f2fs: read isize while holding i_mutex in fiemap

make sure the isize we read doesn't change during the process.

Signed-off-by: Fan li <fanofcode.li@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 89a978c57da9..ac5bea0f5f09 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -784,7 +784,7 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 {
         struct buffer_head map_bh;
         sector_t start_blk, last_blk;
-        loff_t isize = i_size_read(inode);
+        loff_t isize;
         u64 logical = 0, phys = 0, size = 0;
         u32 flags = 0;
         int ret = 0;
@@ -800,6 +800,8 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
         }
 
         mutex_lock(&inode->i_mutex);
+
+        isize = i_size_read(inode);
         if (start >= isize)
                 goto out;