From caa51d26f85c248f1c4f43a870ad3ef84bf9eb8f Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 1 Nov 2017 16:36:42 +0100 Subject: dax, iomap: Add support for synchronous faults Add a flag to iomap interface informing the caller that inode needs fdstasync(2) for returned extent to become persistent and use it in DAX fault code so that we don't map such extents into page tables immediately. Instead we propagate the information that fdatasync(2) is necessary from dax_iomap_fault() with a new VM_FAULT_NEEDDSYNC flag. Filesystem fault handler is then responsible for calling fdatasync(2) and inserting pfn into page tables. Reviewed-by: Ross Zwisler Reviewed-by: Christoph Hellwig Signed-off-by: Jan Kara Signed-off-by: Dan Williams --- include/linux/iomap.h | 5 +++++ include/linux/mm.h | 6 +++++- 2 files changed, 10 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/iomap.h b/include/linux/iomap.h index f64dc6ce5161..73e3b7085dbe 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -22,6 +22,11 @@ struct vm_fault; * Flags for all iomap mappings: */ #define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */ +/* + * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access + * written data and requires fdatasync to commit them to persistent storage. + */ +#define IOMAP_F_DIRTY 0x02 /* * Flags that only need to be reported for IOMAP_REPORT requests: diff --git a/include/linux/mm.h b/include/linux/mm.h index 5411cb7442de..f57e55782d7d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1182,6 +1182,9 @@ static inline void clear_page_pfmemalloc(struct page *page) #define VM_FAULT_RETRY 0x0400 /* ->fault blocked, must retry */ #define VM_FAULT_FALLBACK 0x0800 /* huge page fault failed, fall back to small */ #define VM_FAULT_DONE_COW 0x1000 /* ->fault has fully handled COW */ +#define VM_FAULT_NEEDDSYNC 0x2000 /* ->fault did not modify page tables + * and needs fsync() to complete (for + * synchronous page faults in DAX) */ #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \ VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \ @@ -1199,7 +1202,8 @@ static inline void clear_page_pfmemalloc(struct page *page) { VM_FAULT_LOCKED, "LOCKED" }, \ { VM_FAULT_RETRY, "RETRY" }, \ { VM_FAULT_FALLBACK, "FALLBACK" }, \ - { VM_FAULT_DONE_COW, "DONE_COW" } + { VM_FAULT_DONE_COW, "DONE_COW" }, \ + { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } /* Encode hstate index for a hwpoisoned large page */ #define VM_FAULT_SET_HINDEX(x) ((x) << 12) -- cgit v1.2.1