From 213490b301773ea9c6fb89a86424a6901fcdd069 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Tue, 11 Sep 2012 08:33:50 -0600 Subject: [PATCH] Btrfs: fix a bug of per-file nocow Users report a bug, the reproducer is: $ mkfs.btrfs /dev/loop0 $ mount /dev/loop0 /mnt/btrfs/ $ mkdir /mnt/btrfs/dir $ chattr +C /mnt/btrfs/dir/ $ dd if=/dev/zero of=/mnt/btrfs/dir/foo bs=4K count=10; $ lsattr /mnt/btrfs/dir/foo ---------------C- /mnt/btrfs/dir/foo $ filefrag /mnt/btrfs/dir/foo /mnt/btrfs/dir/foo: 1 extent found ---> an extent $ dd if=/dev/zero of=/mnt/btrfs/dir/foo bs=4K count=1 seek=5 conv=notrunc,nocreat; sync $ filefrag /mnt/btrfs/dir/foo /mnt/btrfs/dir/foo: 3 extents found ---> with nocow, btrfs breaks the extent into three parts The new created file should not only inherit the NODATACOW flag, but also honor NODATASUM flag, because we must do COW on a file extent with checksum. Signed-off-by: Liu Bo Signed-off-by: Chris Mason --- fs/btrfs/inode.c | 3 +-- fs/btrfs/ioctl.c | 5 ++++- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e95b1f9..67ed24a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4818,8 +4818,7 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans, if (S_ISREG(mode)) { if (btrfs_test_opt(root, NODATASUM)) BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; - if (btrfs_test_opt(root, NODATACOW) || - (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW)) + if (btrfs_test_opt(root, NODATACOW)) BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW; } diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index d4608ab..7624212 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -141,8 +141,11 @@ void btrfs_inherit_iflags(struct inode *inode, struct inode *dir) BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS; } - if (flags & BTRFS_INODE_NODATACOW) + if (flags & BTRFS_INODE_NODATACOW) { BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW; + if (S_ISREG(inode->i_mode)) + BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM; + } btrfs_update_iflags(inode); } -- 2.7.4