f2fs_preallocate_blocks() identifies direct IOs using the IOCB_DIRECT flag for a kiocb structure. However, the file system direct IO handler function f2fs_direct_IO() may have decided that a direct IO has to be exececuted as a buffered IO using the function f2fs_force_buffered_io(). This is the case for instance for volumes including zoned block device and for unaligned write IOs with LFS mode enabled.
These 2 different methods of identifying direct IOs can result in inconsistencies generating stale data access for direct reads after a direct IO write that is treated as a buffered write. Fix this inconsistency by combining the IOCB_DIRECT flag test with the result of f2fs_force_buffered_io(). Reported-by: Javier Gonzalez <[email protected]> Signed-off-by: Damien Le Moal <[email protected]> --- fs/f2fs/data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 5755e897a5f0..8ac2d3b70022 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1073,6 +1073,8 @@ int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from) int flag; int err = 0; bool direct_io = iocb->ki_flags & IOCB_DIRECT; + bool do_direct_io = direct_io && + !f2fs_force_buffered_io(inode, iocb, from); /* convert inline data for Direct I/O*/ if (direct_io) { @@ -1081,7 +1083,7 @@ int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from) return err; } - if (direct_io && allow_outplace_dio(inode, iocb, from)) + if (do_direct_io && allow_outplace_dio(inode, iocb, from)) return 0; if (is_inode_flag_set(inode, FI_NO_PREALLOC)) -- 2.23.0 _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
