{
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;
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;
}
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;
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,
};
num = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
(pgoff_t)num);
- if (nr_pages == 0) {
- if (whence == SEEK_DATA)
- break;
-
- BUG_ON(whence != SEEK_HOLE);
- /*
- * If this is the first time to go into the loop and
- * offset is not beyond the end offset, it will be a
- * hole at this offset
- */
- if (lastoff == startoff || lastoff < endoff)
- found = 1;
- break;
- }
-
- /*
- * If this is the first time to go into the loop and
- * offset is smaller than the first page offset, it will be a
- * hole at this offset.
- */
- if (lastoff == startoff && whence == SEEK_HOLE &&
- lastoff < page_offset(pvec.pages[0])) {
- found = 1;
+ if (nr_pages == 0)
break;
- }
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
struct buffer_head *bh, *head;
/*
- * If the current offset is not beyond the end of given
- * range, it will be a hole.
+ * If current offset is smaller than the page offset,
+ * there is a hole at this offset.
*/
- if (lastoff < endoff && whence == SEEK_HOLE &&
- page->index > end) {
+ if (whence == SEEK_HOLE && lastoff < endoff &&
+ lastoff < page_offset(pvec.pages[i])) {
found = 1;
*offset = lastoff;
goto out;
}
+ if (page->index > end)
+ goto out;
+
lock_page(page);
if (unlikely(page->mapping != inode->i_mapping)) {
unlock_page(page);
}
- /*
- * The no. of pages is less than our desired, that would be a
- * hole in there.
- */
- if (nr_pages < num && whence == SEEK_HOLE) {
- found = 1;
- *offset = lastoff;
+ /* The no. of pages is less than our desired, we are done. */
+ if (nr_pages < num)
break;
- }
index = pvec.pages[i - 1]->index + 1;
pagevec_release(&pvec);
} while (index <= end);
+ if (whence == SEEK_HOLE && lastoff < endoff) {
+ found = 1;
+ *offset = lastoff;
+ }
out:
pagevec_release(&pvec);
return found;
projects / firefly-linux-kernel-4.4.55.git / blobdiff