From 2a9a609a0c4a3b0a6892fbe360b8c419839e6da7 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 19 Aug 2020 18:19:52 -0400 Subject: [PATCH] virtiofs: add DAX mmap support Add DAX mmap() support. Signed-off-by: Stefan Hajnoczi Signed-off-by: Miklos Szeredi --- fs/fuse/dax.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ fs/fuse/file.c | 5 +++++ 2 files changed, 64 insertions(+) diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c index a8d311b2db8e..b8ec7d64aa68 100644 --- a/fs/fuse/dax.c +++ b/fs/fuse/dax.c @@ -575,6 +575,65 @@ ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) return ret; } +static vm_fault_t __fuse_dax_fault(struct vm_fault *vmf, + enum page_entry_size pe_size, bool write) +{ + vm_fault_t ret; + struct inode *inode = file_inode(vmf->vma->vm_file); + struct super_block *sb = inode->i_sb; + pfn_t pfn; + + if (write) + sb_start_pagefault(sb); + + ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL, &fuse_iomap_ops); + + if (ret & VM_FAULT_NEEDDSYNC) + ret = dax_finish_sync_fault(vmf, pe_size, pfn); + + if (write) + sb_end_pagefault(sb); + + return ret; +} + +static vm_fault_t fuse_dax_fault(struct vm_fault *vmf) +{ + return __fuse_dax_fault(vmf, PE_SIZE_PTE, + vmf->flags & FAULT_FLAG_WRITE); +} + +static vm_fault_t fuse_dax_huge_fault(struct vm_fault *vmf, + enum page_entry_size pe_size) +{ + return __fuse_dax_fault(vmf, pe_size, vmf->flags & FAULT_FLAG_WRITE); +} + +static vm_fault_t fuse_dax_page_mkwrite(struct vm_fault *vmf) +{ + return __fuse_dax_fault(vmf, PE_SIZE_PTE, true); +} + +static vm_fault_t fuse_dax_pfn_mkwrite(struct vm_fault *vmf) +{ + return __fuse_dax_fault(vmf, PE_SIZE_PTE, true); +} + +static const struct vm_operations_struct fuse_dax_vm_ops = { + .fault = fuse_dax_fault, + .huge_fault = fuse_dax_huge_fault, + .page_mkwrite = fuse_dax_page_mkwrite, + .pfn_mkwrite = fuse_dax_pfn_mkwrite, +}; + +int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma) +{ + file_accessed(file); + vma->vm_ops = &fuse_dax_vm_ops; + vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; + return 0; +} + static void fuse_free_dax_mem_ranges(struct list_head *mem_list) { struct fuse_dax_mapping *range, *temp; diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 6c586bc97b64..2aac787464bc 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2325,6 +2325,10 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma) { struct fuse_file *ff = file->private_data; + /* DAX mmap is superior to direct_io mmap */ + if (FUSE_IS_DAX(file_inode(file))) + return fuse_dax_mmap(file, vma); + if (ff->open_flags & FOPEN_DIRECT_IO) { /* Can't provide the coherency needed for MAP_SHARED */ if (vma->vm_flags & VM_MAYSHARE) @@ -3413,6 +3417,7 @@ static const struct file_operations fuse_file_operations = { .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, + .get_unmapped_area = thp_get_unmapped_area, .flock = fuse_file_flock, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write,