Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / fs / ext4 / file.c

diff --git a/kernel/fs/ext4/file.c b/kernel/fs/ext4/file.c
index 113837e..0d24ebc 100644 (file)
--- a/kernel/fs/ext4/file.c
+++ b/kernel/fs/ext4/file.c
@@ -209,15 +209,18 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
        int result;
        handle_t *handle = NULL;
-       struct super_block *sb = file_inode(vma->vm_file)->i_sb;
+       struct inode *inode = file_inode(vma->vm_file);
+       struct super_block *sb = inode->i_sb;
        bool write = vmf->flags & FAULT_FLAG_WRITE;
 
        if (write) {
                sb_start_pagefault(sb);
                file_update_time(vma->vm_file);
+               down_read(&EXT4_I(inode)->i_mmap_sem);
                handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
                                                EXT4_DATA_TRANS_BLOCKS(sb));
-       }
+       } else
+               down_read(&EXT4_I(inode)->i_mmap_sem);
 
        if (IS_ERR(handle))
                result = VM_FAULT_SIGBUS;
@@ -228,8 +231,10 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
        if (write) {
                if (!IS_ERR(handle))
                        ext4_journal_stop(handle);
+               up_read(&EXT4_I(inode)->i_mmap_sem);
                sb_end_pagefault(sb);
-       }
+       } else
+               up_read(&EXT4_I(inode)->i_mmap_sem);
 
        return result;
 }
@@ -246,10 +251,12 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
        if (write) {
                sb_start_pagefault(sb);
                file_update_time(vma->vm_file);
+               down_read(&EXT4_I(inode)->i_mmap_sem);
                handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
                                ext4_chunk_trans_blocks(inode,
                                                        PMD_SIZE / PAGE_SIZE));
-       }
+       } else
+               down_read(&EXT4_I(inode)->i_mmap_sem);
 
        if (IS_ERR(handle))
                result = VM_FAULT_SIGBUS;
@@ -260,30 +267,71 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
        if (write) {
                if (!IS_ERR(handle))
                        ext4_journal_stop(handle);
+               up_read(&EXT4_I(inode)->i_mmap_sem);
                sb_end_pagefault(sb);
-       }
+       } else
+               up_read(&EXT4_I(inode)->i_mmap_sem);
 
        return result;
 }
 
 static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-       return dax_mkwrite(vma, vmf, ext4_get_block_dax,
-                               ext4_end_io_unwritten);
+       int err;
+       struct inode *inode = file_inode(vma->vm_file);
+
+       sb_start_pagefault(inode->i_sb);
+       file_update_time(vma->vm_file);
+       down_read(&EXT4_I(inode)->i_mmap_sem);
+       err = __dax_mkwrite(vma, vmf, ext4_get_block_dax,
+                           ext4_end_io_unwritten);
+       up_read(&EXT4_I(inode)->i_mmap_sem);
+       sb_end_pagefault(inode->i_sb);
+
+       return err;
+}
+
+/*
+ * Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_mkwrite()
+ * handler we check for races agaist truncate. Note that since we cycle through
+ * i_mmap_sem, we are sure that also any hole punching that began before we
+ * were called is finished by now and so if it included part of the file we
+ * are working on, our pte will get unmapped and the check for pte_same() in
+ * wp_pfn_shared() fails. Thus fault gets retried and things work out as
+ * desired.
+ */
+static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma,
+                               struct vm_fault *vmf)
+{
+       struct inode *inode = file_inode(vma->vm_file);
+       struct super_block *sb = inode->i_sb;
+       int ret = VM_FAULT_NOPAGE;
+       loff_t size;
+
+       sb_start_pagefault(sb);
+       file_update_time(vma->vm_file);
+       down_read(&EXT4_I(inode)->i_mmap_sem);
+       size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+       if (vmf->pgoff >= size)
+               ret = VM_FAULT_SIGBUS;
+       up_read(&EXT4_I(inode)->i_mmap_sem);
+       sb_end_pagefault(sb);
+
+       return ret;
 }
 
 static const struct vm_operations_struct ext4_dax_vm_ops = {
        .fault          = ext4_dax_fault,
        .pmd_fault      = ext4_dax_pmd_fault,
        .page_mkwrite   = ext4_dax_mkwrite,
-       .pfn_mkwrite    = dax_pfn_mkwrite,
+       .pfn_mkwrite    = ext4_dax_pfn_mkwrite,
 };
 #else
 #define ext4_dax_vm_ops        ext4_file_vm_ops
 #endif
 
 static const struct vm_operations_struct ext4_file_vm_ops = {
-       .fault          = filemap_fault,
+       .fault          = ext4_filemap_fault,
        .map_pages      = filemap_map_pages,
        .page_mkwrite   = ext4_page_mkwrite,
 };