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-rw-r--r--fs/ext2/file.c84
1 files changed, 80 insertions, 4 deletions
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index 1982c3f11aec..11a42c5a09ae 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -27,27 +27,103 @@
#include "acl.h"
#ifdef CONFIG_FS_DAX
+/*
+ * The lock ordering for ext2 DAX fault paths is:
+ *
+ * mmap_sem (MM)
+ * sb_start_pagefault (vfs, freeze)
+ * ext2_inode_info->dax_sem
+ * address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX)
+ * ext2_inode_info->truncate_mutex
+ *
+ * The default page_lock and i_size verification done by non-DAX fault paths
+ * is sufficient because ext2 doesn't support hole punching.
+ */
static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- return dax_fault(vma, vmf, ext2_get_block, NULL);
+ struct inode *inode = file_inode(vma->vm_file);
+ struct ext2_inode_info *ei = EXT2_I(inode);
+ int ret;
+
+ if (vmf->flags & FAULT_FLAG_WRITE) {
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+ }
+ down_read(&ei->dax_sem);
+
+ ret = __dax_fault(vma, vmf, ext2_get_block, NULL);
+
+ up_read(&ei->dax_sem);
+ if (vmf->flags & FAULT_FLAG_WRITE)
+ sb_end_pagefault(inode->i_sb);
+ return ret;
}
static int ext2_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd, unsigned int flags)
{
- return dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block, NULL);
+ struct inode *inode = file_inode(vma->vm_file);
+ struct ext2_inode_info *ei = EXT2_I(inode);
+ int ret;
+
+ if (flags & FAULT_FLAG_WRITE) {
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+ }
+ down_read(&ei->dax_sem);
+
+ ret = __dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block, NULL);
+
+ up_read(&ei->dax_sem);
+ if (flags & FAULT_FLAG_WRITE)
+ sb_end_pagefault(inode->i_sb);
+ return ret;
}
static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- return dax_mkwrite(vma, vmf, ext2_get_block, NULL);
+ struct inode *inode = file_inode(vma->vm_file);
+ struct ext2_inode_info *ei = EXT2_I(inode);
+ int ret;
+
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+ down_read(&ei->dax_sem);
+
+ ret = __dax_mkwrite(vma, vmf, ext2_get_block, NULL);
+
+ up_read(&ei->dax_sem);
+ sb_end_pagefault(inode->i_sb);
+ return ret;
+}
+
+static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma,
+ struct vm_fault *vmf)
+{
+ struct inode *inode = file_inode(vma->vm_file);
+ struct ext2_inode_info *ei = EXT2_I(inode);
+ int ret = VM_FAULT_NOPAGE;
+ loff_t size;
+
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+ down_read(&ei->dax_sem);
+
+ /* check that the faulting page hasn't raced with truncate */
+ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (vmf->pgoff >= size)
+ ret = VM_FAULT_SIGBUS;
+
+ up_read(&ei->dax_sem);
+ sb_end_pagefault(inode->i_sb);
+ return ret;
}
static const struct vm_operations_struct ext2_dax_vm_ops = {
.fault = ext2_dax_fault,
.pmd_fault = ext2_dax_pmd_fault,
.page_mkwrite = ext2_dax_mkwrite,
- .pfn_mkwrite = dax_pfn_mkwrite,
+ .pfn_mkwrite = ext2_dax_pfn_mkwrite,
};
static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)