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Message-ID: <20101123151707.GC32759@thunk.org>
Date: Tue, 23 Nov 2010 10:17:07 -0500
From: Ted Ts'o <tytso@....edu>
To: Lukas Czerner <lczerner@...hat.com>
Cc: sandeen@...hat.com, adilger@...ger.ca, linux-ext4@...r.kernel.org
Subject: Re: [3/6] e2fsck: Discard free data and inode blocks.
On Thu, Nov 18, 2010 at 03:38:38AM -0000, Lukas Czerner wrote:
> In Pass 5 when we are checking block and inode bitmaps we have great
> opportunity to discard free space and unused inodes on the device,
> because bitmaps has just been verified as valid. This commit takes
> advantage of this opportunity and discards both, all free space and
> unused inodes.
>
> I have added new set of options, 'nodiscard' and 'discard'. When the
> underlying devices does not support discard, or discard ends with an
> error, or when any kind of error occurs on the filesystem, no further
> discard attempt will be made and the e2fsck will behave as it would
> with nodiscard option provided.
Unfortunately, your patch set the ABORT flag and then returned an
error, which then cause pass 5 processing to stop. I've fixed in my
patches.
>
> As an addition, when there is any not-yet-zeroed inode table and
> discard zeroes data, then inode table is marked as zeroed.
>
> Signed-off-by: Lukas Czerner <lczerner@...hat.com>
- Ted
commit efa1a355a1e4142b2d057be06931eb8fc0903ba3
Author: Lukas Czerner <lczerner@...hat.com>
Date: Thu Nov 18 03:38:38 2010 +0000
e2fsck: Discard free data and inode blocks.
In Pass 5 when we are checking block and inode bitmaps we have great
opportunity to discard free space and unused inodes on the device,
because bitmaps has just been verified as valid. This commit takes
advantage of this opportunity and discards both, all free space and
unused inodes.
I have added new set of options, 'nodiscard' and 'discard'. When the
underlying devices does not support discard, or discard ends with an
error, or when any kind of error occurs on the filesystem, no further
discard attempt will be made and the e2fsck will behave as it would
with nodiscard option provided.
As an addition, when there is any not-yet-zeroed inode table and
discard zeroes data, then inode table is marked as zeroed.
Signed-off-by: Lukas Czerner <lczerner@...hat.com>
Signed-off-by: Theodore Ts'o <tytso@....edu>
diff --git a/e2fsck/e2fsck.8.in b/e2fsck/e2fsck.8.in
index 3fb15e6..4c2dd98 100644
--- a/e2fsck/e2fsck.8.in
+++ b/e2fsck/e2fsck.8.in
@@ -189,6 +189,20 @@ be 1 or 2. The default extended attribute version format is 2.
.BI fragcheck
During pass 1, print a detailed report of any discontiguous blocks for
files in the filesystem.
+.TP
+.BI discard
+Attempt to discard free blocks and unused inode blocks after the full
+filesystem check (discarding blocks is useful on solid state devices and sparse
+/ thin-provisioned storage). Note that discard is done in pass 5 AFTER the
+filesystem has been fully checked and only if it does not contain recognizable
+errors. However there might be cases where
+.B e2fsck
+does not fully recognise a problem and hence in this case this
+option may prevent you from further manual data recovery.
+.TP
+.BI nodiscard
+Do not attempt to discard free blocks and unused inode blocks. This option is
+exacly the opposite of discard option. This is set as default.
.RE
.TP
.B \-f
diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
index d4df5f3..a377246 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -155,6 +155,7 @@ struct resource_track {
#define E2F_OPT_WRITECHECK 0x0200
#define E2F_OPT_COMPRESS_DIRS 0x0400
#define E2F_OPT_FRAGCHECK 0x0800
+#define E2F_OPT_DISCARD 0x1000
/*
* E2fsck flags
diff --git a/e2fsck/pass5.c b/e2fsck/pass5.c
index cbc12f3..b423d28 100644
--- a/e2fsck/pass5.c
+++ b/e2fsck/pass5.c
@@ -10,9 +10,18 @@
*
*/
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <errno.h>
+
#include "e2fsck.h"
#include "problem.h"
+#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
+
static void check_block_bitmaps(e2fsck_t ctx);
static void check_inode_bitmaps(e2fsck_t ctx);
static void check_inode_end(e2fsck_t ctx);
@@ -64,6 +73,26 @@ void e2fsck_pass5(e2fsck_t ctx)
print_resource_track(ctx, _("Pass 5"), &rtrack, ctx->fs->io);
}
+static void e2fsck_discard_blocks(e2fsck_t ctx, io_manager manager,
+ blk64_t start, blk64_t count)
+{
+ ext2_filsys fs = ctx->fs;
+ int ret = 0;
+
+ /*
+ * If the filesystem has changed it means that there was an corruption
+ * which should be repaired, but in some cases just one e2fsck run is
+ * not enough to fix the problem, hence it is not safe to run discard
+ * in this case.
+ */
+ if (ext2fs_test_changed(ctx->fs))
+ ctx->options &= ~E2F_OPT_DISCARD;
+
+ if ((ctx->options & E2F_OPT_DISCARD) &&
+ (io_channel_discard(fs->io, start, count)))
+ ctx->options &= ~E2F_OPT_DISCARD;
+}
+
#define NO_BLK ((blk64_t) -1)
static void print_bitmap_problem(e2fsck_t ctx, int problem,
@@ -108,6 +137,7 @@ static void check_block_bitmaps(e2fsck_t ctx)
int group = 0;
int blocks = 0;
blk64_t free_blocks = 0;
+ blk64_t first_free = ext2fs_blocks_count(fs->super);
int group_free = 0;
int actual, bitmap;
struct problem_context pctx;
@@ -120,6 +150,7 @@ static void check_block_bitmaps(e2fsck_t ctx)
int cmp_block = 0;
int redo_flag = 0;
blk64_t super_blk, old_desc_blk, new_desc_blk;
+ io_manager manager = ctx->fs->io->manager;
clear_problem_context(&pctx);
free_array = (int *) e2fsck_allocate_memory(ctx,
@@ -281,10 +312,25 @@ redo_counts:
ctx->flags |= E2F_FLAG_PROG_SUPPRESS;
had_problem++;
+ /*
+ * If there a problem we should turn off the discard so we
+ * do not compromise the filesystem.
+ */
+ ctx->options &= ~E2F_OPT_DISCARD;
+
do_counts:
if (!bitmap && (!skip_group || csum_flag)) {
group_free++;
free_blocks++;
+ if (first_free > i)
+ first_free = i;
+ } else {
+ if ((i > first_free) &&
+ (ctx->options & E2F_OPT_DISCARD)) {
+ e2fsck_discard_blocks(ctx, manager, first_free,
+ (i - first_free));
+ }
+ first_free = ext2fs_blocks_count(fs->super);
}
blocks ++;
if ((blocks == fs->super->s_blocks_per_group) ||
@@ -381,6 +427,7 @@ static void check_inode_bitmaps(e2fsck_t ctx)
int csum_flag;
int skip_group = 0;
int redo_flag = 0;
+ io_manager manager = ctx->fs->io->manager;
clear_problem_context(&pctx);
free_array = (int *) e2fsck_allocate_memory(ctx,
@@ -500,6 +547,11 @@ redo_counts:
}
ctx->flags |= E2F_FLAG_PROG_SUPPRESS;
had_problem++;
+ /*
+ * If there a problem we should turn off the discard so we
+ * do not compromise the filesystem.
+ */
+ ctx->options &= ~E2F_OPT_DISCARD;
do_counts:
if (bitmap) {
@@ -509,11 +561,43 @@ do_counts:
group_free++;
free_inodes++;
}
+
inodes++;
if ((inodes == fs->super->s_inodes_per_group) ||
(i == fs->super->s_inodes_count)) {
+
free_array[group] = group_free;
dir_array[group] = dirs_count;
+
+ /* Discard inode table */
+ if (ctx->options & E2F_OPT_DISCARD) {
+ blk64_t used_blks, blk, num;
+
+ used_blks = DIV_ROUND_UP(
+ (EXT2_INODES_PER_GROUP(fs->super) -
+ group_free),
+ EXT2_INODES_PER_BLOCK(fs->super));
+
+ blk = ext2fs_inode_table_loc(fs, group) +
+ used_blks;
+ num = fs->inode_blocks_per_group -
+ used_blks;
+ e2fsck_discard_blocks(ctx, manager, blk, num);
+ }
+
+ /*
+ * If discard zeroes data and the group inode table
+ * was not zeroed yet, set itable as zeroed
+ */
+ if ((ctx->options & E2F_OPT_DISCARD) &&
+ (io_channel_discard_zeroes_data(fs->io)) &&
+ !(ext2fs_bg_flags_test(fs, group,
+ EXT2_BG_INODE_ZEROED))) {
+ ext2fs_bg_flags_set(fs, group,
+ EXT2_BG_INODE_ZEROED);
+ ext2fs_group_desc_csum_set(fs, group);
+ }
+
group ++;
inodes = 0;
skip_group = 0;
diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index 7eb269c..4cf55a9 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -594,6 +594,12 @@ static void parse_extended_opts(e2fsck_t ctx, const char *opts)
} else if (strcmp(token, "fragcheck") == 0) {
ctx->options |= E2F_OPT_FRAGCHECK;
continue;
+ } else if (strcmp(token, "discard") == 0) {
+ ctx->options |= E2F_OPT_DISCARD;
+ continue;
+ } else if (strcmp(token, "nodiscard") == 0) {
+ ctx->options &= ~E2F_OPT_DISCARD;
+ continue;
} else {
fprintf(stderr, _("Unknown extended option: %s\n"),
token);
@@ -609,6 +615,8 @@ static void parse_extended_opts(e2fsck_t ctx, const char *opts)
"Valid extended options are:\n"), stderr);
fputs(("\tea_ver=<ea_version (1 or 2)>\n"), stderr);
fputs(("\tfragcheck\n"), stderr);
+ fputs(("\tdiscard\n"), stderr);
+ fputs(("\tnodiscard\n"), stderr);
fputc('\n', stderr);
exit(1);
}
@@ -667,6 +675,7 @@ static errcode_t PRS(int argc, char *argv[], e2fsck_t *ret_ctx)
ctx->program_name = *argv;
else
ctx->program_name = "e2fsck";
+
while ((c = getopt (argc, argv, "panyrcC:B:dE:fvtFVM:b:I:j:P:l:L:N:SsDk")) != EOF)
switch (c) {
case 'C':
@@ -943,7 +952,6 @@ static errcode_t try_open_fs(e2fsck_t ctx, int flags, io_manager io_ptr,
return retval;
}
-
static const char *my_ver_string = E2FSPROGS_VERSION;
static const char *my_ver_date = E2FSPROGS_DATE;
diff --git a/lib/ext2fs/test_io.c b/lib/ext2fs/test_io.c
index 242d442..7da1ee6 100644
--- a/lib/ext2fs/test_io.c
+++ b/lib/ext2fs/test_io.c
@@ -509,7 +509,8 @@ static errcode_t test_discard(io_channel channel, unsigned long long block,
data = (struct test_private_data *) channel->private_data;
EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_TEST_IO_CHANNEL);
- retval = io_channel_discard(channel, block, count);
+ if (data->real)
+ retval = io_channel_discard(data->real, block, count);
if (data->flags & TEST_FLAG_DISCARD)
fprintf(data->outfile,
"Test_io: discard(%llu, %llu) returned %s\n",
--
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