| From 7b4cc9787fe35b3ee2dfb1c35e22eafc32e00c33 Mon Sep 17 00:00:00 2001 |
| From: Eric Biggers <ebiggers@google.com> |
| Date: Sun, 30 Apr 2017 00:10:50 -0400 |
| Subject: [PATCH] ext4: evict inline data when writing to memory map |
| |
| commit 7b4cc9787fe35b3ee2dfb1c35e22eafc32e00c33 upstream. |
| |
| Currently the case of writing via mmap to a file with inline data is not |
| handled. This is maybe a rare case since it requires a writable memory |
| map of a very small file, but it is trivial to trigger with on |
| inline_data filesystem, and it causes the |
| 'BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA));' in |
| ext4_writepages() to be hit: |
| |
| mkfs.ext4 -O inline_data /dev/vdb |
| mount /dev/vdb /mnt |
| xfs_io -f /mnt/file \ |
| -c 'pwrite 0 1' \ |
| -c 'mmap -w 0 1m' \ |
| -c 'mwrite 0 1' \ |
| -c 'fsync' |
| |
| kernel BUG at fs/ext4/inode.c:2723! |
| invalid opcode: 0000 [#1] SMP |
| CPU: 1 PID: 2532 Comm: xfs_io Not tainted 4.11.0-rc1-xfstests-00301-g071d9acf3d1f #633 |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 |
| task: ffff88003d3a8040 task.stack: ffffc90000300000 |
| RIP: 0010:ext4_writepages+0xc89/0xf8a |
| RSP: 0018:ffffc90000303ca0 EFLAGS: 00010283 |
| RAX: 0000028410000000 RBX: ffff8800383fa3b0 RCX: ffffffff812afcdc |
| RDX: 00000a9d00000246 RSI: ffffffff81e660e0 RDI: 0000000000000246 |
| RBP: ffffc90000303dc0 R08: 0000000000000002 R09: 869618e8f99b4fa5 |
| R10: 00000000852287a2 R11: 00000000a03b49f4 R12: ffff88003808e698 |
| R13: 0000000000000000 R14: 7fffffffffffffff R15: 7fffffffffffffff |
| FS: 00007fd3e53094c0(0000) GS:ffff88003e400000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 00007fd3e4c51000 CR3: 000000003d554000 CR4: 00000000003406e0 |
| Call Trace: |
| ? _raw_spin_unlock+0x27/0x2a |
| ? kvm_clock_read+0x1e/0x20 |
| do_writepages+0x23/0x2c |
| ? do_writepages+0x23/0x2c |
| __filemap_fdatawrite_range+0x80/0x87 |
| filemap_write_and_wait_range+0x67/0x8c |
| ext4_sync_file+0x20e/0x472 |
| vfs_fsync_range+0x8e/0x9f |
| ? syscall_trace_enter+0x25b/0x2d0 |
| vfs_fsync+0x1c/0x1e |
| do_fsync+0x31/0x4a |
| SyS_fsync+0x10/0x14 |
| do_syscall_64+0x69/0x131 |
| entry_SYSCALL64_slow_path+0x25/0x25 |
| |
| We could try to be smart and keep the inline data in this case, or at |
| least support delayed allocation when allocating the block, but these |
| solutions would be more complicated and don't seem worthwhile given how |
| rare this case seems to be. So just fix the bug by calling |
| ext4_convert_inline_data() when we're asked to make a page writable, so |
| that any inline data gets evicted, with the block allocated immediately. |
| |
| Reported-by: Nick Alcock <nick.alcock@oracle.com> |
| Cc: stable@vger.kernel.org |
| Reviewed-by: Andreas Dilger <adilger@dilger.ca> |
| Signed-off-by: Eric Biggers <ebiggers@google.com> |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| |
| diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c |
| index b9ffa9f4191f..88203ae5b154 100644 |
| --- a/fs/ext4/inode.c |
| +++ b/fs/ext4/inode.c |
| @@ -5874,6 +5874,11 @@ int ext4_page_mkwrite(struct vm_fault *vmf) |
| file_update_time(vma->vm_file); |
| |
| down_read(&EXT4_I(inode)->i_mmap_sem); |
| + |
| + ret = ext4_convert_inline_data(inode); |
| + if (ret) |
| + goto out_ret; |
| + |
| /* Delalloc case is easy... */ |
| if (test_opt(inode->i_sb, DELALLOC) && |
| !ext4_should_journal_data(inode) && |
| -- |
| 2.12.0 |
| |