[PATCH 0/5] block: file-posix queue

[PATCH 0/5] block: file-posix queue

[Paolo Bonzini]

Hi Max/Kevin,

this is a combination of two series that both affect host block device
support in block/file-posix.c.  I suspect both of them evaded your radar,
so I'm grouping them together and sending them out again.

Joelle van Dyne (3):
  block: feature detection for host block support
  block: check for sys/disk.h
  block: detect DKIOCGETBLOCKCOUNT/SIZE before use

Paolo Bonzini (2):
  file-posix: try BLKSECTGET on block devices too, do not round to power
    of 2
  file-posix: fix max_iov for /dev/sg devices

 block.c              |   2 +-
 block/file-posix.c   | 101 ++++++++++++++++++++++++++-----------------
 meson.build          |   7 ++-
 qapi/block-core.json |  10 +++--
 4 files changed, 76 insertions(+), 44 deletions(-)

-- 
2.31.1

[PATCH 1/5] file-posix: try BLKSECTGET on block devices too, do not round to power of 2

[Paolo Bonzini]

bs->sg is only true for character devices, but block devices can also
be used with scsi-block and scsi-generic.  Unfortunately BLKSECTGET
returns bytes in an int for /dev/sgN devices, and sectors in a short
for block devices, so account for that in the code.

The maximum transfer also need not be a power of 2 (for example I have
seen disks with 1280 KiB maximum transfer) so there's no need to pass
the result through pow2floor.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/file-posix.c | 40 ++++++++++++++++++++++------------------
 1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 59c889d5a7..e5ef006aee 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1149,22 +1149,27 @@ static void raw_reopen_abort(BDRVReopenState *state)
     s->reopen_state = NULL;
 }
 
-static int sg_get_max_transfer_length(int fd)
+static int sg_get_max_transfer_length(int fd, struct stat *st)
 {
 #ifdef BLKSECTGET
-    int max_bytes = 0;
-
-    if (ioctl(fd, BLKSECTGET, &max_bytes) == 0) {
-        return max_bytes;
+    if (S_ISBLK(st->st_mode)) {
+        unsigned short max_sectors = 0;
+        if (ioctl(fd, BLKSECTGET, &max_sectors) == 0) {
+            return max_sectors * 512;
+        }
     } else {
-        return -errno;
+        int max_bytes = 0;
+        if (ioctl(fd, BLKSECTGET, &max_bytes) == 0) {
+            return max_bytes;
+        }
     }
+    return -errno;
 #else
     return -ENOSYS;
 #endif
 }
 
-static int sg_get_max_segments(int fd)
+static int sg_get_max_segments(int fd, struct stat *st)
 {
 #ifdef CONFIG_LINUX
     char buf[32];
@@ -1173,15 +1178,9 @@ static int sg_get_max_segments(int fd)
     int ret;
     int sysfd = -1;
     long max_segments;
-    struct stat st;
-
-    if (fstat(fd, &st)) {
-        ret = -errno;
-        goto out;
-    }
 
     sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/max_segments",
-                                major(st.st_rdev), minor(st.st_rdev));
+                                major(st->st_rdev), minor(st->st_rdev));
     sysfd = open(sysfspath, O_RDONLY);
     if (sysfd == -1) {
         ret = -errno;
@@ -1218,15 +1217,20 @@ out:
 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 {
     BDRVRawState *s = bs->opaque;
+    struct stat st;
+
+    if (fstat(s->fd, &st)) {
+        return;
+    }
 
-    if (bs->sg) {
-        int ret = sg_get_max_transfer_length(s->fd);
+    if (bs->sg || S_ISBLK(st.st_mode)) {
+        int ret = sg_get_max_transfer_length(s->fd, &st);
 
         if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) {
-            bs->bl.max_transfer = pow2floor(ret);
+            bs->bl.max_transfer = ret;
         }
 
-        ret = sg_get_max_segments(s->fd);
+        ret = sg_get_max_segments(s->fd, &st);
         if (ret > 0) {
             bs->bl.max_iov = ret;
         }
-- 
2.31.1

[PATCH 2/5] file-posix: fix max_iov for /dev/sg devices

[Paolo Bonzini]

Even though it was only called for devices that have bs->sg set (which
must be character devices),
sg_get_max_segments looked at /sys/dev/block which only works for
block devices.

On Linux the sg driver has its own way to provide the maximum number of
iovecs in a scatter/gather list.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/file-posix.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/block/file-posix.c b/block/file-posix.c
index e5ef006aee..77a45083a6 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1179,6 +1179,17 @@ static int sg_get_max_segments(int fd, struct stat *st)
     int sysfd = -1;
     long max_segments;
 
+    if (S_ISCHR(st->st_mode)) {
+        if (ioctl(fd, SG_GET_SG_TABLESIZE, &ret) == 0) {
+            return ret;
+        }
+        return -EIO;
+    }
+
+    if (!S_ISBLK(st->st_mode)) {
+        return -ENOTSUP;
+    }
+
     sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/max_segments",
                                 major(st->st_rdev), minor(st->st_rdev));
     sysfd = open(sysfspath, O_RDONLY);
-- 
2.31.1

[PATCH 3/5] block: feature detection for host block support

[Paolo Bonzini]

From: Joelle van Dyne <j@getutm.app>

On Darwin (iOS), there are no system level APIs for directly accessing
host block devices. We detect this at configure time.

Signed-off-by: Joelle van Dyne <j@getutm.app>
Message-Id: <20210315180341.31638-2-j@getutm.app>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/file-posix.c   | 33 ++++++++++++++++++++++-----------
 meson.build          |  6 +++++-
 qapi/block-core.json | 10 +++++++---
 3 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 77a45083a6..e83f34a960 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -42,6 +42,8 @@
 #include "scsi/constants.h"
 
 #if defined(__APPLE__) && (__MACH__)
+#include <sys/ioctl.h>
+#if defined(HAVE_HOST_BLOCK_DEVICE)
 #include <paths.h>
 #include <sys/param.h>
 #include <IOKit/IOKitLib.h>
@@ -52,6 +54,7 @@
 //#include <IOKit/storage/IOCDTypes.h>
 #include <IOKit/storage/IODVDMedia.h>
 #include <CoreFoundation/CoreFoundation.h>
+#endif /* defined(HAVE_HOST_BLOCK_DEVICE) */
 #endif
 
 #ifdef __sun__
@@ -180,7 +183,17 @@ typedef struct BDRVRawReopenState {
     bool check_cache_dropped;
 } BDRVRawReopenState;
 
-static int fd_open(BlockDriverState *bs);
+static int fd_open(BlockDriverState *bs)
+{
+    BDRVRawState *s = bs->opaque;
+
+    /* this is just to ensure s->fd is sane (its called by io ops) */
+    if (s->fd >= 0) {
+        return 0;
+    }
+    return -EIO;
+}
+
 static int64_t raw_getlength(BlockDriverState *bs);
 
 typedef struct RawPosixAIOData {
@@ -3017,6 +3030,7 @@ static BlockStatsSpecific *raw_get_specific_stats(BlockDriverState *bs)
     return stats;
 }
 
+#if defined(HAVE_HOST_BLOCK_DEVICE)
 static BlockStatsSpecific *hdev_get_specific_stats(BlockDriverState *bs)
 {
     BlockStatsSpecific *stats = g_new(BlockStatsSpecific, 1);
@@ -3026,6 +3040,7 @@ static BlockStatsSpecific *hdev_get_specific_stats(BlockDriverState *bs)
 
     return stats;
 }
+#endif /* HAVE_HOST_BLOCK_DEVICE */
 
 static QemuOptsList raw_create_opts = {
     .name = "raw-create-opts",
@@ -3241,6 +3256,8 @@ BlockDriver bdrv_file = {
 /***********************************************/
 /* host device */
 
+#if defined(HAVE_HOST_BLOCK_DEVICE)
+
 #if defined(__APPLE__) && defined(__MACH__)
 static kern_return_t GetBSDPath(io_iterator_t mediaIterator, char *bsdPath,
                                 CFIndex maxPathSize, int flags);
@@ -3533,16 +3550,6 @@ hdev_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
 }
 #endif /* linux */
 
-static int fd_open(BlockDriverState *bs)
-{
-    BDRVRawState *s = bs->opaque;
-
-    /* this is just to ensure s->fd is sane (its called by io ops) */
-    if (s->fd >= 0)
-        return 0;
-    return -EIO;
-}
-
 static coroutine_fn int
 hdev_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes)
 {
@@ -3866,6 +3873,8 @@ static BlockDriver bdrv_host_cdrom = {
 };
 #endif /* __FreeBSD__ */
 
+#endif /* HAVE_HOST_BLOCK_DEVICE */
+
 static void bdrv_file_init(void)
 {
     /*
@@ -3873,6 +3882,7 @@ static void bdrv_file_init(void)
      * registered last will get probed first.
      */
     bdrv_register(&bdrv_file);
+#if defined(HAVE_HOST_BLOCK_DEVICE)
     bdrv_register(&bdrv_host_device);
 #ifdef __linux__
     bdrv_register(&bdrv_host_cdrom);
@@ -3880,6 +3890,7 @@ static void bdrv_file_init(void)
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
     bdrv_register(&bdrv_host_cdrom);
 #endif
+#endif /* HAVE_HOST_BLOCK_DEVICE */
 }
 
 block_init(bdrv_file_init);
diff --git a/meson.build b/meson.build
index 5cf0dce695..b3cc45c41d 100644
--- a/meson.build
+++ b/meson.build
@@ -182,7 +182,7 @@ if targetos == 'windows'
                                       include_directories: include_directories('.'))
 elif targetos == 'darwin'
   coref = dependency('appleframeworks', modules: 'CoreFoundation')
-  iokit = dependency('appleframeworks', modules: 'IOKit')
+  iokit = dependency('appleframeworks', modules: 'IOKit', required: false)
 elif targetos == 'sunos'
   socket = [cc.find_library('socket'),
             cc.find_library('nsl'),
@@ -1067,6 +1067,9 @@ if get_option('cfi')
   add_global_link_arguments(cfi_flags, native: false, language: ['c', 'cpp', 'objc'])
 endif
 
+have_host_block_device = (targetos != 'darwin' or
+    cc.has_header('IOKit/storage/IOMedia.h'))
+
 #################
 # config-host.h #
 #################
@@ -1160,6 +1163,7 @@ config_host_data.set('HAVE_PTY_H', cc.has_header('pty.h'))
 config_host_data.set('HAVE_SYS_IOCCOM_H', cc.has_header('sys/ioccom.h'))
 config_host_data.set('HAVE_SYS_KCOV_H', cc.has_header('sys/kcov.h'))
 config_host_data.set('HAVE_SYSTEM_FUNCTION', cc.has_function('system', prefix: '#include <stdlib.h>'))
+config_host_data.set('HAVE_HOST_BLOCK_DEVICE', have_host_block_device)
 
 config_host_data.set('CONFIG_PREADV', cc.has_function('preadv', prefix: '#include <sys/uio.h>'))
 
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 2ea294129e..2dd41be156 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -897,7 +897,8 @@
   'discriminator': 'driver',
   'data': {
       'file': 'BlockStatsSpecificFile',
-      'host_device': 'BlockStatsSpecificFile',
+      'host_device': { 'type': 'BlockStatsSpecificFile',
+                       'if': 'defined(HAVE_HOST_BLOCK_DEVICE)' },
       'nvme': 'BlockStatsSpecificNvme' } }
 
 ##
@@ -2814,7 +2815,9 @@
 { 'enum': 'BlockdevDriver',
   'data': [ 'blkdebug', 'blklogwrites', 'blkreplay', 'blkverify', 'bochs',
             'cloop', 'compress', 'copy-on-read', 'dmg', 'file', 'ftp', 'ftps',
-            'gluster', 'host_cdrom', 'host_device', 'http', 'https', 'iscsi',
+            'gluster', 'host_cdrom',
+            {'name': 'host_device', 'if': 'defined(HAVE_HOST_BLOCK_DEVICE)' },
+            'http', 'https', 'iscsi',
             'luks', 'nbd', 'nfs', 'null-aio', 'null-co', 'nvme', 'parallels',
             'preallocate', 'qcow', 'qcow2', 'qed', 'quorum', 'raw', 'rbd',
             { 'name': 'replication', 'if': 'defined(CONFIG_REPLICATION)' },
@@ -3996,7 +3999,8 @@
       'ftps':       'BlockdevOptionsCurlFtps',
       'gluster':    'BlockdevOptionsGluster',
       'host_cdrom': 'BlockdevOptionsFile',
-      'host_device':'BlockdevOptionsFile',
+      'host_device': { 'type': 'BlockdevOptionsFile',
+                       'if': 'defined(HAVE_HOST_BLOCK_DEVICE)' },
       'http':       'BlockdevOptionsCurlHttp',
       'https':      'BlockdevOptionsCurlHttps',
       'iscsi':      'BlockdevOptionsIscsi',
-- 
2.31.1

[PATCH 4/5] block: check for sys/disk.h

[Paolo Bonzini]

From: Joelle van Dyne <j@getutm.app>

Some BSD platforms do not have this header.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Joelle van Dyne <j@getutm.app>
Message-Id: <20210315180341.31638-3-j@getutm.app>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block.c     | 2 +-
 meson.build | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/block.c b/block.c
index 9ad725d205..86a8c638c6 100644
--- a/block.c
+++ b/block.c
@@ -54,7 +54,7 @@
 #ifdef CONFIG_BSD
 #include <sys/ioctl.h>
 #include <sys/queue.h>
-#ifndef __DragonFly__
+#if defined(HAVE_SYS_DISK_H)
 #include <sys/disk.h>
 #endif
 #endif
diff --git a/meson.build b/meson.build
index b3cc45c41d..5f0d4a1bc3 100644
--- a/meson.build
+++ b/meson.build
@@ -1164,6 +1164,7 @@ config_host_data.set('HAVE_SYS_IOCCOM_H', cc.has_header('sys/ioccom.h'))
 config_host_data.set('HAVE_SYS_KCOV_H', cc.has_header('sys/kcov.h'))
 config_host_data.set('HAVE_SYSTEM_FUNCTION', cc.has_function('system', prefix: '#include <stdlib.h>'))
 config_host_data.set('HAVE_HOST_BLOCK_DEVICE', have_host_block_device)
+config_host_data.set('HAVE_SYS_DISK_H', cc.has_header('sys/disk.h'))
 
 config_host_data.set('CONFIG_PREADV', cc.has_function('preadv', prefix: '#include <sys/uio.h>'))
 
-- 
2.31.1

[PATCH 5/5] block: detect DKIOCGETBLOCKCOUNT/SIZE before use

[Paolo Bonzini]

From: Joelle van Dyne <j@getutm.app>

iOS hosts do not have these defined so we fallback to the
default behaviour.

Co-authored-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Joelle van Dyne <j@getutm.app>
Message-Id: <20210315180341.31638-4-j@getutm.app>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/file-posix.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index e83f34a960..34bd413553 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2311,8 +2311,11 @@ static int64_t raw_getlength(BlockDriverState *bs)
 again:
 #endif
     if (!fstat(fd, &sb) && (S_IFCHR & sb.st_mode)) {
+        size = 0;
 #ifdef DIOCGMEDIASIZE
-        if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size))
+        if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size)) {
+            size = 0;
+        }
 #elif defined(DIOCGPART)
         {
                 struct partinfo pi;
@@ -2321,9 +2324,7 @@ again:
                 else
                         size = 0;
         }
-        if (size == 0)
-#endif
-#if defined(__APPLE__) && defined(__MACH__)
+#elif defined(DKIOCGETBLOCKCOUNT) && defined(DKIOCGETBLOCKSIZE)
         {
             uint64_t sectors = 0;
             uint32_t sector_size = 0;
@@ -2331,19 +2332,15 @@ again:
             if (ioctl(fd, DKIOCGETBLOCKCOUNT, &sectors) == 0
                && ioctl(fd, DKIOCGETBLOCKSIZE, &sector_size) == 0) {
                 size = sectors * sector_size;
-            } else {
-                size = lseek(fd, 0LL, SEEK_END);
-                if (size < 0) {
-                    return -errno;
-                }
             }
         }
-#else
-        size = lseek(fd, 0LL, SEEK_END);
+#endif
+        if (size == 0) {
+            size = lseek(fd, 0LL, SEEK_END);
+        }
         if (size < 0) {
             return -errno;
         }
-#endif
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
         switch(s->type) {
         case FTYPE_CD:
-- 
2.31.1

Re: [PATCH 0/5] block: file-posix queue

[Kevin Wolf]

Am 18.05.2021 um 10:38 hat Paolo Bonzini geschrieben:
> Hi Max/Kevin,
> 
> this is a combination of two series that both affect host block device
> support in block/file-posix.c.  I suspect both of them evaded your radar,
> so I'm grouping them together and sending them out again.

Is this based on any other series? The first two patches seem to fail to
apply, on my block branch as well as on master.

Kevin

Re: [PATCH 0/5] block: file-posix queue

[Paolo Bonzini]

On 18/05/21 15:23, Kevin Wolf wrote:
> Am 18.05.2021 um 10:38 hat Paolo Bonzini geschrieben:
>> Hi Max/Kevin,
>>
>> this is a combination of two series that both affect host block device
>> support in block/file-posix.c.  I suspect both of them evaded your radar,
>> so I'm grouping them together and sending them out again.
> 
> Is this based on any other series? The first two patches seem to fail to
> apply, on my block branch as well as on master.

It should have been six patches not five.  I'll resend.

Paolo