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Date: Tue, 16 Jul 2013 18:24:50 +0400
From: Dmitry Monakhov <dmonakhov@...nvz.org>
To: Theodore Ts'o <tytso@....edu>, Eric Sandeen <sandeen@...hat.com>
Cc: David Jeffery <djeffery@...hat.com>, linux-ext4@...r.kernel.org
Subject: Re: [PATCH] e2fsck: detect invalid extents at the end of an extent-block
On Thu, 6 Jun 2013 23:39:34 -0400, Theodore Ts'o <tytso@....edu> wrote:
> Thanks for the review. I took your changes, and added a bit more code
> cleanup.
>
> Here's the version I ultimately checked into my tree.
This patch cause regression
TESTCASE:
#!/bin/bash
IMG=./IMG
MNT=/mnt
dd if=/dev/zero of=$IMG bs=1M count=16
mkfs.ext4 -b4096 -F $IMG
mount $IMG $MNT -oloop || exit 1
fallocate -n -l $((1024*1024*2)) $MNT/f1
for ((i=0;i<4;i++))
do
dd if=/dev/zero of=$MNT/f1 bs=4k count=1 seek=$((i*100)) conv=notrunc
done
sync
filefrag -v $MNT/f1
umount $MNT
e2fsck -f -n $IMG
>
> - Ted
>
> commit d3f32c2db8f11c87aa7939d78e7eb4c373f7034f
> Author: David Jeffery <djeffery@...hat.com>
> Date: Thu Jun 6 20:04:33 2013 -0400
>
> e2fsck: detect invalid extents at the end of an extent-block
>
> e2fsck does not detect extents which are outside their location in the
> extent tree. This can result in a bad extent at the end of an extent-block
> not being detected.
>
> From a part of a dump_extents output:
>
> 1/ 2 37/ 68 143960 - 146679 123826181 2720
> 2/ 2 1/ 2 143960 - 146679 123785816 - 123788535 2720
> 2/ 2 2/ 2 146680 - 147583 123788536 - 123789439 904 Uninit <-bad extent
> 1/ 2 38/ 68 146680 - 149391 123826182 2712
> 2/ 2 1/ 2 146680 - 147583 18486 - 19389 904
> 2/ 2 2/ 2 147584 - 149391 123789440 - 123791247 1808
>
> e2fsck does not detect this bad extent which both overlaps another, valid
> extent, and is invalid by being beyond the end of the extent above it in
> the tree.
>
> This patch modifies e2fsck to detect this invalid extent and remove it.
>
> Signed-off-by: David Jeffery <djeffery@...hat.com>
> Signed-off-by: Theodore Ts'o <tytso@....edu>
> Reviewed-by: Eric Sandeen <sandeen@...hat.com>
>
> diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
> index de00638..af9afe3 100644
> --- a/e2fsck/pass1.c
> +++ b/e2fsck/pass1.c
> @@ -1760,11 +1760,11 @@ void e2fsck_clear_inode(e2fsck_t ctx, ext2_ino_t ino,
>
> static void scan_extent_node(e2fsck_t ctx, struct problem_context *pctx,
> struct process_block_struct *pb,
> - blk64_t start_block,
> + blk64_t start_block, blk64_t end_block,
> ext2_extent_handle_t ehandle)
> {
> struct ext2fs_extent extent;
> - blk64_t blk;
> + blk64_t blk, last_lblk;
> e2_blkcnt_t blockcnt;
> unsigned int i;
> int is_dir, is_leaf;
> @@ -1780,6 +1780,7 @@ static void scan_extent_node(e2fsck_t ctx, struct problem_context *pctx,
> while (!pctx->errcode && info.num_entries-- > 0) {
> is_leaf = extent.e_flags & EXT2_EXTENT_FLAGS_LEAF;
> is_dir = LINUX_S_ISDIR(pctx->inode->i_mode);
> + last_lblk = extent.e_lblk + extent.e_len - 1;
>
> problem = 0;
> if (extent.e_pblk == 0 ||
> @@ -1788,6 +1789,8 @@ static void scan_extent_node(e2fsck_t ctx, struct problem_context *pctx,
> problem = PR_1_EXTENT_BAD_START_BLK;
> else if (extent.e_lblk < start_block)
> problem = PR_1_OUT_OF_ORDER_EXTENTS;
> + else if (end_block && last_lblk > end_block)
> + problem = PR_1_EXTENT_END_OUT_OF_BOUNDS;
> else if (is_leaf && extent.e_len == 0)
> problem = PR_1_EXTENT_LENGTH_ZERO;
> else if (is_leaf &&
> @@ -1822,10 +1825,9 @@ report_problem:
> }
>
> if (!is_leaf) {
> - blk64_t lblk;
> + blk64_t lblk = extent.e_lblk;
>
> blk = extent.e_pblk;
> - lblk = extent.e_lblk;
> pctx->errcode = ext2fs_extent_get(ehandle,
> EXT2_EXTENT_DOWN, &extent);
> if (pctx->errcode) {
> @@ -1847,7 +1849,8 @@ report_problem:
> if (fix_problem(ctx, problem, pctx))
> ext2fs_extent_fix_parents(ehandle);
> }
> - scan_extent_node(ctx, pctx, pb, extent.e_lblk, ehandle);
> + scan_extent_node(ctx, pctx, pb, extent.e_lblk,
> + last_lblk, ehandle);
> if (pctx->errcode)
> return;
> pctx->errcode = ext2fs_extent_get(ehandle,
> @@ -1928,10 +1931,10 @@ report_problem:
> if (is_dir && extent.e_len > 0)
> pb->last_db_block = blockcnt - 1;
> pb->previous_block = extent.e_pblk + extent.e_len - 1;
> - start_block = pb->last_block = extent.e_lblk + extent.e_len - 1;
> + start_block = pb->last_block = last_lblk;
> if (is_leaf && !is_dir &&
> !(extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT))
> - pb->last_init_lblock = extent.e_lblk + extent.e_len - 1;
> + pb->last_init_lblock = last_lblk;
> next:
> pctx->errcode = ext2fs_extent_get(ehandle,
> EXT2_EXTENT_NEXT_SIB,
> @@ -1967,7 +1970,7 @@ static void check_blocks_extents(e2fsck_t ctx, struct problem_context *pctx,
> ctx->extent_depth_count[info.max_depth]++;
> }
>
> - scan_extent_node(ctx, pctx, pb, 0, ehandle);
> + scan_extent_node(ctx, pctx, pb, 0, 0, ehandle);
> if (pctx->errcode &&
> fix_problem(ctx, PR_1_EXTENT_ITERATE_FAILURE, pctx)) {
> pb->num_blocks = 0;
> diff --git a/e2fsck/problem.c b/e2fsck/problem.c
> index 05ef626..6d03765 100644
> --- a/e2fsck/problem.c
> +++ b/e2fsck/problem.c
> @@ -954,6 +954,12 @@ static struct e2fsck_problem problem_table[] = {
> "Logical start %b does not match logical start %c at next level. "),
> PROMPT_FIX, 0 },
>
> + /* Extent end is out of bounds for the tree */
> + { PR_1_EXTENT_END_OUT_OF_BOUNDS,
> + N_("@i %i, end of extent exceeds allowed value\n\t(logical @b %c, physical @b %b, len %N)\n"),
> + PROMPT_CLEAR, 0 },
> +
> +
> /* Pass 1b errors */
>
> /* Pass 1B: Rescan for duplicate/bad blocks */
> diff --git a/e2fsck/problem.h b/e2fsck/problem.h
> index aed524d..b578678 100644
> --- a/e2fsck/problem.h
> +++ b/e2fsck/problem.h
> @@ -561,6 +561,7 @@ struct problem_context {
> /* Index start doesn't match start of next extent down */
> #define PR_1_EXTENT_INDEX_START_INVALID 0x01006D
>
> +#define PR_1_EXTENT_END_OUT_OF_BOUNDS 0x01006E
> /*
> * Pass 1b errors
> */
> --
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