diff options
| author | Ross Zwisler <ross.zwisler@linux.intel.com> | 2016-02-26 15:19:49 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-02-27 10:28:52 -0800 |
| commit | 73f34a5e2ceddfca27c999c170620e6354aaf6d7 (patch) | |
| tree | bbadfef9feecde6b2961f248166f7a526004faaa | |
| parent | 0a6cf9137ded4856b41910a4336677ee0ffa6736 (diff) | |
| download | kvm-73f34a5e2ceddfca27c999c170620e6354aaf6d7.tar.gz | |
ext4: online defrag not supported with DAX
Online defrag operations for ext4 are hard coded to use the page cache.
See ext4_ioctl() -> ext4_move_extents() -> move_extent_per_page()
When combined with DAX I/O, which circumvents the page cache, this can
result in data corruption. This was observed with xfstests ext4/307 and
ext4/308.
Fix this by only allowing online defrag for non-DAX files.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/ext4/ioctl.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index a99b010e2194e3..eae5917c534e51 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -583,6 +583,11 @@ group_extend_out: "Online defrag not supported with bigalloc"); err = -EOPNOTSUPP; goto mext_out; + } else if (IS_DAX(inode)) { + ext4_msg(sb, KERN_ERR, + "Online defrag not supported with DAX"); + err = -EOPNOTSUPP; + goto mext_out; } err = mnt_want_write_file(filp); |