4.18-stable review patch. If anyone has any objections, please let me know.
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From: Chao Yu yuchao0@huawei.com
[ Upstream commit a33c150237a20d97a174243bc658c86502f9d370 ]
Thread A Background GC - f2fs_setattr isize to 0 - truncate_setsize - gc_data_segment - f2fs_get_read_data_page page #0 - set_page_dirty - set_cold_data - f2fs_truncate
- f2fs_setattr isize to 4k - read 4k <--- hit data in cached page #0
Above race condition can cause read out invalid data in a truncated page, fix it by i_gc_rwsem[WRITE] lock.
Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/f2fs/data.c | 4 ++++ fs/f2fs/file.c | 37 +++++++++++++++++++++++-------------- 2 files changed, 27 insertions(+), 14 deletions(-)
--- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2149,8 +2149,12 @@ static void f2fs_write_failed(struct add
if (to > i_size) { down_write(&F2FS_I(inode)->i_mmap_sem); + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + truncate_pagecache(inode, i_size); f2fs_truncate_blocks(inode, i_size, true); + + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); up_write(&F2FS_I(inode)->i_mmap_sem); } } --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -782,22 +782,26 @@ int f2fs_setattr(struct dentry *dentry, }
if (attr->ia_valid & ATTR_SIZE) { - if (attr->ia_size <= i_size_read(inode)) { - down_write(&F2FS_I(inode)->i_mmap_sem); - truncate_setsize(inode, attr->ia_size); + bool to_smaller = (attr->ia_size <= i_size_read(inode)); + + down_write(&F2FS_I(inode)->i_mmap_sem); + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + + truncate_setsize(inode, attr->ia_size); + + if (to_smaller) err = f2fs_truncate(inode); - up_write(&F2FS_I(inode)->i_mmap_sem); - if (err) - return err; - } else { - /* - * do not trim all blocks after i_size if target size is - * larger than i_size. - */ - down_write(&F2FS_I(inode)->i_mmap_sem); - truncate_setsize(inode, attr->ia_size); - up_write(&F2FS_I(inode)->i_mmap_sem); + /* + * do not trim all blocks after i_size if target size is + * larger than i_size. + */ + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + up_write(&F2FS_I(inode)->i_mmap_sem); + + if (err) + return err;
+ if (!to_smaller) { /* should convert inline inode here */ if (!f2fs_may_inline_data(inode)) { err = f2fs_convert_inline_inode(inode); @@ -944,13 +948,18 @@ static int punch_hole(struct inode *inod
blk_start = (loff_t)pg_start << PAGE_SHIFT; blk_end = (loff_t)pg_end << PAGE_SHIFT; + down_write(&F2FS_I(inode)->i_mmap_sem); + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + truncate_inode_pages_range(mapping, blk_start, blk_end - 1);
f2fs_lock_op(sbi); ret = f2fs_truncate_hole(inode, pg_start, pg_end); f2fs_unlock_op(sbi); + + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); up_write(&F2FS_I(inode)->i_mmap_sem); } }