This is a defensive patch, but solve a problem we found on the test cluster. The
problem is tricky:
init_vdi_state() errorr out as "failed to read inode header xxx, 0".
After a detailed log analyzing, we found that the cause of this problem is
mismatch of object of path between get_obj_path() and its real path, e.g,
- disk1/oidA (real location)
- disk3/oidA (get_obj_path() location)
So default_read() fails.
To solve this problem and any future problems caused by misplaced object (if any
by any unexpected reason), we call default_exist() before default_{read, write}.
By this means, all the misplaced objects will be placed properly before
any read/write operations.
Signed-off-by: Liu Yuan <namei.unix at gmail.com>
---
sheep/plain_store.c | 34 +++++++++++++++++++++++++++++++---
1 file changed, 31 insertions(+), 3 deletions(-)
diff --git a/sheep/plain_store.c b/sheep/plain_store.c
index 9a4871c..90ef0a6 100644
--- a/sheep/plain_store.c
+++ b/sheep/plain_store.c
@@ -77,6 +77,10 @@ static int get_stale_obj_path(uint64_t oid, uint32_t epoch, char *path,
return md_get_stale_path(oid, epoch, path, size);
}
+/*
+ * Check if oid is in this nodes (if oid is in the wrong place, it will be moved
+ * to the correct one after this call in a MD setup.
+ */
bool default_exist(uint64_t oid)
{
return md_exist(oid);
@@ -142,6 +146,14 @@ int default_write(uint64_t oid, const struct siocb *iocb)
get_obj_path(oid, path, sizeof(path));
+ /*
+ * Make sure oid is in the right place because oid might be misplaced
+ * in a wrong place, due to 'shutdown/restart with less/more disks' or
+ * any bugs. We need call err_to_sderr() to return EIO if disk is broken
+ */
+ if (!default_exist(oid))
+ return err_to_sderr(path, oid, ENOENT);
+
fd = open(path, flags, sd_def_fmode);
if (unlikely(fd < 0))
return err_to_sderr(path, oid, errno);
@@ -210,8 +222,8 @@ static int init_vdi_state(uint64_t oid, const char *wd, uint32_t epoch)
ret = default_read(oid, &iocb);
if (ret != SD_RES_SUCCESS) {
- sd_err("failed to read inode header %" PRIx64 " %" PRId32, oid,
- epoch);
+ sd_err("failed to read inode header %" PRIx64 " %" PRId32
+ "wat %s", oid, epoch, wd);
goto out;
}
@@ -232,7 +244,8 @@ static int init_objlist_and_vdi_bitmap(uint64_t oid, const char *wd,
objlist_cache_insert(oid);
if (is_vdi_obj(oid)) {
- sd_debug("found the VDI object %" PRIx64, oid);
+ sd_debug("found the VDI object %" PRIx64" epoch %"PRIu32
+ " at %s", oid, epoch, wd);
ret = init_vdi_state(oid, wd, epoch);
if (ret != SD_RES_SUCCESS)
return ret;
@@ -254,6 +267,11 @@ int default_init(void)
return for_each_object_in_wd(init_objlist_and_vdi_bitmap, true, NULL);
}
+static inline bool is_stale_path(const char *path)
+{
+ return !!strstr(path, "stale");
+}
+
static int default_read_from_path(uint64_t oid, const char *path,
const struct siocb *iocb)
{
@@ -261,6 +279,16 @@ static int default_read_from_path(uint64_t oid, const char *path,
ret = SD_RES_SUCCESS;
ssize_t size;
+ /*
+ * Make sure oid is in the right place because oid might be misplaced
+ * in a wrong place, due to 'shutdown/restart with less disks' or any
+ * bugs. We need call err_to_sderr() to return EIO if disk is broken.
+ *
+ * For stale path, get_stale_obj_path() already does default_exist job.
+ */
+ if (!is_stale_path(path) && !default_exist(oid))
+ return err_to_sderr(path, oid, ENOENT);
+
fd = open(path, flags);
if (fd < 0)
--
1.8.1.2
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