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 60a07fb26475aeba5a197da6d32964e26370b723..95fdbe3e6ccafb0c3308dd98946c9b0807b75b16 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1570,8 +1570,11 @@ write:
                        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 dac50d8b2bb86a66d10daecddaa2b5a194c37964..3cf7494408ff2d4862e67f3017a414e66af43f8d 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2284,9 +2284,10 @@ static inline void clear_file(struct inode *inode, int type)
 
 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);
@@ -2297,7 +2298,12 @@ static inline bool f2fs_skip_inode_update(struct inode *inode, int dsync)
                        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 cfee75bf88d9ca3997db4b7811d6ad6392d26f49..9b93aea5cbeb37ea0f4db5ec99d4d92d4c22ea88 100644 (file)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -777,6 +777,10 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
                        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;
        }