Hi Jan, Here's my proposed approach to solving the problem you've identified. Cheers, - Ted >From 6d0b48896247dc70b16482a8ff4123d570285a2a Mon Sep 17 00:00:00 2001 From: Theodore Ts'o <tytso@xxxxxxx> Date: Sun, 5 May 2019 16:43:33 -0400 Subject: [PATCH] e2fsck: check and fix tails of all bitmap blocks Currently, e2fsck effectively checks only tail of the last inode and block bitmap in the filesystem. Thus if some previous bitmap has unset bits it goes unnoticed. Mostly these tail bits in the bitmap are ignored; however, if blocks_per_group are smaller than 8*blocksize, the multi-block allocator in the kernel can get confused when the tail bits are unset and return bogus free extent. Add support to libext2fs to check these bitmap tails when loading bitmaps (as that's about the only place which has access to the bitmap tail bits) and make e2fsck use this functionality to detect buggy bitmap tails and fix them (by rewriting the bitmaps). Reported-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> --- e2fsck/pass5.c | 40 ++++++++++++++++--- lib/ext2fs/ext2fs.h | 2 + lib/ext2fs/rw_bitmaps.c | 26 +++++++++++- tests/f_bitmaps/expect.1 | 2 + tests/f_dup/expect.1 | 2 + tests/f_dup2/expect.1 | 2 + tests/f_dup3/expect.1 | 2 + tests/f_end-bitmap/expect.1 | 2 + tests/f_illbbitmap/expect.1 | 2 + tests/f_illibitmap/expect.1 | 2 + tests/f_illitable_flexbg/expect.1 | 2 + tests/f_lpf/expect.1 | 2 + tests/f_overfsblks/expect.1 | 2 + tests/f_super_bad_csum/expect.1 | 4 +- tests/j_corrupt_ext_jnl_sb_csum/expect | 2 + tests/j_ext_long_trans/expect | 2 + tests/j_long_trans/expect | 2 + tests/j_long_trans_mcsum_32bit/expect | 2 + tests/j_long_trans_mcsum_64bit/expect | 2 + tests/j_recover_csum2_32bit/expect.1 | 2 + tests/j_recover_csum2_64bit/expect.1 | 2 + tests/j_short_trans/expect | 2 + tests/j_short_trans_64bit/expect | 2 + tests/j_short_trans_mcsum_64bit/expect | 2 + tests/j_short_trans_old_csum/expect | 2 + tests/j_short_trans_open_recover/expect | 2 + tests/j_short_trans_recover/expect | 2 + .../j_short_trans_recover_mcsum_64bit/expect | 2 + tests/t_replay_and_set/expect | 2 + 29 files changed, 113 insertions(+), 9 deletions(-) diff --git a/e2fsck/pass5.c b/e2fsck/pass5.c index 7803e8b80..810090970 100644 --- a/e2fsck/pass5.c +++ b/e2fsck/pass5.c @@ -838,6 +838,7 @@ static void check_inode_end(e2fsck_t ctx) ext2_filsys fs = ctx->fs; ext2_ino_t end, save_inodes_count, i; struct problem_context pctx; + int asked = 0; clear_problem_context(&pctx); @@ -851,11 +852,12 @@ static void check_inode_end(e2fsck_t ctx) return; } if (save_inodes_count == end) - return; + goto check_intra_bg_tail; /* protect loop from wrap-around if end is maxed */ for (i = save_inodes_count + 1; i <= end && i > save_inodes_count; i++) { if (!ext2fs_test_inode_bitmap(fs->inode_map, i)) { + asked = 1; if (fix_problem(ctx, PR_5_INODE_BMAP_PADDING, &pctx)) { for (; i <= end; i++) ext2fs_mark_inode_bitmap(fs->inode_map, @@ -875,6 +877,20 @@ static void check_inode_end(e2fsck_t ctx) ctx->flags |= E2F_FLAG_ABORT; /* fatal */ return; } + /* + * If the number of inodes per block group != blocksize, we + * can also have a potential problem with the tail bits in + * each individual inode bitmap block. If there is a problem, + * it would have been noticed when the bitmap was loaded. And + * fixing this is easy; all we need to do force the bitmap to + * be written back to disk. + */ +check_intra_bg_tail: + if (!asked && fs->flags & EXT2_FLAG_IBITMAP_TAIL_PROBLEM) + if (fix_problem(ctx, PR_5_INODE_BMAP_PADDING, &pctx)) + ext2fs_mark_ib_dirty(fs); + else + ext2fs_unmark_valid(fs); } static void check_block_end(e2fsck_t ctx) @@ -882,6 +898,7 @@ static void check_block_end(e2fsck_t ctx) ext2_filsys fs = ctx->fs; blk64_t end, save_blocks_count, i; struct problem_context pctx; + int asked = 0; clear_problem_context(&pctx); @@ -896,12 +913,13 @@ static void check_block_end(e2fsck_t ctx) return; } if (save_blocks_count == end) - return; + goto check_intra_bg_tail; /* Protect loop from wrap-around if end is maxed */ for (i = save_blocks_count + 1; i <= end && i > save_blocks_count; i++) { if (!ext2fs_test_block_bitmap2(fs->block_map, EXT2FS_C2B(fs, i))) { + asked = 1; if (fix_problem(ctx, PR_5_BLOCK_BMAP_PADDING, &pctx)) { for (; i <= end; i++) ext2fs_mark_block_bitmap2(fs->block_map, @@ -921,7 +939,19 @@ static void check_block_end(e2fsck_t ctx) ctx->flags |= E2F_FLAG_ABORT; /* fatal */ return; } + /* + * If the number of blocks per block group != blocksize, we + * can also have a potential problem with the tail bits in + * each individual block bitmap block. If there is a problem, + * it would have been noticed when the bitmap was loaded. And + * fixing this is easy; all we need to do force the bitmap to + * be written back to disk. + */ +check_intra_bg_tail: + if (!asked && fs->flags & EXT2_FLAG_BBITMAP_TAIL_PROBLEM) { + if (fix_problem(ctx, PR_5_BLOCK_BMAP_PADDING, &pctx)) + ext2fs_mark_bb_dirty(fs); + else + ext2fs_unmark_valid(fs); + } } - - - diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h index 7d7c346df..59fd97426 100644 --- a/lib/ext2fs/ext2fs.h +++ b/lib/ext2fs/ext2fs.h @@ -204,6 +204,8 @@ typedef struct ext2_file *ext2_file_t; #define EXT2_FLAG_IGNORE_CSUM_ERRORS 0x200000 #define EXT2_FLAG_SHARE_DUP 0x400000 #define EXT2_FLAG_IGNORE_SB_ERRORS 0x800000 +#define EXT2_FLAG_BBITMAP_TAIL_PROBLEM 0x1000000 +#define EXT2_FLAG_IBITMAP_TAIL_PROBLEM 0x2000000 /* * Special flag in the ext2 inode i_flag field that means that this is diff --git a/lib/ext2fs/rw_bitmaps.c b/lib/ext2fs/rw_bitmaps.c index e86bacd53..27c684d62 100644 --- a/lib/ext2fs/rw_bitmaps.c +++ b/lib/ext2fs/rw_bitmaps.c @@ -195,6 +195,16 @@ static errcode_t mark_uninit_bg_group_blocks(ext2_filsys fs) return 0; } +static int bitmap_tail_verify(unsigned char *bitmap, int first, int last) +{ + int i; + + for (i = first; i <= last; i++) + if (bitmap[i] != 0xff) + return 0; + return 1; +} + static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) { dgrp_t i; @@ -203,6 +213,7 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) errcode_t retval; int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8; int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8; + int tail_flags = 0; int csum_flag; unsigned int cnt; blk64_t blk; @@ -315,6 +326,9 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) EXT2_ET_BLOCK_BITMAP_CSUM_INVALID; goto cleanup; } + if (!bitmap_tail_verify(block_bitmap, + block_nbytes, fs->blocksize - 1)) + tail_flags |= EXT2_FLAG_BBITMAP_TAIL_PROBLEM; } else memset(block_bitmap, 0, block_nbytes); cnt = block_nbytes << 3; @@ -347,6 +361,9 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) EXT2_ET_INODE_BITMAP_CSUM_INVALID; goto cleanup; } + if (!bitmap_tail_verify(inode_bitmap, + inode_nbytes, fs->blocksize - 1)) + tail_flags |= EXT2_FLAG_IBITMAP_TAIL_PROBLEM; } else memset(inode_bitmap, 0, inode_nbytes); cnt = inode_nbytes << 3; @@ -366,10 +383,15 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) } success_cleanup: - if (inode_bitmap) + if (inode_bitmap) { ext2fs_free_mem(&inode_bitmap); - if (block_bitmap) + fs->flags &= ~EXT2_FLAG_IBITMAP_TAIL_PROBLEM; + } + if (block_bitmap) { ext2fs_free_mem(&block_bitmap); + fs->flags &= ~EXT2_FLAG_BBITMAP_TAIL_PROBLEM; + } + fs->flags |= tail_flags; return 0; cleanup: diff --git a/tests/f_bitmaps/expect.1 b/tests/f_bitmaps/expect.1 index 715984d4d..2e91113db 100644 --- a/tests/f_bitmaps/expect.1 +++ b/tests/f_bitmaps/expect.1 @@ -11,6 +11,8 @@ Fix? yes Inode bitmap differences: +11 -15 Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/32 files (9.1% non-contiguous), 22/100 blocks diff --git a/tests/f_dup/expect.1 b/tests/f_dup/expect.1 index 075e62c13..635a0dfc8 100644 --- a/tests/f_dup/expect.1 +++ b/tests/f_dup/expect.1 @@ -30,6 +30,8 @@ Fix? yes Free blocks count wrong (62, counted=60). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + Padding at end of block bitmap is not set. Fix? yes diff --git a/tests/f_dup2/expect.1 b/tests/f_dup2/expect.1 index 69aa21b4b..04d7304b4 100644 --- a/tests/f_dup2/expect.1 +++ b/tests/f_dup2/expect.1 @@ -37,6 +37,8 @@ Fix? yes Free blocks count wrong (26, counted=22). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + Padding at end of block bitmap is not set. Fix? yes diff --git a/tests/f_dup3/expect.1 b/tests/f_dup3/expect.1 index eab75a8dc..5f79cb891 100644 --- a/tests/f_dup3/expect.1 +++ b/tests/f_dup3/expect.1 @@ -39,6 +39,8 @@ Fix? yes Free blocks count wrong (20, counted=19). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 16/16 files (25.0% non-contiguous), 81/100 blocks diff --git a/tests/f_end-bitmap/expect.1 b/tests/f_end-bitmap/expect.1 index 87e2fd647..85c7e67f4 100644 --- a/tests/f_end-bitmap/expect.1 +++ b/tests/f_end-bitmap/expect.1 @@ -8,6 +8,8 @@ Pass 5: Checking group summary information Free blocks count wrong for group #0 (44, counted=63). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + Padding at end of block bitmap is not set. Fix? yes diff --git a/tests/f_illbbitmap/expect.1 b/tests/f_illbbitmap/expect.1 index 8746d23a5..40996cd61 100644 --- a/tests/f_illbbitmap/expect.1 +++ b/tests/f_illbbitmap/expect.1 @@ -22,6 +22,8 @@ Fix? yes Inode bitmap differences: -(12--21) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/32 files (0.0% non-contiguous), 22/100 blocks diff --git a/tests/f_illibitmap/expect.1 b/tests/f_illibitmap/expect.1 index 5bae25d14..bf21df7a7 100644 --- a/tests/f_illibitmap/expect.1 +++ b/tests/f_illibitmap/expect.1 @@ -19,6 +19,8 @@ Pass 5: Checking group summary information Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/32 files (0.0% non-contiguous), 22/100 blocks diff --git a/tests/f_illitable_flexbg/expect.1 b/tests/f_illitable_flexbg/expect.1 index fa42a0f8b..4ac124639 100644 --- a/tests/f_illitable_flexbg/expect.1 +++ b/tests/f_illitable_flexbg/expect.1 @@ -18,6 +18,8 @@ Pass 5: Checking group summary information Inode bitmap differences: -(65--128) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 12/256 files (0.0% non-contiguous), 31163/32768 blocks diff --git a/tests/f_lpf/expect.1 b/tests/f_lpf/expect.1 index 4f2853c5b..6ef996bb6 100644 --- a/tests/f_lpf/expect.1 +++ b/tests/f_lpf/expect.1 @@ -42,6 +42,8 @@ Fix? yes Free inodes count wrong (1, counted=0). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 16/16 files (12.5% non-contiguous), 67/100 blocks diff --git a/tests/f_overfsblks/expect.1 b/tests/f_overfsblks/expect.1 index e5b93f0d5..bc8f2a879 100644 --- a/tests/f_overfsblks/expect.1 +++ b/tests/f_overfsblks/expect.1 @@ -13,6 +13,8 @@ Pass 5: Checking group summary information Inode bitmap differences: -(12--21) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/32 files (0.0% non-contiguous), 22/100 blocks diff --git a/tests/f_super_bad_csum/expect.1 b/tests/f_super_bad_csum/expect.1 index 25ced5c8a..12adee970 100644 --- a/tests/f_super_bad_csum/expect.1 +++ b/tests/f_super_bad_csum/expect.1 @@ -5,8 +5,8 @@ Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information -Inode bitmap differences: Group 1 inode bitmap does not match checksum. -FIXED. +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/1024 files (0.0% non-contiguous), 1557/16384 blocks diff --git a/tests/j_corrupt_ext_jnl_sb_csum/expect b/tests/j_corrupt_ext_jnl_sb_csum/expect index 70a4fe721..4212a0007 100644 --- a/tests/j_corrupt_ext_jnl_sb_csum/expect +++ b/tests/j_corrupt_ext_jnl_sb_csum/expect @@ -12,6 +12,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/128 files (0.0% non-contiguous), 66/2048 blocks diff --git a/tests/j_ext_long_trans/expect b/tests/j_ext_long_trans/expect index d379610e7..ea3c87fcb 100644 --- a/tests/j_ext_long_trans/expect +++ b/tests/j_ext_long_trans/expect @@ -98,6 +98,8 @@ Fix? yes Free inodes count wrong (16372, counted=16373). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/16384 files (0.0% non-contiguous), 6228/262144 blocks diff --git a/tests/j_long_trans/expect b/tests/j_long_trans/expect index 7a175414b..82b3caf17 100644 --- a/tests/j_long_trans/expect +++ b/tests/j_long_trans/expect @@ -96,6 +96,8 @@ Fix? yes Free inodes count wrong (16372, counted=16373). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + Recreate journal? yes Creating journal (8192 blocks): Done. diff --git a/tests/j_long_trans_mcsum_32bit/expect b/tests/j_long_trans_mcsum_32bit/expect index a808d9f4d..ffae07a69 100644 --- a/tests/j_long_trans_mcsum_32bit/expect +++ b/tests/j_long_trans_mcsum_32bit/expect @@ -135,6 +135,8 @@ Fix? yes Free inodes count wrong (32756, counted=32757). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + Recreate journal? yes Creating journal (16384 blocks): Done. diff --git a/tests/j_long_trans_mcsum_64bit/expect b/tests/j_long_trans_mcsum_64bit/expect index 76e109a42..e891def16 100644 --- a/tests/j_long_trans_mcsum_64bit/expect +++ b/tests/j_long_trans_mcsum_64bit/expect @@ -134,6 +134,8 @@ Fix? yes Free inodes count wrong (32756, counted=32757). Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + Recreate journal? yes Creating journal (16384 blocks): Done. diff --git a/tests/j_recover_csum2_32bit/expect.1 b/tests/j_recover_csum2_32bit/expect.1 index 491784a25..fdbda36e2 100644 --- a/tests/j_recover_csum2_32bit/expect.1 +++ b/tests/j_recover_csum2_32bit/expect.1 @@ -10,6 +10,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/8192 files (0.0% non-contiguous), 7739/131072 blocks diff --git a/tests/j_recover_csum2_64bit/expect.1 b/tests/j_recover_csum2_64bit/expect.1 index 491784a25..fdbda36e2 100644 --- a/tests/j_recover_csum2_64bit/expect.1 +++ b/tests/j_recover_csum2_64bit/expect.1 @@ -10,6 +10,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/8192 files (0.0% non-contiguous), 7739/131072 blocks diff --git a/tests/j_short_trans/expect b/tests/j_short_trans/expect index bcc8fe82a..2bd0e5069 100644 --- a/tests/j_short_trans/expect +++ b/tests/j_short_trans/expect @@ -32,6 +32,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/16384 files (0.0% non-contiguous), 5164/65536 blocks diff --git a/tests/j_short_trans_64bit/expect b/tests/j_short_trans_64bit/expect index f9971eba3..808dc61df 100644 --- a/tests/j_short_trans_64bit/expect +++ b/tests/j_short_trans_64bit/expect @@ -34,6 +34,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/16384 files (0.0% non-contiguous), 5196/65536 blocks diff --git a/tests/j_short_trans_mcsum_64bit/expect b/tests/j_short_trans_mcsum_64bit/expect index d876ff095..d73e28297 100644 --- a/tests/j_short_trans_mcsum_64bit/expect +++ b/tests/j_short_trans_mcsum_64bit/expect @@ -34,6 +34,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/32768 files (0.0% non-contiguous), 6353/131072 blocks diff --git a/tests/j_short_trans_old_csum/expect b/tests/j_short_trans_old_csum/expect index 29ac27fb3..6cf06d4a2 100644 --- a/tests/j_short_trans_old_csum/expect +++ b/tests/j_short_trans_old_csum/expect @@ -34,6 +34,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/16384 files (0.0% non-contiguous), 5164/65536 blocks diff --git a/tests/j_short_trans_open_recover/expect b/tests/j_short_trans_open_recover/expect index be6e363dc..3e868197d 100644 --- a/tests/j_short_trans_open_recover/expect +++ b/tests/j_short_trans_open_recover/expect @@ -37,6 +37,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/16384 files (0.0% non-contiguous), 5164/65536 blocks diff --git a/tests/j_short_trans_recover/expect b/tests/j_short_trans_recover/expect index 75867337f..508858c98 100644 --- a/tests/j_short_trans_recover/expect +++ b/tests/j_short_trans_recover/expect @@ -34,6 +34,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/16384 files (0.0% non-contiguous), 5164/65536 blocks diff --git a/tests/j_short_trans_recover_mcsum_64bit/expect b/tests/j_short_trans_recover_mcsum_64bit/expect index 9cc330978..8c637f122 100644 --- a/tests/j_short_trans_recover_mcsum_64bit/expect +++ b/tests/j_short_trans_recover_mcsum_64bit/expect @@ -36,6 +36,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/32768 files (0.0% non-contiguous), 6353/131072 blocks diff --git a/tests/t_replay_and_set/expect b/tests/t_replay_and_set/expect index f63a73af5..3e19d92e9 100644 --- a/tests/t_replay_and_set/expect +++ b/tests/t_replay_and_set/expect @@ -30,6 +30,8 @@ Fix? yes Inode bitmap differences: +(1--11) Fix? yes +Padding at end of inode bitmap is not set. Fix? yes + test_filesys: ***** FILE SYSTEM WAS MODIFIED ***** test_filesys: 11/16384 files (0.0% non-contiguous), 5164/65536 blocks -- 2.19.1