On Wed, Mar 27, 2024 at 05:45:09PM +0100, Christian Brauner wrote:
> There's a bunch of flags that are purely based on what the file
> operations support while also never being conditionally set or unset.
> IOW, they're not subject to change for individual file opens. Imho, such
> flags don't need to live in f_mode they might as well live in the fops
> structs itself. And the fops struct already has that lonely
> mmap_supported_flags member. We might as well turn that into a generic
> fops_flags member and move a few flags from FMODE_* space into FOP_*
> space. That gets us four FMODE_* bits back and the ability for new
> static flags that are about file ops to not have to live in FMODE_*
> space but in their own FOP_* space. It's not the most beautiful thing
> ever but it gets the job done. Yes, there'll be an additional pointer
> chase but hopefully that won't matter for these flags.
>
> If this is palatable I suspect there's a few more we can move into there
> and that we can also redirect new flag suggestions that follow this
> pattern into the fops_flags field instead of f_mode. As of yet untested.
>
> (Fwiw, FMODE_NOACCOUNT and FMODE_BACKING could live in fops_flags as
> well because they're also completely static but they aren't really
> about file operations so they're better suited for FMODE_* imho.)
>
> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
.....
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 632653e00906..d13e21eb9a3c 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1230,8 +1230,7 @@ xfs_file_open(
> {
> if (xfs_is_shutdown(XFS_M(inode->i_sb)))
> return -EIO;
> - file->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC |
> - FMODE_DIO_PARALLEL_WRITE | FMODE_CAN_ODIRECT;
> + file->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;
> return generic_file_open(inode, file);
> }
>
> @@ -1490,7 +1489,6 @@ const struct file_operations xfs_file_operations = {
> .compat_ioctl = xfs_file_compat_ioctl,
> #endif
> .mmap = xfs_file_mmap,
> - .mmap_supported_flags = MAP_SYNC,
> .open = xfs_file_open,
> .release = xfs_file_release,
> .fsync = xfs_file_fsync,
> @@ -1498,6 +1496,8 @@ const struct file_operations xfs_file_operations = {
> .fallocate = xfs_file_fallocate,
> .fadvise = xfs_file_fadvise,
> .remap_file_range = xfs_file_remap_range,
> + .fops_flags = FOP_MMAP_SYNC | FOP_BUF_RASYNC | FOP_BUF_WASYNC |
> + FOP_DIO_PARALLEL_WRITE,
> };
>
> const struct file_operations xfs_dir_file_operations = {
> @@ -1510,4 +1510,6 @@ const struct file_operations xfs_dir_file_operations = {
> .compat_ioctl = xfs_file_compat_ioctl,
> #endif
> .fsync = xfs_dir_fsync,
> + .fops_flags = FOP_MMAP_SYNC | FOP_BUF_RASYNC | FOP_BUF_WASYNC |
> + FOP_DIO_PARALLEL_WRITE,
> };
Why do we need to set any of these for directory operations now that
we have a clear choice? i.e. we can't mmap directories, and the rest
of these flags are for read() and write() operations which we also
can't do on directories...
....
> @@ -1024,7 +1024,7 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags)
>
> /* File path supports NOWAIT for non-direct_IO only for block devices. */
> if (!(kiocb->ki_flags & IOCB_DIRECT) &&
> - !(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) &&
> + !fops_buf_wasync(kiocb->ki_filp) &&
> (req->flags & REQ_F_ISREG))
> goto copy_iov;
You should probably also fix that comment - WASYNC is set when the
filesystem supports NOWAIT for buffered writes.
-Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
