search for: iov_iter_fault_in_readable

...ped and the mmaped buffer is passed to pwrite to write to the same page of the same file. In btrfs_file_aio_write(), the pages is locked by prepare_pages(). So when btrfs_copy_from_user() is called, page fault happens and the same page needs to be locked again in filemap_fault(). The fix is to move iov_iter_fault_in_readable() before prepage_pages() to make page fault happen before pages are locked. And also disable page fault in critical region in btrfs_copy_from_user(). Signed-off-by: Xin Zhong <xin.zhong@intel.com> --- fs/btrfs/file.c | 23 +++++------------------ 1 files changed, 5 insertions(+), 18 delet...

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 All, I believe that I can pretty reliably reproduce the BUG mentioned in the attached dmesg output. (This doesn''t mean that you can, but I''ll detail what I''ve done here.) [This BUG is the same one that I reported last night.] 1) Create a 2 GB dynamically expanding disk. 2) Attach it to a VirtualBox machine. 3) Start the

V1->V2: Check to see if our current ppos is >= i_size after a short DIO read, just in case it was actually a short read and we need to just return. This is similar to what already happens in the write case. If we have a short read while doing O_DIRECT, instead of just returning, fallthrough and try to read the rest via buffered IO. BTRFS needs this because if we encounter a compressed or