From: "Darrick J. Wong" Subject: Re: [PATCH 18/18] xfs: support for synchronous DAX faults Date: Mon, 13 Nov 2017 18:19:42 -0800 Message-ID: <20171114021942.GI25227@magnolia> References: <20171101153648.30166-1-jack@suse.cz> <20171101153648.30166-19-jack@suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dan Williams , Ross Zwisler , Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-api@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, Christoph Hellwig To: Jan Kara Return-path: Content-Disposition: inline In-Reply-To: <20171101153648.30166-19-jack@suse.cz> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org On Wed, Nov 01, 2017 at 04:36:47PM +0100, Jan Kara wrote: > From: Christoph Hellwig > > 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 > Signed-off-by: Christoph Hellwig > Signed-off-by: Jan Kara Looks ok, Reviewed-by: Darrick J. Wong > --- > 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 > #include > #include > +#include > > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org