projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| b77986f5 GKH |
1 | From 8d5a803c6a6ce4ec258e31f76059ea5153ba46ef Mon Sep 17 00:00:00 2001 |
| 2 | From: Theodore Ts'o <tytso@mit.edu> | |
| 3 | Date: Thu, 12 Jul 2018 19:08:05 -0400 | |
| 4 | Subject: ext4: check for allocation block validity with block group locked | |
| 5 | ||
| 6 | From: Theodore Ts'o <tytso@mit.edu> | |
| 7 | ||
| 8 | commit 8d5a803c6a6ce4ec258e31f76059ea5153ba46ef upstream. | |
| 9 | ||
| 10 | With commit 044e6e3d74a3: "ext4: don't update checksum of new | |
| 11 | initialized bitmaps" the buffer valid bit will get set without | |
| 12 | actually setting up the checksum for the allocation bitmap, since the | |
| 13 | checksum will get calculated once we actually allocate an inode or | |
| 14 | block. | |
| 15 | ||
| 16 | If we are doing this, then we need to (re-)check the verified bit | |
| 17 | after we take the block group lock. Otherwise, we could race with | |
| 18 | another process reading and verifying the bitmap, which would then | |
| 19 | complain about the checksum being invalid. | |
| 20 | ||
| 21 | https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1780137 | |
| 22 | ||
| 23 | Signed-off-by: Theodore Ts'o <tytso@mit.edu> | |
| 24 | Cc: stable@kernel.org | |
| 25 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 26 | ||
| 27 | --- | |
| 28 | fs/ext4/balloc.c | 3 +++ | |
| 29 | fs/ext4/ialloc.c | 3 +++ | |
| 30 | 2 files changed, 6 insertions(+) | |
| 31 | ||
| 32 | --- a/fs/ext4/balloc.c | |
| 33 | +++ b/fs/ext4/balloc.c | |
| 34 | @@ -379,6 +379,8 @@ static int ext4_validate_block_bitmap(st | |
| 35 | return -EFSCORRUPTED; | |
| 36 | ||
| 37 | ext4_lock_group(sb, block_group); | |
| 38 | + if (buffer_verified(bh)) | |
| 39 | + goto verified; | |
| 40 | if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, | |
| 41 | desc, bh))) { | |
| 42 | ext4_unlock_group(sb, block_group); | |
| 43 | @@ -401,6 +403,7 @@ static int ext4_validate_block_bitmap(st | |
| 44 | return -EFSCORRUPTED; | |
| 45 | } | |
| 46 | set_buffer_verified(bh); | |
| 47 | +verified: | |
| 48 | ext4_unlock_group(sb, block_group); | |
| 49 | return 0; | |
| 50 | } | |
| 51 | --- a/fs/ext4/ialloc.c | |
| 52 | +++ b/fs/ext4/ialloc.c | |
| 53 | @@ -91,6 +91,8 @@ static int ext4_validate_inode_bitmap(st | |
| 54 | return -EFSCORRUPTED; | |
| 55 | ||
| 56 | ext4_lock_group(sb, block_group); | |
| 57 | + if (buffer_verified(bh)) | |
| 58 | + goto verified; | |
| 59 | blk = ext4_inode_bitmap(sb, desc); | |
| 60 | if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh, | |
| 61 | EXT4_INODES_PER_GROUP(sb) / 8)) { | |
| 62 | @@ -108,6 +110,7 @@ static int ext4_validate_inode_bitmap(st | |
| 63 | return -EFSBADCRC; | |
| 64 | } | |
| 65 | set_buffer_verified(bh); | |
| 66 | +verified: | |
| 67 | ext4_unlock_group(sb, block_group); | |
| 68 | return 0; | |
| 69 | } |