From b9c6f8e8372b804f28674bab5fbb28345120ba28 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Sun, 28 Oct 2012 22:24:57 -0400 Subject: [PATCH] ext4: fix unjournaled inode bitmap modification commit 53d4bffedfa9b4c53a31228bcb7639561df339e3 changed ext4_new_inode() such that the inode bitmap was being modified outside a transaction, which could lead to corruption, and was discovered when journal_checksum found a bad checksum in the journal during log replay. Nix ran into this when using the journal_async_commit mount option, which enables journal checksumming. The ensuing journal replay failures due to the bad checksums led to filesystem corruption reported as the now infamous "Apparent serious progressive ext4 data corruption bug" [ Changed by tytso to only call ext4_journal_get_write_access() only when we're fairly certain that we're going to allocate the inode. ] I've tested this by mounting with journal_checksum and running fsstress then dropping power; I've also tested by hacking DM to create snapshots w/o first quiescing, which allows me to test journal replay repeatedly w/o actually power-cycling the box. Without the patch I hit a journal checksum error every time. With this fix it survives many iterations. Reported-by: Nix Signed-off-by: Eric Sandeen Signed-off-by: "Theodore Ts'o" Cc: stable@vger.kernel.org --- fs/ext4/ialloc.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 4facdd29a350f..3a100e7a62a83 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -725,6 +725,10 @@ repeat_in_this_group: "inode=%lu", ino + 1); continue; } + BUFFER_TRACE(inode_bitmap_bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, inode_bitmap_bh); + if (err) + goto fail; ext4_lock_group(sb, group); ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data); ext4_unlock_group(sb, group); @@ -738,6 +742,11 @@ repeat_in_this_group: goto out; got: + BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata"); + err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh); + if (err) + goto fail; + /* We may have to initialize the block bitmap if it isn't already */ if (ext4_has_group_desc_csum(sb) && gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { @@ -771,11 +780,6 @@ got: goto fail; } - BUFFER_TRACE(inode_bitmap_bh, "get_write_access"); - err = ext4_journal_get_write_access(handle, inode_bitmap_bh); - if (err) - goto fail; - BUFFER_TRACE(group_desc_bh, "get_write_access"); err = ext4_journal_get_write_access(handle, group_desc_bh); if (err) @@ -823,11 +827,6 @@ got: } ext4_unlock_group(sb, group); - BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata"); - err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh); - if (err) - goto fail; - BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata"); err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh); if (err) -- 2.39.5