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 bo.li@oracle.com
---
v3: fix my stupid finger error.
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 b2c3514..9bce6e9 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4720,8 +4720,7 @@ 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 00ddf22..6c867ec 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -140,8 +140,11 @@ 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);
}
--
1.7.7.6
--
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