From: Ross Zwisler Subject: [PATCH v9 11/16] dax: dax_iomap_fault() needs to call iomap_end() Date: Tue, 1 Nov 2016 13:54:13 -0600 Message-ID: <1478030058-1422-12-git-send-email-ross.zwisler@linux.intel.com> References: <1478030058-1422-1-git-send-email-ross.zwisler@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Theodore Ts'o , Matthew Wilcox , Dave Chinner , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, Christoph Hellwig , linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Andreas Dilger , Alexander Viro , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jan Kara , linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrew Morton To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: In-Reply-To: <1478030058-1422-1-git-send-email-ross.zwisler-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: linux-ext4.vger.kernel.org Currently iomap_end() doesn't do anything for DAX page faults for both ext2 and XFS. ext2_iomap_end() just checks for a write underrun, and xfs_file_iomap_end() checks to see if it needs to finish a delayed allocation. However, in the future iomap_end() calls might be needed to make sure we have balanced allocations, locks, etc. So, add calls to iomap_end() with appropriate error handling to dax_iomap_fault(). Signed-off-by: Ross Zwisler Suggested-by: Jan Kara Reviewed-by: Jan Kara --- fs/dax.c | 37 +++++++++++++++++++++++++++++-------- 1 file changed, 29 insertions(+), 8 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 7737954..6edd89b 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1165,6 +1165,7 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, struct iomap iomap = { 0 }; unsigned flags = 0; int error, major = 0; + int locked_status = 0; void *entry; /* @@ -1194,7 +1195,7 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, goto unlock_entry; if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { error = -EIO; /* fs corruption? */ - goto unlock_entry; + goto finish_iomap; } sector = dax_iomap_sector(&iomap, pos); @@ -1216,13 +1217,15 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } if (error) - goto unlock_entry; + goto finish_iomap; if (!radix_tree_exceptional_entry(entry)) { vmf->page = entry; - return VM_FAULT_LOCKED; + locked_status = VM_FAULT_LOCKED; + } else { + vmf->entry = entry; + locked_status = VM_FAULT_DAX_LOCKED; } - vmf->entry = entry; - return VM_FAULT_DAX_LOCKED; + goto finish_iomap; } switch (iomap.type) { @@ -1237,8 +1240,10 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, break; case IOMAP_UNWRITTEN: case IOMAP_HOLE: - if (!(vmf->flags & FAULT_FLAG_WRITE)) - return dax_load_hole(mapping, entry, vmf); + if (!(vmf->flags & FAULT_FLAG_WRITE)) { + locked_status = dax_load_hole(mapping, entry, vmf); + break; + } /*FALLTHRU*/ default: WARN_ON_ONCE(1); @@ -1246,14 +1251,30 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, break; } + finish_iomap: + if (ops->iomap_end) { + if (error) { + /* keep previous error */ + ops->iomap_end(inode, pos, PAGE_SIZE, 0, flags, + &iomap); + } else { + error = ops->iomap_end(inode, pos, PAGE_SIZE, + PAGE_SIZE, flags, &iomap); + } + } unlock_entry: - put_locked_mapping_entry(mapping, vmf->pgoff, entry); + if (!locked_status || error) + put_locked_mapping_entry(mapping, vmf->pgoff, entry); out: if (error == -ENOMEM) return VM_FAULT_OOM | major; /* -EBUSY is fine, somebody else faulted on the same PTE */ if (error < 0 && error != -EBUSY) return VM_FAULT_SIGBUS | major; + if (locked_status) { + WARN_ON_ONCE(error); /* -EBUSY from ops->iomap_end? */ + return locked_status; + } return VM_FAULT_NOPAGE | major; } EXPORT_SYMBOL_GPL(dax_iomap_fault); -- 2.7.4