On Wed, Nov 01, 2017 at 04:36:47PM +0100, Jan Kara wrote:
> From: Christoph Hellwig <hch@xxxxxx>
>
> Return IOMAP_F_DIRTY from xfs_file_iomap_begin() when asked to prepare
> blocks for writing and the inode is pinned, and has dirty fields other
> than the timestamps. In __xfs_filemap_fault() we then detect this case
> and call dax_finish_sync_fault() to make sure all metadata is committed,
> and to insert the page table entry.
>
> Note that this will also dirty corresponding radix tree entry which is
> what we want - fsync(2) will still provide data integrity guarantees for
> applications not using userspace flushing. And applications using
> userspace flushing can avoid calling fsync(2) and thus avoid the
> performance overhead.
>
> [JK: Added VM_SYNC flag handling]
>
> Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/xfs_file.c | 15 ++++++++++++++-
> fs/xfs/xfs_iomap.c | 5 +++++
> 2 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 4496b45678de..4827e82d5d2c 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -44,6 +44,7 @@
> #include <linux/falloc.h>
> #include <linux/pagevec.h>
> #include <linux/backing-dev.h>
> +#include <linux/mman.h>
>
> static const struct vm_operations_struct xfs_file_vm_ops;
>
> @@ -1040,7 +1041,11 @@ __xfs_filemap_fault(
>
> xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
> if (IS_DAX(inode)) {
> - ret = dax_iomap_fault(vmf, pe_size, NULL, &xfs_iomap_ops);
> + pfn_t pfn;
> +
> + ret = dax_iomap_fault(vmf, pe_size, &pfn, &xfs_iomap_ops);
> + if (ret & VM_FAULT_NEEDDSYNC)
> + ret = dax_finish_sync_fault(vmf, pe_size, pfn);
> } else {
> if (write_fault)
> ret = iomap_page_mkwrite(vmf, &xfs_iomap_ops);
> @@ -1110,6 +1115,13 @@ xfs_file_mmap(
> struct file *filp,
> struct vm_area_struct *vma)
> {
> + /*
> + * We don't support synchronous mappings for non-DAX files. At least
> + * until someone comes with a sensible use case.
> + */
> + if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC))
> + return -EOPNOTSUPP;
> +
> file_accessed(filp);
> vma->vm_ops = &xfs_file_vm_ops;
> if (IS_DAX(file_inode(filp)))
> @@ -1128,6 +1140,7 @@ 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,
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index f179bdf1644d..b43be199fbdf 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -33,6 +33,7 @@
> #include "xfs_error.h"
> #include "xfs_trans.h"
> #include "xfs_trans_space.h"
> +#include "xfs_inode_item.h"
> #include "xfs_iomap.h"
> #include "xfs_trace.h"
> #include "xfs_icache.h"
> @@ -1086,6 +1087,10 @@ xfs_file_iomap_begin(
> trace_xfs_iomap_found(ip, offset, length, 0, &imap);
> }
>
> + if ((flags & IOMAP_WRITE) && xfs_ipincount(ip) &&
> + (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
> + iomap->flags |= IOMAP_F_DIRTY;
> +
> xfs_bmbt_to_iomap(ip, iomap, &imap);
>
> if (shared)
> --
> 2.12.3
>
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