On Wed, Jan 17, 2007 at 03:16:58PM +0530, Amit K. Arora wrote:
> The patches for e2fsprogs and fsx-linux are available with me. I can
> post them if anyone is interested to try/test the preallocation patches.
> Also, I have a small test program/tool written which can be used for
> unit testing.
Here is the patch to e2fsprogs-1.39, with patches for ext4 already
applied. It makes e2fsprogs tools recognize uninitialized extents. This
is only for testing purpose as of now and it might need some
fine-tuning, before it can be really be submitted.
This patch also enables "EXT_DEBUG" flag to display debug information
(e.g. extent details).
---
lib/ext2fs/bmap.c | 3 +-
lib/ext2fs/ext4_extents.h | 12 +++++++++-
lib/ext2fs/extents.c | 55 ++++++++++++++++++++++++++++------------------
3 files changed, 47 insertions(+), 23 deletions(-)
Index: e2fsprogs-1.39/lib/ext2fs/bmap.c
===================================================================
--- e2fsprogs-1.39.orig/lib/ext2fs/bmap.c 2006-12-19 11:53:48.000000000 +0530
+++ e2fsprogs-1.39/lib/ext2fs/bmap.c 2006-12-19 11:53:52.000000000 +0530
@@ -45,7 +45,8 @@
ex = EXT_FIRST_EXTENT(eh);
for (i = 0; i < eh->eh_entries; i++, ex++) {
if ((ex->ee_block <= block) &&
- (block < ex->ee_block + ex->ee_len)) {
+ (block < ex->ee_block +
+ ext4_ext_get_actual_len(ex))) {
*phys_blk = EXT4_EE_START(ex) +
(block - ex->ee_block);
return 0;
Index: e2fsprogs-1.39/lib/ext2fs/ext4_extents.h
===================================================================
--- e2fsprogs-1.39.orig/lib/ext2fs/ext4_extents.h 2006-12-19 11:53:48.000000000 +0530
+++ e2fsprogs-1.39/lib/ext2fs/ext4_extents.h 2006-12-19 15:55:32.000000000 +0530
@@ -37,7 +37,7 @@
* if EXT_DEBUG is defined you can use 'extdebug' mount option
* to get lots of info what's going on
*/
-//#define EXT_DEBUG
+#define EXT_DEBUG
#ifdef EXT_DEBUG
#define ext_debug(tree,fmt,a...) \
do { \
@@ -170,6 +170,16 @@
#define EXT_ASSERT(__x__) if (!(__x__)) BUG();
+/*
+ * Macro-instructions used to handle (mark/unmark/check/create) unitialized
+ * extents. Applications can issue an IOCTL for preallocation, which results
+ * in assigning unitialized extents to the file
+ */
+#define EXT4_CREATE_UNINITIALIZED_EXT 2
+#define ext4_ext_mark_uninitialized(ext) ((ext)->ee_len |= 0x8000)
+#define ext4_ext_is_uninitialized(ext) ((ext)->ee_len & 0x8000)
+#define ext4_ext_get_actual_len(ext) ((ext)->ee_len & 0x7FFF)
+
/*
* this structure is used to gather extents from the tree via ioctl
Index: e2fsprogs-1.39/lib/ext2fs/extents.c
===================================================================
--- e2fsprogs-1.39.orig/lib/ext2fs/extents.c 2006-12-19 11:53:48.000000000 +0530
+++ e2fsprogs-1.39/lib/ext2fs/extents.c 2006-12-19 11:55:03.000000000 +0530
@@ -36,9 +36,11 @@
void show_extent(struct ext4_extent *ex)
{
- printf("extent: block=%u-%u len=%u start=%u start_hi=%u\n",
- ex->ee_block, ex->ee_block + ex->ee_len - 1,
- ex->ee_len, ex->ee_start, ex->ee_start_hi);
+ unsigned short ee_len = ext4_ext_get_actual_len(ex);
+ printf("extent[%c]: block=%u-%u len=%u start=%u start_hi=%u\n",
+ ext4_ext_is_uninitialized(ex) ? 'u' : 'i',
+ ex->ee_block, ex->ee_block + ee_len - 1, ee_len,
+ ex->ee_start, ex->ee_start_hi);
}
#else
#define show_header(eh) do { } while (0)
@@ -75,7 +77,7 @@
if (EXT4_EE_START(ex) > EXT2_BLOCKS_COUNT(fs->super))
return EXT2_ET_EXTENT_LEAF_BAD;
- if (ex->ee_len == 0)
+ if (ext4_ext_get_actual_len(ex) == 0)
return EXT2_ET_EXTENT_LEAF_BAD;
if (ex_prev) {
@@ -84,13 +86,14 @@
return EXT2_ET_EXTENT_LEAF_BAD;
/* extents must be in logical offset order */
- if (ex->ee_block < ex_prev->ee_block + ex_prev->ee_len)
+ if (ex->ee_block < ex_prev->ee_block +
+ ext4_ext_get_actual_len(ex_prev))
return EXT2_ET_EXTENT_LEAF_BAD;
/* extents must not overlap physical blocks */
- if ((EXT4_EE_START(ex) <
- EXT4_EE_START(ex_prev) + ex_prev->ee_len) &&
- (EXT4_EE_START(ex) + ex->ee_len > EXT4_EE_START(ex_prev)))
+ if ((EXT4_EE_START(ex) < EXT4_EE_START(ex_prev) +
+ ext4_ext_get_actual_len(ex_prev)) && (EXT4_EE_START(ex)
+ + ext4_ext_get_actual_len(ex) > EXT4_EE_START(ex_prev)))
return EXT2_ET_EXTENT_LEAF_BAD;
}
@@ -98,7 +101,8 @@
if (ex->ee_block < ix->ei_block)
return EXT2_ET_EXTENT_LEAF_BAD;
- if (ix_len && ex->ee_block + ex->ee_len > ix->ei_block + ix_len)
+ if (ix_len && ex->ee_block + ext4_ext_get_actual_len(ex) >
+ ix->ei_block + ix_len)
return EXT2_ET_EXTENT_LEAF_BAD;
}
@@ -144,6 +148,7 @@
{
int entry = ex - EXT_FIRST_EXTENT(eh);
struct ext4_extent *ex_new = ex + 1;
+ unsigned uninitialized=0;
if (entry < 0 || entry > eh->eh_entries)
return EXT2_ET_EXTENT_LEAF_BAD;
@@ -151,18 +156,25 @@
if (eh->eh_entries >= eh->eh_max)
return EXT2_ET_EXTENT_NO_SPACE;
- if (count > ex->ee_len)
+ if (count > ext4_ext_get_actual_len(ex))
return EXT2_ET_EXTENT_LEAF_BAD;
- if (count > ex->ee_len)
+ if (count > ext4_ext_get_actual_len(ex))
return EXT2_ET_EXTENT_LEAF_BAD;
+ if(ext4_ext_is_uninitialized(ex))
+ uninitialized=1;
+
memmove(ex_new, ex, (eh->eh_entries - entry) * sizeof(*ex));
++eh->eh_entries;
ex->ee_len = count;
ex_new->ee_len -= count;
ex_new->ee_block += count;
+ if(uninitialized) {
+ ext4_ext_mark_uninitialized(ex);
+ ext4_ext_mark_uninitialized(ex_new);
+ }
EXT4_EE_START_SET(ex_new, EXT4_EE_START(ex_new) + count);
return 0;
@@ -195,7 +207,7 @@
ex = EXT_FIRST_EXTENT(eh);
for (i = 0; i < eh->eh_entries; i++, ex++) {
show_extent(ex);
- for (j = 0; j < ex->ee_len; j++) {
+ for (j = 0; j < ext4_ext_get_actual_len(ex); j++) {
block_address = EXT4_EE_START(ex) + j;
flags = (*ctx->func)(ctx->fs, &block_address,
(ex->ee_block + j),
@@ -216,15 +228,15 @@
#endif
if (ex_prev &&
- block_address ==
- EXT4_EE_START(ex_prev) + ex_prev->ee_len &&
- ex->ee_block + j ==
- ex_prev->ee_block + ex_prev->ee_len) {
+ block_address == EXT4_EE_START(ex_prev) +
+ ext4_ext_get_actual_len(ex_prev) &&
+ ex->ee_block + j == ex_prev->ee_block +
+ ext4_ext_get_actual_len(ex_prev)) {
/* can merge block with prev extent */
ex_prev->ee_len++;
ex->ee_len--;
- if (ex->ee_len == 0) {
+ if (ext4_ext_get_actual_len(ex) == 0) {
/* no blocks left in this one */
ext2fs_extent_remove(eh, ex);
i--; ex--;
@@ -238,7 +250,7 @@
}
ret |= BLOCK_CHANGED;
- } else if (ex->ee_len == 1) {
+ } else if (ext4_ext_get_actual_len(ex) == 1) {
/* single-block extent is easy -
* change extent directly */
EXT4_EE_START_SET(ex, block_address);
@@ -250,7 +262,8 @@
ret |= BLOCK_ABORT | BLOCK_ERROR;
return ret;
- } else if (j > 0 && (ex + 1)->ee_len > 1 &&
+ } else if (j > 0 &&
+ ext4_ext_get_actual_len(ex + 1) > 1 &&
ext2fs_extent_split(eh, ex + 1, 1)) {
/* split after new block failed */
/* No multi-level split yet */
@@ -258,7 +271,7 @@
return ret;
} else if (j == 0) {
- if (ex->ee_len != 1) {
+ if (ext4_ext_get_actual_len(ex) != 1) {
/* this is an internal error */
ret |= BLOCK_ABORT |BLOCK_ERROR;
return ret;
@@ -269,7 +282,7 @@
} else {
ex++;
i++;
- if (ex->ee_len != 1) {
+ if (ext4_ext_get_actual_len(ex) != 1) {
/* this is an internal error */
ret |= BLOCK_ABORT |BLOCK_ERROR;
return ret;
--
Regards,
Amit Arora
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