[PATCH] hfs: don't dirty unchanged inode

If inode size hasn't changed, don't do anything further in truncate, which
also prevents a dirty inode, what might upset some readonly devices quite
badly.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 5 insertions, 2 deletions

diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index cbc8510ad222..5ea6b3d45eaa 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -482,7 +482,8 @@ void hfs_file_truncate(struct inode *inode)
                 page_cache_release(page);
                 mark_inode_dirty(inode);
                 return;
-        }
+        } else if (inode->i_size == HFS_I(inode)->phys_size)
+                return;
         size = inode->i_size + HFS_SB(sb)->alloc_blksz - 1;
         blk_cnt = size / HFS_SB(sb)->alloc_blksz;
         alloc_cnt = HFS_I(inode)->alloc_blocks;
diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index 376498cc64fd..e7235ca79a95 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -461,7 +461,9 @@ void hfsplus_file_truncate(struct inode *inode)
                 page_cache_release(page);
                 mark_inode_dirty(inode);
                 return;
-        }
+        } else if (inode->i_size == HFSPLUS_I(inode).phys_size)
+                return;
+
         blk_cnt = (inode->i_size + HFSPLUS_SB(sb).alloc_blksz - 1) >> HFSPLUS_SB(sb).alloc_blksz_shift;
         alloc_cnt = HFSPLUS_I(inode).alloc_blocks;
         if (blk_cnt == alloc_cnt)