From: Jan Kara jack@suse.cz
commit 0b3171b6d195637f84ddf8b59bae818ea20bc8ac upstream.
Since commit 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure") we don't properly bail out of RWF_NOWAIT direct IO write if underlying blocks are not allocated. Also ext4_dio_write_checks() does not honor RWF_NOWAIT when re-acquiring i_rwsem. Fix both issues.
Fixes: 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure") Cc: stable@kernel.org Reported-by: Filipe Manana fdmanana@gmail.com Signed-off-by: Jan Kara jack@suse.cz Reviewed-by: Ritesh Harjani riteshh@linux.ibm.com Link: https://lore.kernel.org/r/20200708153516.9507-1-jack@suse.cz Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/file.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -428,6 +428,10 @@ restart: */ if (*ilock_shared && (!IS_NOSEC(inode) || *extend || !ext4_overwrite_io(inode, offset, count))) { + if (iocb->ki_flags & IOCB_NOWAIT) { + ret = -EAGAIN; + goto out; + } inode_unlock_shared(inode); *ilock_shared = false; inode_lock(inode);