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Message-ID: <51E56407.5040505@redhat.com> Date: Tue, 16 Jul 2013 10:17:27 -0500 From: Eric Sandeen <sandeen@...hat.com> To: Dmitry Monakhov <dmonakhov@...nvz.org> CC: "Theodore Ts'o" <tytso@....edu>, 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 7/16/13 9:24 AM, Dmitry Monakhov wrote: > 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 Yes,this is the case where extents past EOF aren't updating the parent node in the extent tree: e2fsck 1.43-WIP (20-Jun-2013) Pass 1: Checking inodes, blocks, and sizes Inode 12, end of extent exceeds allowed value (logical block 301, physical block 1464, len 211) Clear? no Inode 12, i_blocks is 4112, should be 2424. Fix? no Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information Block bitmap differences: -(1464--1674) Fix? no The file looks like this: debugfs: ex f1 Level Entries Logical Physical Length Flags 0/ 1 1/ 1 0 - 300 1675 301 ^^^ length 301 ^^ last logical block at 300 1/ 1 1/ 8 0 - 0 1163 - 1163 1 1/ 1 2/ 8 1 - 99 1164 - 1262 99 Uninit 1/ 1 3/ 8 100 - 100 1263 - 1263 1 1/ 1 4/ 8 101 - 199 1264 - 1362 99 Uninit 1/ 1 5/ 8 200 - 200 1363 - 1363 1 1/ 1 6/ 8 201 - 299 1364 - 1462 99 Uninit 1/ 1 7/ 8 300 - 300 1463 - 1463 1 1/ 1 8/ 8 301 - 511 1464 - 1674 211 Uninit ^^ extent past EOF extends beyond parent Ted thought that was OK, I guess, but that seems very strange to me. Why would we NOT update the length/range of the parent block? Where EOF/i_size happens to land should be orthogonal to how the extent tree is described, I would expect. I asked in: Subject: fallocated blocks past EOF & past parent node range OK? but there's been no discussion so far. I'd like to understand why it's felt that the tree above is not considered to be corrupt. Thanks, -Eric >> >> - 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 >> */ >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in >> the body of a message to majordomo@...r.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@...r.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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