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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>
This commit is contained in:
Chao Yu 2017-10-09 17:55:19 +08:00 committed by Jaegeuk Kim
parent ebf7c522fd
commit a0d00fad35
3 changed files with 15 additions and 2 deletions
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3
fs/f2fs/data.c
View File

@ -1570,8 +1570,11 @@ static int __write_data_page(struct page *page, bool *submitted,
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)

10
fs/f2fs/f2fs.h
View File

@ -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)

4
fs/f2fs/file.c
View File

@ -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;
}