diff options
| author | Eryu Guan <guaneryu@gmail.com> | 2018-03-22 11:41:25 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-24 09:36:30 +0200 |
| commit | 5058b70d2118ee0304a2f3124946c4089b06abde (patch) | |
| tree | 37f4286e2b33ddc6cc9eeeda36cf98ecd4fbd983 /fs/ext4/inode.c | |
| parent | bd499f55384969d53c825fa7c3a0ae21c972c945 (diff) | |
ext4: protect i_disksize update by i_data_sem in direct write path
commit 73fdad00b208b139cf43f3163fbc0f67e4c6047c upstream.
i_disksize update should be protected by i_data_sem, by either taking
the lock explicitly or by using ext4_update_i_disksize() helper. But the
i_disksize updates in ext4_direct_IO_write() are not protected at all,
which may be racing with i_disksize updates in writeback path in
delalloc buffer write path.
This is found by code inspection, and I didn't hit any i_disksize
corruption due to this bug. Thanks to Jan Kara for catching this bug and
suggesting the fix!
Reported-by: Jan Kara <jack@suse.cz>
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 0b9f3f284799..69f017e88e89 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3614,7 +3614,6 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; - struct ext4_inode_info *ei = EXT4_I(inode); ssize_t ret; loff_t offset = iocb->ki_pos; size_t count = iov_iter_count(iter); @@ -3638,7 +3637,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) goto out; } orphan = 1; - ei->i_disksize = inode->i_size; + ext4_update_i_disksize(inode, inode->i_size); ext4_journal_stop(handle); } @@ -3746,7 +3745,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) if (ret > 0) { loff_t end = offset + ret; if (end > inode->i_size) { - ei->i_disksize = end; + ext4_update_i_disksize(inode, end); i_size_write(inode, end); /* * We're going to return a positive `ret' |