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ext4: Fix data exposure after failed AIO DIO

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When AIO DIO fails e.g. due to IO error, we must not convert unwritten
extents as that will expose uninitialized data. Handle this case
by clearing unwritten flag from io_end in case of error and thus
preventing extent conversion.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Jan Kara 2016-02-29 08:36:38 +11:00 committed by Dave Chinner
parent c19b104a67
commit 74c66bcb7e
3 changed files with 29 additions and 32 deletions
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30
fs/ext4/ext4.h
View File

@ -1504,15 +1504,6 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
}
static inline void ext4_set_io_unwritten_flag(struct inode *inode,
struct ext4_io_end *io_end)
{
if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
io_end->flag |= EXT4_IO_END_UNWRITTEN;
atomic_inc(&EXT4_I(inode)->i_unwritten);
}
}
static inline ext4_io_end_t *ext4_inode_aio(struct inode *inode)
{
return inode->i_private;
@ -3293,6 +3284,27 @@ extern struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
extern int ext4_resize_begin(struct super_block *sb);
extern void ext4_resize_end(struct super_block *sb);
static inline void ext4_set_io_unwritten_flag(struct inode *inode,
struct ext4_io_end *io_end)
{
if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
io_end->flag |= EXT4_IO_END_UNWRITTEN;
atomic_inc(&EXT4_I(inode)->i_unwritten);
}
}
static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
{
struct inode *inode = io_end->inode;
if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
/* Wake up anyone waiting on unwritten extent conversion */
if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
wake_up_all(ext4_ioend_wq(inode));
}
}
#endif /* __KERNEL__ */
#define EFSBADCRC EBADMSG /* Bad CRC detected */

21
fs/ext4/inode.c
View File

@ -3166,9 +3166,6 @@ static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
{
ext4_io_end_t *io_end = iocb->private;
if (size <= 0)
return 0;
/* if not async direct IO just return */
if (!io_end)
return 0;
@ -3179,6 +3176,14 @@ static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
size);
iocb->private = NULL;
/*
* Error during AIO DIO. We cannot convert unwritten extents as the
* data was not written. Just clear the unwritten flag and drop io_end.
*/
if (size <= 0) {
ext4_clear_io_unwritten_flag(io_end);
size = 0;
}
io_end->offset = offset;
io_end->size = size;
ext4_put_io_end(io_end);
@ -3306,16 +3311,6 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
if (io_end) {
ext4_inode_aio_set(inode, NULL);
ext4_put_io_end(io_end);
/*
* When no IO was submitted ext4_end_io_dio() was not
* called so we have to put iocb's reference.
*/
if (ret <= 0 && ret != -EIOCBQUEUED && iocb->private) {
WARN_ON(iocb->private != io_end);
WARN_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
ext4_put_io_end(io_end);
iocb->private = NULL;
}
}
if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
EXT4_STATE_DIO_UNWRITTEN)) {

10
fs/ext4/page-io.c
View File

@ -139,16 +139,6 @@ static void ext4_release_io_end(ext4_io_end_t *io_end)
kmem_cache_free(io_end_cachep, io_end);
}
static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
{
struct inode *inode = io_end->inode;
io_end->flag &= ~EXT4_IO_END_UNWRITTEN;
/* Wake up anyone waiting on unwritten extent conversion */
if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten))
wake_up_all(ext4_ioend_wq(inode));
}
/*
* Check a range of space and convert unwritten extents to written. Note that
* we are protected from truncate touching same part of extent tree by the