[lvm-devel] [PATCH 1/2] add dev_read2 support function
Dave Wysochanski
dwysocha at redhat.com
Tue Apr 17 17:23:51 UTC 2007
Add dev_read2 - read from 2 regions on the same device.
Should not change functional behavior.
Index: LVM2/lib/device/dev-io.c
===================================================================
--- LVM2.orig/lib/device/dev-io.c 2007-01-25 09:37:47.000000000 -0500
+++ LVM2/lib/device/dev-io.c 2007-04-17 12:34:49.000000000 -0400
@@ -564,6 +564,36 @@ int dev_read(struct device *dev, uint64_
return _aligned_io(&where, buffer, 0);
}
+/*
+ * Read from 'dev' into 'buf', possibly in 2 distinct regions, denoted
+ * by (offset,len) and (offset2,len2). Thus, the total size of
+ * 'buf' should be len+len2.
+ */
+int dev_read2(struct device *dev, uint64_t offset, size_t len,
+ uint64_t offset2, size_t len2, void *buf)
+{
+ if (!dev_read(dev, (uint64_t) offset, len, buf)) {
+ log_error("Read from %s failed", dev_name(dev));
+ stack;
+ return 0;
+ }
+
+ /*
+ * The second region is optional, and allows for
+ * a circular buffer on the device.
+ */
+ if (len2) {
+ if (!dev_read(dev, (uint64_t) offset2, len2,
+ buf + len)) {
+ log_error("Circular read from %s failed",
+ dev_name(dev));
+ stack;
+ return 0;
+ }
+ }
+ return 1;
+}
+
/* FIXME If O_DIRECT can't extend file, dev_extend first; dev_truncate after.
* But fails if concurrent processes writing
*/
Index: LVM2/lib/device/device.h
===================================================================
--- LVM2.orig/lib/device/device.h 2006-05-11 14:39:24.000000000 -0400
+++ LVM2/lib/device/device.h 2007-04-17 12:33:38.000000000 -0400
@@ -78,6 +78,8 @@ int dev_fd(struct device *dev);
const char *dev_name(const struct device *dev);
int dev_read(struct device *dev, uint64_t offset, size_t len, void *buffer);
+int dev_read2(struct device *dev, uint64_t offset, size_t len,
+ uint64_t offset2, size_t len2, void *buf);
int dev_write(struct device *dev, uint64_t offset, size_t len, void *buffer);
int dev_append(struct device *dev, size_t len, void *buffer);
int dev_set(struct device *dev, uint64_t offset, size_t len, int value);
Index: LVM2/lib/config/config.c
===================================================================
--- LVM2.orig/lib/config/config.c 2007-03-08 14:22:52.000000000 -0500
+++ LVM2/lib/config/config.c 2007-04-17 12:40:30.000000000 -0400
@@ -210,18 +210,10 @@ int read_config_fd(struct config_tree *c
stack;
return 0;
}
- if (!dev_read(dev, (uint64_t) offset, size, buf)) {
- log_error("Read from %s failed", dev_name(dev));
+ if (!dev_read2(dev, (uint64_t) offset, size,
+ (uint64_t) offset2, size2, buf)) {
goto out;
}
- if (size2) {
- if (!dev_read(dev, (uint64_t) offset2, size2,
- buf + size)) {
- log_error("Circular read from %s failed",
- dev_name(dev));
- goto out;
- }
- }
p->fb = buf;
}
Index: LVM2/WHATS_NEW
===================================================================
--- LVM2.orig/WHATS_NEW 2007-04-17 12:45:02.000000000 -0400
+++ LVM2/WHATS_NEW 2007-04-17 12:45:18.000000000 -0400
@@ -1,5 +1,6 @@
Version 2.02.25 -
=================================
+ Add dev_read2.
Add pvck command stub.
Update lists of attribute characters in man pages.
Change cling alloc policy attribute character from 'C' to l'.
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