logfs: survive logfs_buf_recover read errors

Refusing to mount beats a kernel crash.

Signed-off-by: Joern Engel <joern@logfs.org>

3 files changed, 13 insertions, 11 deletions

diff --git a/fs/logfs/journal.c b/fs/logfs/journal.c
index fb0a613f885b..4b0e0616b357 100644
--- a/fs/logfs/journal.c
+++ b/fs/logfs/journal.c
@@ -132,10 +132,9 @@ static int read_area(struct super_block *sb, struct logfs_je_area *a)
 
         ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
         if (super->s_writesize > 1)
-                logfs_buf_recover(area, ofs, a + 1, super->s_writesize);
+                return logfs_buf_recover(area, ofs, a + 1, super->s_writesize);
         else
-                logfs_buf_recover(area, ofs, NULL, 0);
-        return 0;
+                return logfs_buf_recover(area, ofs, NULL, 0);
 }
 
 static void *unpack(void *from, void *to)
@@ -245,7 +244,7 @@ static int read_je(struct super_block *sb, u64 ofs)
                 read_erasecount(sb, unpack(jh, scratch));
                 break;
         case JE_AREA:
-                read_area(sb, unpack(jh, scratch));
+                err = read_area(sb, unpack(jh, scratch));
                 break;
         case JE_OBJ_ALIAS:
                 err = logfs_load_object_aliases(sb, unpack(jh, scratch),
diff --git a/fs/logfs/logfs.h b/fs/logfs/logfs.h
index 0a3df1a0c936..32bf55616e56 100644
--- a/fs/logfs/logfs.h
+++ b/fs/logfs/logfs.h
@@ -598,19 +598,19 @@ void freeseg(struct super_block *sb, u32 segno);
 int logfs_init_areas(struct super_block *sb);
 void logfs_cleanup_areas(struct super_block *sb);
 int logfs_open_area(struct logfs_area *area, size_t bytes);
-void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
+int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
                 int use_filler);
 
-static inline void logfs_buf_write(struct logfs_area *area, u64 ofs,
+static inline int logfs_buf_write(struct logfs_area *area, u64 ofs,
                 void *buf, size_t len)
 {
-        __logfs_buf_write(area, ofs, buf, len, 0);
+        return __logfs_buf_write(area, ofs, buf, len, 0);
 }
 
-static inline void logfs_buf_recover(struct logfs_area *area, u64 ofs,
+static inline int logfs_buf_recover(struct logfs_area *area, u64 ofs,
                 void *buf, size_t len)
 {
-        __logfs_buf_write(area, ofs, buf, len, 1);
+        return __logfs_buf_write(area, ofs, buf, len, 1);
 }
 
 /* super.c */
diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c
index f77ce2b470ba..a9657afb70ad 100644
--- a/fs/logfs/segment.c
+++ b/fs/logfs/segment.c
@@ -67,7 +67,7 @@ static struct page *get_mapping_page(struct super_block *sb, pgoff_t index,
         return page;
 }
 
-void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
+int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
                 int use_filler)
 {
         pgoff_t index = ofs >> PAGE_SHIFT;
@@ -81,8 +81,10 @@ void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
                 copylen = min((ulong)len, PAGE_SIZE - offset);
 
                 page = get_mapping_page(area->a_sb, index, use_filler);
-                SetPageUptodate(page);
+                if (IS_ERR(page))
+                        return PTR_ERR(page);
                 BUG_ON(!page); /* FIXME: reserve a pool */
+                SetPageUptodate(page);
                 memcpy(page_address(page) + offset, buf, copylen);
                 SetPagePrivate(page);
                 page_cache_release(page);
@@ -92,6 +94,7 @@ void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
                 offset = 0;
                 index++;
         } while (len);
+        return 0;
 }
 
 static void pad_partial_page(struct logfs_area *area)