libzutil: optimize zpool_read_label with AIO

Read all labels in parallel instead of sequentially.

Originally committed as
https://cgit.freebsd.org/src/commit/?id=b49e9abcf44cafaf5cfad7029c9a6adbb28346e8

Obtained from: FreeBSD
Sponsored by: Spectra Logic, Axcient
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alek Pinchuk <apinchuk@axcient.com>
Signed-off-by: Alan Somers <asomers@gmail.com>
Closes #11467

diff --git a/lib/libzutil/Makefile.am b/lib/libzutil/Makefile.am
index 1b55ef68074a9aaffda4efa22cc34fda26a8c5fa..9cfb0de058d537103db504334caf50b192132c28 100644 (file)
--- a/lib/libzutil/Makefile.am
+++ b/lib/libzutil/Makefile.am
@@ -45,7 +45,8 @@ libzutil_la_LIBADD = \
 
 if BUILD_LINUX
 libzutil_la_LIBADD += \
-        $(abs_top_builddir)/lib/libefi/libefi.la
+       $(abs_top_builddir)/lib/libefi/libefi.la \
+       -lrt
 endif
 
 libzutil_la_LIBADD += -lm $(LIBBLKID_LIBS) $(LIBUDEV_LIBS)

diff --git a/lib/libzutil/zutil_import.c b/lib/libzutil/zutil_import.c
index bf914d37c8b2280ffe7b91399ecc402b46d03806..823f093f409fdd40aac2d1599491861452aa2fda 100644 (file)
--- a/lib/libzutil/zutil_import.c
+++ b/lib/libzutil/zutil_import.c
@@ -46,6 +46,7 @@
  * using our derived config, and record the results.
  */
 
+#include <aio.h>
 #include <ctype.h>
 #include <dirent.h>
 #include <errno.h>
@@ -887,11 +888,12 @@ int
 zpool_read_label(int fd, nvlist_t **config, int *num_labels)
 {
        struct stat64 statbuf;
-       int l, count = 0;
-       vdev_phys_t *label;
+       struct aiocb aiocbs[VDEV_LABELS];
+       struct aiocb *aiocbps[VDEV_LABELS];
+       vdev_phys_t *labels;
        nvlist_t *expected_config = NULL;
        uint64_t expected_guid = 0, size;
-       int error;
+       int error, l, count = 0;
 
        *config = NULL;
 
@@ -899,20 +901,51 @@ zpool_read_label(int fd, nvlist_t **config, int *num_labels)
                return (0);
        size = P2ALIGN_TYPED(statbuf.st_size, sizeof (vdev_label_t), uint64_t);
 
-       error = posix_memalign((void **)&label, PAGESIZE, sizeof (*label));
+       error = posix_memalign((void **)&labels, PAGESIZE,
+           VDEV_LABELS * sizeof (*labels));
        if (error)
                return (-1);
 
+       memset(aiocbs, 0, sizeof (aiocbs));
        for (l = 0; l < VDEV_LABELS; l++) {
-               uint64_t state, guid, txg;
                off_t offset = label_offset(size, l) + VDEV_SKIP_SIZE;
 
-               if (pread64(fd, label, sizeof (vdev_phys_t),
-                   offset) != sizeof (vdev_phys_t))
+               aiocbs[l].aio_fildes = fd;
+               aiocbs[l].aio_offset = offset;
+               aiocbs[l].aio_buf = &labels[l];
+               aiocbs[l].aio_nbytes = sizeof (vdev_phys_t);
+               aiocbs[l].aio_lio_opcode = LIO_READ;
+               aiocbps[l] = &aiocbs[l];
+       }
+
+       if (lio_listio(LIO_WAIT, aiocbps, VDEV_LABELS, NULL) != 0) {
+               int saved_errno = errno;
+
+               if (errno == EAGAIN || errno == EINTR || errno == EIO) {
+                       /*
+                        * A portion of the requests may have been submitted.
+                        * Clean them up.
+                        */
+                       for (l = 0; l < VDEV_LABELS; l++) {
+                               errno = 0;
+                               int r = aio_error(&aiocbs[l]);
+                               if (r != EINVAL)
+                                       (void) aio_return(&aiocbs[l]);
+                       }
+               }
+               free(labels);
+               errno = saved_errno;
+               return (-1);
+       }
+
+       for (l = 0; l < VDEV_LABELS; l++) {
+               uint64_t state, guid, txg;
+
+               if (aio_return(&aiocbs[l]) != sizeof (vdev_phys_t))
                        continue;
 
-               if (nvlist_unpack(label->vp_nvlist,
-                   sizeof (label->vp_nvlist), config, 0) != 0)
+               if (nvlist_unpack(labels[l].vp_nvlist,
+                   sizeof (labels[l].vp_nvlist), config, 0) != 0)
                        continue;
 
                if (nvlist_lookup_uint64(*config, ZPOOL_CONFIG_GUID,
@@ -949,7 +982,7 @@ zpool_read_label(int fd, nvlist_t **config, int *num_labels)
        if (num_labels != NULL)
                *num_labels = count;
 
-       free(label);
+       free(labels);
        *config = expected_config;
 
        return (0);