid, 0, &ret);
-	if (fd < 0)
+	ret = store.open(hdr->oid, &opaque, 0);
+	if (ret != SD_RES_SUCCESS)
 		return ret;
 
-	ret = store_write_obj_fd(fd, req, epoch);
+	ret = store_write_obj_fd(&opaque, req, epoch);
 
-	close(fd);
+	store.close(hdr->oid, &opaque);
 	return ret;
 }
 
 static int store_create_and_write_obj_cow(struct request *req, uint32_t epoch)
 {
 	struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
-	int ret = SD_RES_SUCCESS;
-	int fd = -1;
+	int ret;
+	int opaque = epoch;
 	char *buf = NULL;
 
 	if (!hdr->copies) {
@@ -682,8 +741,8 @@ static int store_create_and_write_obj_cow(struct request *req, uint32_t epoch)
 		return SD_RES_INVALID_PARMS;
 	}
 
-	fd = ob_open(epoch, hdr->oid, O_CREAT|O_TRUNC, &ret);
-	if (fd < 0)
+	ret = store.open(hdr->oid, &opaque, 1);
+	if (ret != SD_RES_SUCCESS)
 		return ret;
 
 	dprintf("%" PRIu64 ", %" PRIx64 "\n", hdr->oid, hdr->cow_oid);
@@ -701,7 +760,7 @@ static int store_create_and_write_obj_cow(struct request *req, uint32_t epoch)
 		ret = SD_RES_EIO;
 		goto out;
 	}
-	ret = pwrite64(fd, buf, SD_DATA_OBJ_SIZE, 0);
+	ret = store.write(hdr->oid, &opaque, buf, SD_DATA_OBJ_SIZE, 0);
 	if (ret != SD_DATA_OBJ_SIZE) {
 		if (errno == ENOSPC)
 			ret = SD_RES_NO_SPACE;
@@ -714,15 +773,15 @@ static int store_create_and_write_obj_cow(struct request *req, uint32_t epoch)
 	free(buf);
 	buf = NULL;
 
-	ret = store_write_obj_fd(fd, req, epoch);
+	ret = store_write_obj_fd(&opaque, req, epoch);
 out:
 	if (buf)
 		free(buf);
-	close(fd);
+	store.close(hdr->oid, &opaque);
 	return ret;
 }
 
-static int store_write_last_sector(int fd)
+static int store_write_last_sector(uint64_t oid, void *opaque)
 {
 	const int size = SECTOR_SIZE;
 	char *buf = NULL;
@@ -735,7 +794,7 @@ static int store_write_last_sector(int fd)
 	}
 
 	memset(buf, 0, size);
-	ret = pwrite64(fd, buf, size, SD_DATA_OBJ_SIZE - size);
+	ret = store.write(oid, opaque, buf, size, SD_DATA_OBJ_SIZE - size);
 	free(buf);
 
 	if (ret != size) {
@@ -751,34 +810,34 @@ static int store_write_last_sector(int fd)
 static int store_create_and_write_obj(struct request *req, uint32_t epoch)
 {
 	struct sd_obj_req *hdr = (struct sd_obj_req *)&req->rq;
-	int ret = SD_RES_SUCCESS;
-	int fd = -1;
+	int ret;
+	int opaque = epoch;
 
 	if (!hdr->copies) {
 		eprintf("the number of copies cannot be zero\n");
 		return SD_RES_INVALID_PARMS;
 	}
 
-	fd = ob_open(epoch, hdr->oid, O_CREAT|O_TRUNC, &ret);
-	if (fd < 0)
+	ret = store.open(hdr->oid, &opaque, 1);
+	if (ret != SD_RES_SUCCESS)
 		return ret;
 
 	/*
 	 * Preallocate the whole object to get a better filesystem layout.
 	 */
-	ret = fallocate(fd, 0, 0, SD_DATA_OBJ_SIZE);
+	ret = fallocate(opaque, 0, 0, SD_DATA_OBJ_SIZE);
 	if (ret < 0) {
 		if (errno != ENOSYS && errno != EOPNOTSUPP) {
 			ret = SD_RES_EIO;
 			goto out;
 		}
 
-		ret = store_write_last_sector(fd);
+		ret = store_write_last_sector(hdr->oid, &opaque);
 	}
-
-	ret = store_write_obj_fd(fd, req, epoch);
+	
+	ret = store_write_obj_fd(&opaque, req, epoch);
 out:
-	close(fd);
+	store.close(hdr->oid, &opaque);
 	return ret;
 }
 
@@ -1489,14 +1548,14 @@ static void recover_one(struct work *work, int idx)
 	int old_copies, cur_copies;
 	uint32_t epoch = rw->epoch;
 	int i, copy_idx = 0, cur_idx = -1;
-	int fd;
+	int opaque = epoch;
 
 	eprintf("%"PRIu32" %"PRIu32", %16"PRIx64"\n", rw->done, rw->count, oid);
 
-	fd = ob_open(epoch, oid, 0, &ret);
-	if (fd != -1) {
+	ret = store.open(oid, &opaque, 0);
+	if (ret == SD_RES_SUCCESS) {
 		/* the object is already recovered */
-		close(fd);
+		store.close(oid, &opaque);
 		goto out;
 	}
 
@@ -1595,7 +1654,8 @@ int is_recoverying_oid(uint64_t oid)
 	uint64_t hval = fnv_64a_buf(&oid, sizeof(uint64_t), FNV1A_64_INIT);
 	uint64_t min_hval;
 	struct recovery_work *rw = recovering_work;
-	int ret, fd, i;
+	int ret, i;
+	int opaque = sys->epoch;
 
 	if (oid == 0)
 		return 0;
@@ -1611,10 +1671,10 @@ int is_recoverying_oid(uint64_t oid)
 	if (rw->state == RW_INIT)
 		return 1;
 
-	fd = ob_open(sys->epoch, oid, 0, &ret);
-	if (fd != -1) {
+	ret = store.open(oid, &opaque, 0);
+	if (ret == SD_RES_SUCCESS) {
 		dprintf("the object %" PRIx64 " is already recoverd\n", oid);
-		close(fd);
+		store.close(oid, &opaque);
 		return 0;
 	}
 
@@ -2105,6 +2165,10 @@ int init_store(const char *d)
 	if (ret)
 		return ret;
 
+	ret = store.init(obj_path);
+	if (ret)
+		return ret;
+
 	return ret;
 }
 
-- 
1.7.6.1




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