# Start fixing the problems with aligned access to COW files when O_DIRECT
# is enabled.
Index: linux-2.6.17/arch/um/drivers/ubd_kern.c
===================================================================
--- linux-2.6.17.orig/arch/um/drivers/ubd_kern.c 2007-11-19 11:31:55.000000000 -0500
+++ linux-2.6.17/arch/um/drivers/ubd_kern.c 2007-11-19 11:31:59.000000000 -0500
@@ -121,10 +121,10 @@ static struct gendisk *fake_gendisk[MAX_
#ifdef CONFIG_BLK_DEV_UBD_SYNC
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 1, .c = 0, \
- .cl = 1 })
+ .cl = 1, .d = 1 })
#else
#define OPEN_FLAGS ((struct openflags) { .r = 1, .w = 1, .s = 0, .c = 0, \
- .cl = 1 })
+ .cl = 1, .d = 1 })
#endif
static struct openflags global_openflags = OPEN_FLAGS;
@@ -149,6 +149,7 @@ struct ubd {
int count;
int fd;
__u64 size;
+ int io_unit;
struct openflags boot_openflags;
struct openflags openflags;
unsigned shared:1;
@@ -176,6 +177,7 @@ struct ubd {
.count = 0, \
.fd = -1, \
.size = -1, \
+ .io_unit = 1, \
.boot_openflags = OPEN_FLAGS, \
.openflags = OPEN_FLAGS, \
.no_cow = 0, \
@@ -930,6 +932,10 @@ static int ubd_add(int n, char **error_o
ubd_dev->queue->queuedata = ubd_dev;
blk_queue_max_hw_segments(ubd_dev->queue, MAX_SG);
+ if(doing_aio()){
+ ubd_dev->io_unit = PAGE_SIZE;
+ blk_queue_hardsect_size(ubd_dev->queue, PAGE_SIZE);
+ }
err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]);
if(err){
*error_out = "Failed to register device";
@@ -1468,6 +1474,13 @@ int open_ubd_file(char *file, struct ope
if(backing_file_out == NULL)
return fd;
+ err = os_set_fd_odirect(fd, 0);
+ if(err){
+ printk("Failed to disable O_DIRECT on COW file, err = %d\n",
+ err);
+ goto out_close;
+ }
+
err = read_cow_header(file_reader, &fd, &version, &backing_file, &mtime,
&size, §orsize, &align, bitmap_offset_out);
if(err && (*backing_file_out != NULL)){
@@ -1475,9 +1488,21 @@ int open_ubd_file(char *file, struct ope
"errno = %d\n", file, -err);
goto out_close;
}
+
+
+ /* XXX Don't know what case this is covering - it short-circuits
+ * re-enabling O_DIRECT below.
+ */
if(err)
return fd;
+ err = os_set_fd_odirect(fd, openflags->d);
+ if(err){
+ printk("Failed to maybe enable O_DIRECT on COW file, "
+ "err = %d\n", err);
+ goto out_close;
+ }
+
asked_switch = path_requires_switch(*backing_file_out, backing_file, file);
/* Allow switching only if no mismatch. */
@@ -1569,7 +1594,7 @@ static int do_io(struct io_thread_req *r
struct bitmap_io *bitmap_io = NULL;
char *buf, *bits;
unsigned long len, sector, start, *bitmap = dev->cow.bitmap;
- int nsectors, end, bit, err;
+ int nsectors, end, bit, err, io_bits;
__u64 off;
if(req->bitmap_start != -1){
@@ -1577,8 +1602,13 @@ static int do_io(struct io_thread_req *r
if(IS_ERR(bitmap_io))
return PTR_ERR(bitmap_io);
- off = req->bitmap_start / 8;
- len = (req->bitmap_end - 8 * off + 8 - 1) / 8;
+ io_bits = 8 * dev->io_unit;
+ off = req->bitmap_start / io_bits;
+ off *= dev->io_unit;
+
+ len = (req->bitmap_end - 8 * off + io_bits - 1) / io_bits;
+ len *= dev->io_unit;
+
bits = &((char *) bitmap)[off];
*bitmap_io = ((struct bitmap_io)
Index: linux-2.6.17/arch/um/include/os.h
===================================================================
--- linux-2.6.17.orig/arch/um/include/os.h 2007-11-19 10:53:25.000000000 -0500
+++ linux-2.6.17/arch/um/include/os.h 2007-11-19 11:31:59.000000000 -0500
@@ -150,6 +150,7 @@ extern int os_ioctl_generic(int fd, unsi
extern int os_get_ifname(int fd, char *namebuf);
extern int os_set_slip(int fd);
extern int os_set_owner(int fd, int pid);
+extern int os_set_fd_odirect(int fd, int odirect);
extern int os_mode_fd(int fd, int mode);
extern int os_seek_file(int fd, unsigned long long offset);
Index: linux-2.6.17/arch/um/os-Linux/file.c
===================================================================
--- linux-2.6.17.orig/arch/um/os-Linux/file.c 2007-11-19 11:31:53.000000000 -0500
+++ linux-2.6.17/arch/um/os-Linux/file.c 2007-11-19 11:31:59.000000000 -0500
@@ -187,6 +187,27 @@ int os_set_owner(int fd, int pid)
return 0;
}
+extern int os_set_fd_odirect(int fd, int odirect)
+{
+ int err, flags;
+
+ flags = fcntl(fd, F_GETFL);
+ if(flags < 0)
+ return -errno;
+
+ if(((flags & O_DIRECT) != 0) == odirect)
+ return 0;
+
+ if(odirect)
+ flags |= O_DIRECT;
+ else flags &= ~O_DIRECT;
+
+ err = fcntl(fd, F_SETFL, flags);
+ if(err)
+ return err;
+ return 0;
+}
+
int os_mode_fd(int fd, int mode)
{
int err;
@@ -259,6 +280,7 @@ int os_open_file(char *file, struct open
if(flags.c) f |= O_CREAT;
if(flags.t) f |= O_TRUNC;
if(flags.e) f |= O_EXCL;
+ if(flags.d) f |= O_DIRECT;
fd = open64(file, f, mode);
if(fd < 0)
Index: linux-2.6.17/arch/um/include/aio.h
===================================================================
--- linux-2.6.17.orig/arch/um/include/aio.h 2007-11-19 11:25:47.000000000 -0500
+++ linux-2.6.17/arch/um/include/aio.h 2007-11-19 11:31:59.000000000 -0500
@@ -27,6 +27,7 @@ struct aio_context {
.driver = aio_driver, \
.next = NULL }
+extern int doing_aio(void);
extern int submit_aio(struct aio_context *aio);
extern int finish_aio(void);
Index: linux-2.6.17/arch/um/os-Linux/aio.c
===================================================================
--- linux-2.6.17.orig/arch/um/os-Linux/aio.c 2007-11-19 11:30:14.000000000 -0500
+++ linux-2.6.17/arch/um/os-Linux/aio.c 2007-11-19 11:32:27.000000000 -0500
@@ -430,6 +430,11 @@ static int init_aio(void)
return 0;
}
+int doing_aio(void)
+{
+ return(!aio_24);
+}
+
/*
* The reason for the __initcall/__uml_exitcall asymmetry is that init_aio
* needs to be called when the kernel is running because it calls run_helper,