From d66b197b227e1fbd4a72f002cb8b8a7ee9461062 Mon Sep 17 00:00:00 2001
From: "Brian C. Lane" <bcl@redhat.com>
Date: Thu, 6 Aug 2015 07:17:14 -0700
Subject: [PATCH 19/20] libparted: Use read only when probing devices on linux
(#1245144)
When a device is opened for RW closing it can trigger other actions,
like udev scanning it for partition changes. Use read only for the
init_* methods and RW for actual changes to the device.
This adds _device_open which takes mode flags as an argument and turns
linux_open into a wrapper for it with RW_MODE.
_device_open_ro is added to open the device with RD_MODE and increment
the open_counter. This is used in the init_* functions.
_device_close is a wrapper around linux_close that decrements the
open_counter and is used in the init_* functions.
All of these changes are self-contained with no external API changes.
The only visible change in behavior is that when a new PedDevice is
created the device is opened in RO_MODE instead of RW_MODE.
Resolves: rhbz#1245144
(cherry picked from commit 0e169215efcdb33d588ddc2267467593bbf717c9)
---
libparted/arch/linux.c | 62 +++++++++++++++++++++++++++++++++++---------------
1 file changed, 44 insertions(+), 18 deletions(-)
diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index b68130b..3934a5b 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -291,7 +291,9 @@ struct blkdev_ioctl_param {
static char* _device_get_part_path (PedDevice const *dev, int num);
static int _partition_is_mounted_by_path (const char* path);
static unsigned int _device_get_partition_range(PedDevice const* dev);
-
+static int _device_open (PedDevice* dev, int flags);
+static int _device_open_ro (PedDevice* dev);
+static int _device_close (PedDevice* dev);
static int
_read_fd (int fd, char **buf)
@@ -910,7 +912,7 @@ init_ide (PedDevice* dev)
if (!_device_stat (dev, &dev_stat))
goto error;
- if (!ped_device_open (dev))
+ if (!_device_open_ro (dev))
goto error;
if (ioctl (arch_specific->fd, HDIO_GET_IDENTITY, &hdi)) {
@@ -979,11 +981,11 @@ init_ide (PedDevice* dev)
if (!_device_probe_geometry (dev))
goto error_close_dev;
- ped_device_close (dev);
+ _device_close (dev);
return 1;
error_close_dev:
- ped_device_close (dev);
+ _device_close (dev);
error:
return 0;
}
@@ -1116,7 +1118,7 @@ init_scsi (PedDevice* dev)
char* vendor;
char* product;
- if (!ped_device_open (dev))
+ if (!_device_open_ro (dev))
goto error;
if (ioctl (arch_specific->fd, SCSI_IOCTL_GET_IDLUN, &idlun) < 0) {
@@ -1130,7 +1132,7 @@ init_scsi (PedDevice* dev)
goto error_close_dev;
if (!_device_probe_geometry (dev))
goto error_close_dev;
- ped_device_close (dev);
+ _device_close (dev);
return 1;
}
@@ -1152,11 +1154,11 @@ init_scsi (PedDevice* dev)
if (!_device_probe_geometry (dev))
goto error_close_dev;
- ped_device_close (dev);
+ _device_close (dev);
return 1;
error_close_dev:
- ped_device_close (dev);
+ _device_close (dev);
error:
return 0;
}
@@ -1168,7 +1170,7 @@ init_file (PedDevice* dev)
if (!_device_stat (dev, &dev_stat))
goto error;
- if (!ped_device_open (dev))
+ if (!_device_open_ro (dev))
goto error;
dev->sector_size = PED_SECTOR_SIZE_DEFAULT;
@@ -1195,7 +1197,7 @@ init_file (PedDevice* dev)
goto error_close_dev;
}
- ped_device_close (dev);
+ _device_close (dev);
dev->bios_geom.cylinders = dev->length / 4 / 32;
dev->bios_geom.heads = 4;
@@ -1206,7 +1208,7 @@ init_file (PedDevice* dev)
return 1;
error_close_dev:
- ped_device_close (dev);
+ _device_close (dev);
error:
return 0;
}
@@ -1222,7 +1224,7 @@ init_dasd (PedDevice* dev, const char* model_name)
if (!_device_stat (dev, &dev_stat))
goto error;
- if (!ped_device_open (dev))
+ if (!_device_open_ro (dev))
goto error;
LinuxSpecific* arch_specific = LINUX_SPECIFIC (dev);
@@ -1262,11 +1264,11 @@ init_dasd (PedDevice* dev, const char* model_name)
dev->model = strdup (model_name);
- ped_device_close (dev);
+ _device_close (dev);
return 1;
error_close_dev:
- ped_device_close (dev);
+ _device_close (dev);
error:
return 0;
}
@@ -1281,7 +1283,7 @@ init_generic (PedDevice* dev, const char* model_name)
if (!_device_stat (dev, &dev_stat))
goto error;
- if (!ped_device_open (dev))
+ if (!_device_open_ro (dev))
goto error;
ped_exception_fetch_all ();
@@ -1329,11 +1331,11 @@ init_generic (PedDevice* dev, const char* model_name)
dev->model = strdup (model_name);
- ped_device_close (dev);
+ _device_close (dev);
return 1;
error_close_dev:
- ped_device_close (dev);
+ _device_close (dev);
error:
return 0;
}
@@ -1620,12 +1622,27 @@ retry:
}
static int
+_device_open_ro (PedDevice* dev)
+{
+ int rc = _device_open (dev, RD_MODE);
+ if (rc)
+ dev->open_count++;
+ return rc;
+}
+
+static int
linux_open (PedDevice* dev)
{
+ return _device_open (dev, RW_MODE);
+}
+
+static int
+_device_open (PedDevice* dev, int flags)
+{
LinuxSpecific* arch_specific = LINUX_SPECIFIC (dev);
retry:
- arch_specific->fd = open (dev->path, RW_MODE);
+ arch_specific->fd = open (dev->path, flags);
if (arch_specific->fd == -1) {
char* rw_error_msg = strerror (errno);
@@ -1694,6 +1711,15 @@ linux_refresh_close (PedDevice* dev)
return 1;
}
+static int
+_device_close (PedDevice* dev)
+{
+ int rc = linux_close (dev);
+ if (dev->open_count > 0)
+ dev->open_count--;
+ return rc;
+}
+
#if SIZEOF_OFF_T < 8
static _syscall5(int,_llseek,
--
2.4.3