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 09:34:12 +0200 |
| commit | c636feb8ffe56f1cc1fafce87a67b1020761d24d (patch) | |
| tree | cbfd2a2d04b84135ea030441c3199cac6b8a205b /fs | |
| parent | a06b798c309ed8c919522c639e89613a013c13c4 (diff) | |
| download | linux-stable-c636feb8ffe56f1cc1fafce87a67b1020761d24d.tar.gz linux-stable-c636feb8ffe56f1cc1fafce87a67b1020761d24d.tar.bz2 linux-stable-c636feb8ffe56f1cc1fafce87a67b1020761d24d.zip | |
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')
| -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 5cccec68a0a5..6eaa864c05a9 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3396,7 +3396,6 @@ 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); @@ -3420,7 +3419,7 @@ 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); } @@ -3548,7 +3547,7 @@ 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' |