On Wed, Apr 17, 2019 at 11:37:06PM +0800, Anand Jain wrote:
> When inode attribute flags is set through FS_IOC_SETFLAGS ioctl, there is
> a bit of duplicate codes, the following things happens twice -
> start/end_transaction, inode_inc_iversion(), current_time update to
> inode->i_ctime, and btrfs_update_inode(). These are updated both at
> btrfs_ioctl_setflags() and btrfs_set_props() as well. (RFC: So inode
> version and the generation number should have increased by +2, but I
> don't see that in the test case below ran without this patch)
>
> This patch merges these two duplicate codes at btrfs_ioctl_setflags().
>
> $ cat a
> mkfs.btrfs -fq /dev/sdb || exit
> mount /dev/sdb /btrfs
> touch /btrfs/file1
> sync
> echo before:
> btrfs in dump-super /dev/sdb | grep ^generation
> btrfs in dump-tree /dev/sdb | grep -A4 "257 XATTR_ITEM"
> btrfs in dump-tree /dev/sdb | grep -A4 "257 INODE_ITEM 0) item"
> echo
> echo "chattr +Ac /btrfs/file1"
> chattr +Ac /btrfs/file1
> sync
> echo after:
> btrfs in dump-super /dev/sdb | grep ^generation
> btrfs in dump-tree /dev/sdb | grep -A4 "257 XATTR_ITEM"
> btrfs in dump-tree /dev/sdb | grep -A4 "257 INODE_ITEM 0) item"
>
> $ umount /btrfs; ./a
> before:
> generation 6
> item 4 key (257 INODE_ITEM 0) itemoff 15881 itemsize 160
> generation 6 transid 6 size 0 nbytes 0
> block group 0 mode 100644 links 1 uid 0 gid 0 rdev 0
> sequence 19 flags 0x0(none)
>
> chattr +Ac /btrfs/file1
> after:
> generation 7
> item 6 key (257 XATTR_ITEM 550297449) itemoff 15815 itemsize 51
> location key (0 UNKNOWN.0 0) type XATTR
> transid 7 data_len 4 name_len 17
> name: btrfs.compression
> data zlib
> item 4 key (257 INODE_ITEM 0) itemoff 15881 itemsize 160
> generation 6 transid 7 size 0 nbytes 0
> block group 0 mode 100644 links 1 uid 0 gid 0 rdev 0
> sequence 21 flags 0xa00(NOATIME|COMPRESS)
>
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
> ---
> fs/btrfs/ioctl.c | 38 ++++++++++++++++++--------------------
> fs/btrfs/props.c | 6 +++---
> fs/btrfs/props.h | 3 +++
> 3 files changed, 24 insertions(+), 23 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 63e6e2f5b659..82772523bb87 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -192,6 +192,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
> u64 old_flags;
> unsigned int old_i_flags;
> umode_t mode;
> + const char *comp = NULL;
>
> if (!inode_owner_or_capable(inode))
> return -EPERM;
> @@ -283,14 +284,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
> if (fsflags & FS_NOCOMP_FL) {
> binode->flags &= ~BTRFS_INODE_COMPRESS;
> binode->flags |= BTRFS_INODE_NOCOMPRESS;
> -
> - /* set no-compression no need to validate prop here */
> - ret = btrfs_set_prop_trans(inode, "btrfs.compression", NULL,
> - 0, 0);
> - if (ret && ret != -ENODATA)
> - goto out_drop;
> } else if (fsflags & FS_COMPR_FL) {
> - const char *comp;
>
> if (IS_SWAPFILE(inode)) {
> ret = -ETXTBSY;
> @@ -300,36 +294,40 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
> binode->flags |= BTRFS_INODE_COMPRESS;
> binode->flags &= ~BTRFS_INODE_NOCOMPRESS;
>
> - /* compress_type is already validated during mount options */
> comp = btrfs_compress_type2str(fs_info->compress_type);
> if (!comp || comp[0] == 0)
> comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
> -
> - ret = btrfs_set_prop_trans(inode, "btrfs.compression", comp,
> - strlen(comp), 0);
> - if (ret)
> - goto out_drop;
> -
> } else {
> - /* reset prop, no need of validate prop here */
> - ret = btrfs_set_prop_trans(inode, "btrfs.compression", NULL,
> - 0, 0);
> - if (ret && ret != -ENODATA)
> - goto out_drop;
> binode->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
> }
>
> - trans = btrfs_start_transaction(root, 1);
> + trans = btrfs_start_transaction(root, 3);
This should reflect if the properties are actually changed or not, so
there's not unnecessary reservation made.
> if (IS_ERR(trans)) {
> ret = PTR_ERR(trans);
> goto out_drop;
> }
>
> + if (comp) {
> + ret = btrfs_set_prop(trans, inode, "btrfs.compression", comp,
> + strlen(comp), 0);
> + if (ret)
> + goto out_abort;
Transaction abort should be done at the place where they happen and not
aggregated.
I see now that the validation is not necessary here.
> + set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
> + } else {
> + ret = btrfs_set_prop(trans, inode, "btrfs.compression", NULL,
> + 0, 0);
> + if (ret && ret != -ENODATA)
> + goto out_abort;
Same.
> + }
> +
> btrfs_sync_inode_flags_to_i_flags(inode);
> inode_inc_iversion(inode);
> inode->i_ctime = current_time(inode);
> ret = btrfs_update_inode(trans, root, inode);
>
> + out_abort:
> + if (ret)
> + btrfs_abort_transaction(trans, ret);
> btrfs_end_transaction(trans);
> out_drop:
> if (ret) {
> diff --git a/fs/btrfs/props.c b/fs/btrfs/props.c
> index e356dd2a0f73..aedf5a7d69c9 100644
> --- a/fs/btrfs/props.c
> +++ b/fs/btrfs/props.c
> @@ -72,9 +72,9 @@ int btrfs_validate_prop(const char *name, const char *value, size_t value_len)
> return handler->validate(value, value_len);
> }
>
> -static int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
> - const char *name, const char *value, size_t value_len,
> - int flags)
> +int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
> + const char *name, const char *value, size_t value_len,
> + int flags)
Exporting a fuction should be in another patch.
> {
> const struct prop_handler *handler;
> int ret;
> diff --git a/fs/btrfs/props.h b/fs/btrfs/props.h
> index 01d2c1899bc7..30b99348977d 100644
> --- a/fs/btrfs/props.h
> +++ b/fs/btrfs/props.h
> @@ -12,6 +12,9 @@ void __init btrfs_props_init(void);
>
> int btrfs_set_prop_trans(struct inode *inode, const char *name,
> const char *value, size_t value_len, int flags);
> +int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
> + const char *name, const char *value, size_t value_len,
> + int flags);
> int btrfs_validate_prop(const char *name, const char *value, size_t value_len);
>
> int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path);
> --
> 2.17.1
