From: Changwei Ge chge@linux.alibaba.com Subject: ocfs2: no need try to truncate file beyond i_size

Linux fallocate(2) with FALLOC_FL_PUNCH_HOLE mode set, its offset can exceed inode size. Ocfs2 now does't allow that offset beyond inode size. This restriction is not necessary and voilates fallocate(2) semantics.

If fallocate(2) offset is beyond inode size, just return success and do nothing further.

Otherwise, ocfs2 will crash the kernel.

kernel BUG at fs/ocfs2//alloc.c:7264! ocfs2_truncate_inline+0x20f/0x360 [ocfs2] ? ocfs2_read_blocks+0x2f3/0x5f0 [ocfs2] ocfs2_remove_inode_range+0x23c/0xcb0 [ocfs2] ? ocfs2_read_inode_block+0x10/0x20 [ocfs2] ? ocfs2_allocate_extend_trans+0x1a0/0x1a0 [ocfs2] __ocfs2_change_file_space+0x4a5/0x650 [ocfs2] ocfs2_fallocate+0x83/0xa0 [ocfs2] ? __audit_syscall_entry+0xb8/0x100 ? __sb_start_write+0x3b/0x70 vfs_fallocate+0x148/0x230 SyS_fallocate+0x48/0x80 do_syscall_64+0x79/0x170

Link: http://lkml.kernel.org/r/20200407082754.17565-1-chge@linux.alibaba.com Signed-off-by: Changwei Ge chge@linux.alibaba.com Reviewed-by: Joseph Qi joseph.qi@linux.alibaba.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: Changwei Ge gechangwei@live.cn Cc: Gang He ghe@suse.com Cc: Jun Piao piaojun@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/ocfs2/alloc.c | 4 ++++ 1 file changed, 4 insertions(+)

--- a/fs/ocfs2/alloc.c~ocfs2-no-need-try-to-truncate-file-beyond-i_size +++ a/fs/ocfs2/alloc.c @@ -7402,6 +7402,10 @@ int ocfs2_truncate_inline(struct inode * struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data; struct ocfs2_inline_data *idata = &di->id2.i_data;

+ /* No need to punch hole beyond i_size. */ + if (start >= i_size_read(inode)) + return 0; + if (end > i_size_read(inode)) end = i_size_read(inode);

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