[Devel] [PATCH] reiserfs: add missing D-cache flushing

[Alexey Dobriyan]

Looks like, reiserfs_prepare_file_region_for_write() doesn't contain several
flush_dcache_page() calls.
Found with help from Dmitriy Monakhov <dmonakhov at openvz.org>

Dmitriy adds:

> Absolutely agree. This function is analog of generic  __block_prepare_write()
>
> comment before this block may confuse us:
> ---reiserfs/file.c:1039
> /* Now if all the write area lies past the file end, no point in
>          maping blocks, since there is none, so we just zero out remaining
>          parts of first and last pages in write area (if needed) */
>       if ((pos & ~((loff_t) PAGE_CACHE_SIZE - 1)) > inode->i_size) {
> ---
> but we can create mapping before file size was reduced and grow again

Signed-off-by: Alexey Dobriyan <adobriyan at openvz.org>
---

 fs/reiserfs/file.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/reiserfs/file.c
+++ b/fs/reiserfs/file.c
@@ -1043,6 +1043,7 @@ static int reiserfs_prepare_file_region_
 		if (from != 0) {	/* First page needs to be partially zeroed */
 			char *kaddr = kmap_atomic(prepared_pages[0], KM_USER0);
 			memset(kaddr, 0, from);
+			flush_dcache_page(prepared_pages[0]);
 			kunmap_atomic(kaddr, KM_USER0);
 		}
 		if (to != PAGE_CACHE_SIZE) {	/* Last page needs to be partially zeroed */
@@ -1050,6 +1051,7 @@ static int reiserfs_prepare_file_region_
 			    kmap_atomic(prepared_pages[num_pages - 1],
 					KM_USER0);
 			memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
+			flush_dcache_page(prepared_pages[num_pages - 1]);
 			kunmap_atomic(kaddr, KM_USER0);
 		}
 
@@ -1183,6 +1185,7 @@ static int reiserfs_prepare_file_region_
 							KM_USER0);
 					memset(kaddr + block_start, 0,
 					       from - block_start);
+					flush_dcache_page(prepared_pages[0]);
 					kunmap_atomic(kaddr, KM_USER0);
 					set_buffer_uptodate(bh);
 				}
@@ -1220,6 +1223,7 @@ static int reiserfs_prepare_file_region_
 							[num_pages - 1],
 							KM_USER0);
 					memset(kaddr + to, 0, block_end - to);
+					flush_dcache_page(prepared_pages[num_pages - 1]);
 					kunmap_atomic(kaddr, KM_USER0);
 					set_buffer_uptodate(bh);
 				}