Factor outstanding I/O error handling

Cleanup: setting an outstanding error on a mapping was open coded too many
times.  Factor it out in mapping_set_error().
Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/gfs2/glops.c

@@ -163,10 +163,7 @@ static void inode_go_sync(struct gfs2_glock *gl)
 		if (ip) {
 			struct address_space *mapping = ip->i_inode.i_mapping;
 			int error = filemap_fdatawait(mapping);
-			if (error == -ENOSPC)
-				set_bit(AS_ENOSPC, &mapping->flags);
-			else if (error)
-				set_bit(AS_EIO, &mapping->flags);
+			mapping_set_error(mapping, error);
 		}
 		clear_bit(GLF_DIRTY, &gl->gl_flags);
 		gfs2_ail_empty_gl(gl);

fs/mpage.c

@@ -663,12 +663,7 @@ __mpage_writepage(struct bio *bio, struct page *page, get_block_t get_block,
 	/*
 	 * The caller has a ref on the inode, so *mapping is stable
 	 */
-	if (*ret) {
-		if (*ret == -ENOSPC)
-			set_bit(AS_ENOSPC, &mapping->flags);
-		else
-			set_bit(AS_EIO, &mapping->flags);
-	}
+	mapping_set_error(mapping, *ret);
 out:
 	return bio;
 }
@@ -776,14 +771,7 @@ mpage_writepages(struct address_space *mapping,
 
 			if (writepage) {
 				ret = (*writepage)(page, wbc);
-				if (ret) {
-					if (ret == -ENOSPC)
-						set_bit(AS_ENOSPC,
-							&mapping->flags);
-					else
-						set_bit(AS_EIO,
-							&mapping->flags);
-				}
+				mapping_set_error(mapping, ret);
 			} else {
 				bio = __mpage_writepage(bio, page, get_block,
 						&last_block_in_bio, &ret, wbc,

include/linux/pagemap.h

@@ -11,6 +11,7 @@
 #include <linux/compiler.h>
 #include <asm/uaccess.h>
 #include <linux/gfp.h>
+#include <linux/bitops.h>
 
 /*
  * Bits in mapping->flags.  The lower __GFP_BITS_SHIFT bits are the page
@@ -19,6 +20,16 @@
 #define	AS_EIO		(__GFP_BITS_SHIFT + 0)	/* IO error on async write */
 #define AS_ENOSPC	(__GFP_BITS_SHIFT + 1)	/* ENOSPC on async write */
 
+static inline void mapping_set_error(struct address_space *mapping, int error)
+{
+	if (error) {
+		if (error == -ENOSPC)
+			set_bit(AS_ENOSPC, &mapping->flags);
+		else
+			set_bit(AS_EIO, &mapping->flags);
+	}
+}
+
 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
 {
 	return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;

mm/page-writeback.c

@@ -683,12 +683,7 @@ int generic_writepages(struct address_space *mapping,
 			}
 
 			ret = (*writepage)(page, wbc);
-			if (ret) {
-				if (ret == -ENOSPC)
-					set_bit(AS_ENOSPC, &mapping->flags);
-				else
-					set_bit(AS_EIO, &mapping->flags);
-			}
+			mapping_set_error(mapping, ret);
 
 			if (unlikely(ret == AOP_WRITEPAGE_ACTIVATE))
 				unlock_page(page);

mm/vmscan.c

@@ -284,12 +284,8 @@ static void handle_write_error(struct address_space *mapping,
 				struct page *page, int error)
 {
 	lock_page(page);
-	if (page_mapping(page) == mapping) {
-		if (error == -ENOSPC)
-			set_bit(AS_ENOSPC, &mapping->flags);
-		else
-			set_bit(AS_EIO, &mapping->flags);
-	}
+	if (page_mapping(page) == mapping)
+		mapping_set_error(mapping, error);
 	unlock_page(page);
 }