f2fs: fix to avoid race when accessing last_disk_size
last_disk_size could be wrong due to concurrently updating, so using
i_sem semaphore to make last_disk_size updating exclusive to fix this
issue.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f1c37d6..431b82d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1568,8 +1568,11 @@
err = do_write_data_page(&fio);
}
}
+
+ down_write(&F2FS_I(inode)->i_sem);
if (F2FS_I(inode)->last_disk_size < psize)
F2FS_I(inode)->last_disk_size = psize;
+ up_write(&F2FS_I(inode)->i_sem);
done:
if (err && err != -ENOENT)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 666e3ef..668a32c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2282,9 +2282,10 @@
static inline bool f2fs_skip_inode_update(struct inode *inode, int dsync)
{
+ bool ret;
+
if (dsync) {
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
- bool ret;
spin_lock(&sbi->inode_lock[DIRTY_META]);
ret = list_empty(&F2FS_I(inode)->gdirty_list);
@@ -2295,7 +2296,12 @@
file_keep_isize(inode) ||
i_size_read(inode) & PAGE_MASK)
return false;
- return F2FS_I(inode)->last_disk_size == i_size_read(inode);
+
+ down_read(&F2FS_I(inode)->i_sem);
+ ret = F2FS_I(inode)->last_disk_size == i_size_read(inode);
+ up_read(&F2FS_I(inode)->i_sem);
+
+ return ret;
}
static inline int f2fs_readonly(struct super_block *sb)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 3a14a72..e240d78 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -758,6 +758,10 @@
inode->i_mtime = inode->i_ctime = current_time(inode);
}
+ down_write(&F2FS_I(inode)->i_sem);
+ F2FS_I(inode)->last_disk_size = i_size_read(inode);
+ up_write(&F2FS_I(inode)->i_sem);
+
size_changed = true;
}