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| author | Ross Zwisler <ross.zwisler@linux.intel.com> | 2017-10-12 18:54:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-30 11:40:48 +0300 |
| commit | 22e5190899e8d159fe59e0c0e3b9a1085ee5d4e8 (patch) | |
| tree | 0e174ce26069b757d2640ba7e76fc602c0670279 /fs | |
| parent | 713cb65003f1d1038d211606871b12ff555fb3f3 (diff) | |
| download | linux-22e5190899e8d159fe59e0c0e3b9a1085ee5d4e8.tar.xz | |
ext4: prevent data corruption with journaling + DAX
commit e9072d859df3e0f2c3ba450f0d1739595c2d5d13 upstream.
The current code has the potential for data corruption when changing an
inode's journaling mode, as that can result in a subsequent unsafe change
in S_DAX.
I've captured an instance of this data corruption in the following fstest:
https://patchwork.kernel.org/patch/9948377/
Prevent this data corruption from happening by disallowing changes to the
journaling mode if the '-o dax' mount option was used. This means that for
a given filesystem we could have a mix of inodes using either DAX or
data journaling, but whatever state the inodes are in will be held for the
duration of the mount.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/inode.c | 5 | ||||
| -rw-r--r-- | fs/ext4/ioctl.c | 16 |
2 files changed, 13 insertions, 8 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 90afeb7293a6..38eb621edd80 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5967,11 +5967,6 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val) ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA); } ext4_set_aops(inode); - /* - * Update inode->i_flags after EXT4_INODE_JOURNAL_DATA was updated. - * E.g. S_DAX may get cleared / set. - */ - ext4_set_inode_flags(inode); jbd2_journal_unlock_updates(journal); percpu_up_write(&sbi->s_journal_flag_rwsem); diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 75d83471f65c..d97f40396765 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -291,10 +291,20 @@ flags_err: if (err) goto flags_out; - if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) + if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) { + /* + * Changes to the journaling mode can cause unsafe changes to + * S_DAX if we are using the DAX mount option. + */ + if (test_opt(inode->i_sb, DAX)) { + err = -EBUSY; + goto flags_out; + } + err = ext4_change_inode_journal_flag(inode, jflag); - if (err) - goto flags_out; + if (err) + goto flags_out; + } if (migrate) { if (flags & EXT4_EXTENTS_FL) err = ext4_ext_migrate(inode); |