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Message-Id: <20201023112659.1559-1-artem.blagodarenko@gmail.com>
Date: Fri, 23 Oct 2020 07:26:59 -0400
From: Artem Blagodarenko <artem.blagodarenko@...il.com>
To: linux-ext4@...r.kernel.org
Cc: adilger.kernel@...ger.ca, Alexey Lyashkov <alexey.lyashkov@....com>
Subject: [PATCH] libfs: Fix DIO mode aligment
From: Alexey Lyashkov <alexey.lyashkov@....com>
Bounce buffer must be extended to hold a whole disk block size.
Read/write operations with unaligned offsets is prohobined
in the DIO mode, so read/write blocks should be adjusted to
reflect it.
Change-Id: Ic573c9ff0d476028dd2293f8b814c6112705db0e
Signed-off-by: Alexey Lyashkov <alexey.lyashkov@....com>
HPE-bug-id: LUS-9241
---
lib/ext2fs/io_manager.c | 5 +-
lib/ext2fs/unix_io.c | 296 +++++++++++++++++++++++++---------------
2 files changed, 190 insertions(+), 111 deletions(-)
diff --git a/lib/ext2fs/io_manager.c b/lib/ext2fs/io_manager.c
index c395d615..84399a12 100644
--- a/lib/ext2fs/io_manager.c
+++ b/lib/ext2fs/io_manager.c
@@ -20,6 +20,9 @@
#include "ext2_fs.h"
#include "ext2fs.h"
+#define max(a, b) ((a) > (b) ? (a) : (b))
+
+
errcode_t io_channel_set_options(io_channel channel, const char *opts)
{
errcode_t retval = 0;
@@ -128,7 +131,7 @@ errcode_t io_channel_alloc_buf(io_channel io, int count, void *ptr)
size_t size;
if (count == 0)
- size = io->block_size;
+ size = max(io->block_size, io->align);
else if (count > 0)
size = io->block_size * count;
else
diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
index 628e60c3..53647a22 100644
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -154,46 +154,30 @@ static char *safe_getenv(const char *arg)
/*
* Here are the raw I/O functions
*/
-static errcode_t raw_read_blk(io_channel channel,
+static errcode_t raw_aligned_read_blk(io_channel channel,
struct unix_private_data *data,
- unsigned long long block,
- int count, void *bufv)
+ ext2_loff_t location,
+ ssize_t size, void *bufv,
+ int *asize)
{
- errcode_t retval;
- ssize_t size;
- ext2_loff_t location;
int actual = 0;
+ errcode_t retval;
unsigned char *buf = bufv;
- ssize_t really_read = 0;
-
- size = (count < 0) ? -count : (ext2_loff_t) count * channel->block_size;
- data->io_stats.bytes_read += size;
- location = ((ext2_loff_t) block * channel->block_size) + data->offset;
- if (data->flags & IO_FLAG_FORCE_BOUNCE) {
- if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
- retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
- goto error_out;
- }
- goto bounce_read;
- }
+#ifdef ALIGN_DEBUG
+ printf("raw_aligned_read_blk: %p %lu<>%lu\n", buf,
+ location, (unsigned long) size);
+#endif
#ifdef HAVE_PREAD64
/* Try an aligned pread */
- if ((channel->align == 0) ||
- (IS_ALIGNED(buf, channel->align) &&
- IS_ALIGNED(size, channel->align))) {
- actual = pread64(data->dev, buf, size, location);
- if (actual == size)
- return 0;
- actual = 0;
- }
+ actual = pread64(data->dev, buf, size, location);
+ if (actual == size)
+ return 0;
+ actual = 0;
#elif HAVE_PREAD
/* Try an aligned pread */
- if ((sizeof(off_t) >= sizeof(ext2_loff_t)) &&
- ((channel->align == 0) ||
- (IS_ALIGNED(buf, channel->align) &&
- IS_ALIGNED(size, channel->align)))) {
+ if (sizeof(off_t) >= sizeof(ext2_loff_t)) {
actual = pread(data->dev, buf, size, location);
if (actual == size)
return 0;
@@ -205,47 +189,100 @@ static errcode_t raw_read_blk(io_channel channel,
retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
goto error_out;
}
+
+ actual = read(data->dev, buf, size);
+ if (actual != size) {
+ if (actual < 0) {
+ retval = errno;
+ actual = 0;
+ } else {
+ retval = EXT2_ET_SHORT_READ;
+ }
+ }
+
+error_out:
+ *asize = actual;
+ return retval;
+}
+
+
+/*
+ * Here are the raw I/O functions
+ */
+static errcode_t raw_read_blk(io_channel channel,
+ struct unix_private_data *data,
+ unsigned long long block,
+ int count, void *bufv)
+{
+ errcode_t retval;
+ ssize_t size;
+ ext2_loff_t location;
+ int actual = 0;
+ unsigned char *buf = bufv;
+ unsigned int align = channel->align;
+ ssize_t really_read = 0;
+ blk64_t blk;
+ loff_t offset;
+
+ size = (count < 0) ? -count : count * channel->block_size;
+ data->io_stats.bytes_read += size;
+ location = ((ext2_loff_t) block * channel->block_size) + data->offset;
+
+ if (data->flags & IO_FLAG_FORCE_BOUNCE) {
+ align = channel->block_size;
+ goto bounce_read;
+ }
+
if ((channel->align == 0) ||
- (IS_ALIGNED(buf, channel->align) &&
+ (IS_ALIGNED(location, channel->align) &&
+ IS_ALIGNED(buf, channel->align) &&
IS_ALIGNED(size, channel->align))) {
- actual = read(data->dev, buf, size);
- if (actual != size) {
- short_read:
- if (actual < 0) {
- retval = errno;
- actual = 0;
- } else
- retval = EXT2_ET_SHORT_READ;
+ retval = raw_aligned_read_blk(channel, data, location,
+ size, bufv, &actual);
+ if (retval != 0)
goto error_out;
- }
- return 0;
+
+ return retval;
}
+bounce_read:
#ifdef ALIGN_DEBUG
- printf("raw_read_blk: O_DIRECT fallback: %p %lu\n", buf,
- (unsigned long) size);
+ printf("raw_read_blk: O_DIRECT fallback: %p %lu<>%lu\n", buf,
+ location, (unsigned long) size);
#endif
-
/*
* The buffer or size which we're trying to read isn't aligned
* to the O_DIRECT rules, so we need to do this the hard way...
+ * read / write must be aligned to the block device sector size
*/
-bounce_read:
+
+ blk = location / align;
+ offset = location % align;
+
+ if (lseek(data->dev, blk * align, SEEK_SET) < 0)
+ return errno;
+
while (size > 0) {
- actual = read(data->dev, data->bounce, channel->block_size);
- if (actual != channel->block_size) {
+ actual = read(data->dev, data->bounce, align);
+ if (actual != align) {
actual = really_read;
buf -= really_read;
size += really_read;
- goto short_read;
+ retval = EXT2_ET_SHORT_READ;
+ goto error_out;
}
actual = size;
- if (size > channel->block_size)
- actual = channel->block_size;
- memcpy(buf, data->bounce, actual);
+ if ((actual + offset) > align)
+ actual = align - offset;
+ if (actual > size)
+ actual = size;
+
+ memcpy(buf, data->bounce + offset, actual);
really_read += actual;
size -= actual;
buf += actual;
+ offset = 0;
+ blk++;
}
return 0;
@@ -258,6 +295,58 @@ error_out:
return retval;
}
+static errcode_t raw_aligned_write_blk(io_channel channel,
+ struct unix_private_data *data,
+ ext2_loff_t location,
+ ssize_t size, const void *bufv,
+ int *asize)
+
+{
+ int actual = 0;
+ errcode_t retval;
+ const unsigned char *buf = (void *)bufv;
+
+#ifdef ALIGN_DEBUG
+ printf("raw_aligned_write_blk: %p %lu %lu\n", buf,
+ location, (unsigned long) size);
+#endif
+
+#ifdef HAVE_PWRITE64
+ /* Try an aligned pwrite */
+ actual = pwrite64(data->dev, buf, size, location);
+ if (actual == size)
+ return 0;
+#elif HAVE_PWRITE
+ /* Try an aligned pwrite */
+ if ((sizeof(off_t) >= sizeof(ext2_loff_t)) {
+ actual = pwrite(data->dev, buf, size, location);
+ if (actual == size)
+ return 0;
+ }
+#endif /* HAVE_PWRITE */
+
+ if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+
+ actual = write(data->dev, buf, size);
+ if (actual < 0) {
+ retval = errno;
+ goto error_out;
+ }
+ if (actual != size) {
+ retval = EXT2_ET_SHORT_WRITE;
+ goto error_out;
+ }
+ retval = 0;
+error_out:
+ *asize = actual;
+ return retval;
+
+}
+
+
static errcode_t raw_write_blk(io_channel channel,
struct unix_private_data *data,
unsigned long long block,
@@ -268,6 +357,9 @@ static errcode_t raw_write_blk(io_channel channel,
int actual = 0;
errcode_t retval;
const unsigned char *buf = bufv;
+ unsigned int align = channel->align;
+ blk64_t blk;
+ loff_t offset;
if (count == 1)
size = channel->block_size;
@@ -282,95 +374,79 @@ static errcode_t raw_write_blk(io_channel channel,
location = ((ext2_loff_t) block * channel->block_size) + data->offset;
if (data->flags & IO_FLAG_FORCE_BOUNCE) {
- if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
- retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
- goto error_out;
- }
+ align = channel->block_size;
goto bounce_write;
}
-#ifdef HAVE_PWRITE64
- /* Try an aligned pwrite */
if ((channel->align == 0) ||
- (IS_ALIGNED(buf, channel->align) &&
+ (IS_ALIGNED(location, channel->align) &&
+ IS_ALIGNED(buf, channel->align) &&
IS_ALIGNED(size, channel->align))) {
- actual = pwrite64(data->dev, buf, size, location);
- if (actual == size)
- return 0;
- }
-#elif HAVE_PWRITE
- /* Try an aligned pwrite */
- if ((sizeof(off_t) >= sizeof(ext2_loff_t)) &&
- ((channel->align == 0) ||
- (IS_ALIGNED(buf, channel->align) &&
- IS_ALIGNED(size, channel->align)))) {
- actual = pwrite(data->dev, buf, size, location);
- if (actual == size)
- return 0;
- }
-#endif /* HAVE_PWRITE */
+ retval = raw_aligned_write_blk(channel, data, location,
+ size, bufv, &actual);
+ if (retval != 0)
+ goto error_out;
- if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
- retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
- goto error_out;
+ return retval;
}
- if ((channel->align == 0) ||
- (IS_ALIGNED(buf, channel->align) &&
- IS_ALIGNED(size, channel->align))) {
- actual = write(data->dev, buf, size);
- if (actual < 0) {
- retval = errno;
- goto error_out;
- }
- if (actual != size) {
- short_write:
- retval = EXT2_ET_SHORT_WRITE;
- goto error_out;
- }
- return 0;
- }
+bounce_write:
#ifdef ALIGN_DEBUG
printf("raw_write_blk: O_DIRECT fallback: %p %lu\n", buf,
(unsigned long) size);
#endif
+
+ /* logical offset may don't aligned with block device block size */
+ blk = location / align;
+ offset = location % align;
+
+ if (lseek(data->dev, blk * align, SEEK_SET) != blk * align) {
+ retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
+ goto error_out;
+ }
+
/*
* The buffer or size which we're trying to write isn't aligned
* to the O_DIRECT rules, so we need to do this the hard way...
*/
-bounce_write:
while (size > 0) {
- if (size < channel->block_size) {
- actual = read(data->dev, data->bounce,
- channel->block_size);
- if (actual != channel->block_size) {
- if (actual < 0) {
- retval = errno;
- goto error_out;
- }
- memset((char *) data->bounce + actual, 0,
- channel->block_size - actual);
+ int actual_w;
+
+ memset((char *) data->bounce, 0, align);
+ if (offset || (size < align)) {
+ actual = read(data->dev, data->bounce, align);
+ if (actual < 0) {
+ retval = errno;
+ goto error_out;
}
}
actual = size;
- if (size > channel->block_size)
- actual = channel->block_size;
- memcpy(data->bounce, buf, actual);
- if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
+ if ((actual + offset) > align)
+ actual = align - offset;
+ if (actual > size)
+ actual = size;
+ memcpy(((char *)data->bounce) + offset, buf, actual);
+
+ if (lseek(data->dev, blk * align, SEEK_SET) != blk * align) {
retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
goto error_out;
}
- actual = write(data->dev, data->bounce, channel->block_size);
- if (actual < 0) {
+
+ actual_w = write(data->dev, data->bounce, align);
+ if (actual_w < 0) {
retval = errno;
goto error_out;
}
- if (actual != channel->block_size)
- goto short_write;
+ if (actual_w != align) {
+ retval = EXT2_ET_SHORT_WRITE;
+ goto error_out;
+ }
size -= actual;
buf += actual;
location += actual;
+ blk ++;
+ offset = 0;
}
return 0;
--
2.18.4
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