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1dabdb6f GKH |
1 | From f35f06c35560a86e841631f0243b83a984dc11a9 Mon Sep 17 00:00:00 2001 |
2 | From: Filipe Manana <fdmanana@suse.com> | |
3 | Date: Tue, 26 Mar 2019 10:49:56 +0000 | |
4 | Subject: Btrfs: do not allow trimming when a fs is mounted with the nologreplay option | |
5 | ||
6 | From: Filipe Manana <fdmanana@suse.com> | |
7 | ||
8 | commit f35f06c35560a86e841631f0243b83a984dc11a9 upstream. | |
9 | ||
10 | Whan a filesystem is mounted with the nologreplay mount option, which | |
11 | requires it to be mounted in RO mode as well, we can not allow discard on | |
12 | free space inside block groups, because log trees refer to extents that | |
13 | are not pinned in a block group's free space cache (pinning the extents is | |
14 | precisely the first phase of replaying a log tree). | |
15 | ||
16 | So do not allow the fitrim ioctl to do anything when the filesystem is | |
17 | mounted with the nologreplay option, because later it can be mounted RW | |
18 | without that option, which causes log replay to happen and result in | |
19 | either a failure to replay the log trees (leading to a mount failure), a | |
20 | crash or some silent corruption. | |
21 | ||
22 | Reported-by: Darrick J. Wong <darrick.wong@oracle.com> | |
23 | Fixes: 96da09192cda ("btrfs: Introduce new mount option to disable tree log replay") | |
24 | CC: stable@vger.kernel.org # 4.9+ | |
25 | Reviewed-by: Nikolay Borisov <nborisov@suse.com> | |
26 | Signed-off-by: Filipe Manana <fdmanana@suse.com> | |
27 | Reviewed-by: David Sterba <dsterba@suse.com> | |
28 | Signed-off-by: David Sterba <dsterba@suse.com> | |
29 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
30 | ||
31 | --- | |
32 | fs/btrfs/ioctl.c | 10 ++++++++++ | |
33 | 1 file changed, 10 insertions(+) | |
34 | ||
35 | --- a/fs/btrfs/ioctl.c | |
36 | +++ b/fs/btrfs/ioctl.c | |
37 | @@ -496,6 +496,16 @@ static noinline int btrfs_ioctl_fitrim(s | |
38 | if (!capable(CAP_SYS_ADMIN)) | |
39 | return -EPERM; | |
40 | ||
41 | + /* | |
42 | + * If the fs is mounted with nologreplay, which requires it to be | |
43 | + * mounted in RO mode as well, we can not allow discard on free space | |
44 | + * inside block groups, because log trees refer to extents that are not | |
45 | + * pinned in a block group's free space cache (pinning the extents is | |
46 | + * precisely the first phase of replaying a log tree). | |
47 | + */ | |
48 | + if (btrfs_test_opt(fs_info, NOLOGREPLAY)) | |
49 | + return -EROFS; | |
50 | + | |
51 | rcu_read_lock(); | |
52 | list_for_each_entry_rcu(device, &fs_info->fs_devices->devices, | |
53 | dev_list) { |