Re: [PATCH 11/29] xfs: pass an initialized xfs_da_args to xfs_attr_get

Darrick J. Wong
2020-01-21T18:12:55Z

On Tue, Jan 14, 2020 at 09:10:33AM +0100, Christoph Hellwig wrote:
> Instead of converting from one style of arguments to another in
> xfs_attr_set, pass the structure from higher up in the call chain.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/libxfs/xfs_attr.c | 80 ++++++++++++----------------------------
> fs/xfs/libxfs/xfs_attr.h | 4 +-
> fs/xfs/xfs_acl.c | 35 ++++++++----------
> fs/xfs/xfs_ioctl.c | 25 ++++++++-----
> fs/xfs/xfs_xattr.c | 24 ++++++------
> 5 files changed, 68 insertions(+), 100 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index c565e510fccc..4aaec6304f98 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -56,26 +56,6 @@ STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
> STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
> STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
>
> -
> -STATIC int
> -xfs_attr_args_init(
> - struct xfs_da_args *args,
> - struct xfs_inode *dp,
> - const unsigned char *name,
> - size_t namelen,
> - int flags)
> -{
> - memset(args, 0, sizeof(*args));
> - args->geo = dp->i_mount->m_attr_geo;
> - args->whichfork = XFS_ATTR_FORK;
> - args->dp = dp;
> - args->flags = flags;
> - args->name = name;
> - args->namelen = namelen;
> - args->hashval = xfs_da_hashname(args->name, args->namelen);
> - return 0;
> -}
> -
> int
> xfs_inode_hasattr(
> struct xfs_inode *ip)
> @@ -115,15 +95,15 @@ xfs_attr_get_ilocked(
> /*
> * Retrieve an extended attribute by name, and its value if requested.
> *
> - * If ATTR_KERNOVAL is set in @flags, then the caller does not want the value,
> - * just an indication whether the attribute exists and the size of the value if
> - * it exists. The size is returned in @valuelenp,
> + * If ATTR_KERNOVAL is set in args->flags, then the caller does not want the

"...is set in @args->flags..." ?

(I mean... it's pretty obvious to a human that "args" refers to the
parameter, but I dunno if the automated scanning tools are going to get
all cranky if we don't @ it.)

With that fixed,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> + * value, just an indication whether the attribute exists and the size of the
> + * value if it exists. The size is returned in args.valuelen.
> *
> * If the attribute is found, but exceeds the size limit set by the caller in
> - * @valuelenp, return -ERANGE with the size of the attribute that was found in
> - * @valuelenp.
> + * args->valuelen, return -ERANGE with the size of the attribute that was found
> + * in args->valuelen.
> *
> - * If ATTR_ALLOC is set in @flags, allocate the buffer for the value after
> + * If ATTR_ALLOC is set in args->flags, allocate the buffer for the value after
> * existence of the attribute has been determined. On success, return that
> * buffer to the caller and leave them to free it. On failure, free any
> * allocated buffer and ensure the buffer pointer returned to the caller is
> @@ -131,51 +111,37 @@ xfs_attr_get_ilocked(
> */
> int
> xfs_attr_get(
> - struct xfs_inode *ip,
> - const unsigned char *name,
> - size_t namelen,
> - unsigned char **value,
> - int *valuelenp,
> - int flags)
> + struct xfs_da_args *args)
> {
> - struct xfs_da_args args;
> uint lock_mode;
> int error;
>
> - ASSERT((flags & (ATTR_ALLOC | ATTR_KERNOVAL)) || *value);
> + ASSERT((args->flags & (ATTR_ALLOC | ATTR_KERNOVAL)) || args->value);
>
> - XFS_STATS_INC(ip->i_mount, xs_attr_get);
> + XFS_STATS_INC(args->dp->i_mount, xs_attr_get);
>
> - if (XFS_FORCED_SHUTDOWN(ip->i_mount))
> + if (XFS_FORCED_SHUTDOWN(args->dp->i_mount))
> return -EIO;
>
> - error = xfs_attr_args_init(&args, ip, name, namelen, flags);
> - if (error)
> - return error;
> + args->geo = args->dp->i_mount->m_attr_geo;
> + args->whichfork = XFS_ATTR_FORK;
> + args->hashval = xfs_da_hashname(args->name, args->namelen);
>
> /* Entirely possible to look up a name which doesn't exist */
> - args.op_flags = XFS_DA_OP_OKNOENT;
> - if (flags & ATTR_ALLOC)
> - args.op_flags |= XFS_DA_OP_ALLOCVAL;
> - else
> - args.value = *value;
> - args.valuelen = *valuelenp;
> + args->op_flags = XFS_DA_OP_OKNOENT;
> + if (args->flags & ATTR_ALLOC)
> + args->op_flags |= XFS_DA_OP_ALLOCVAL;
>
> - lock_mode = xfs_ilock_attr_map_shared(ip);
> - error = xfs_attr_get_ilocked(ip, &args);
> - xfs_iunlock(ip, lock_mode);
> - *valuelenp = args.valuelen;
> + lock_mode = xfs_ilock_attr_map_shared(args->dp);
> + error = xfs_attr_get_ilocked(args->dp, args);
> + xfs_iunlock(args->dp, lock_mode);
>
> /* on error, we have to clean up allocated value buffers */
> - if (error) {
> - if (flags & ATTR_ALLOC) {
> - kmem_free(args.value);
> - *value = NULL;
> - }
> - return error;
> + if (error && (args->flags & ATTR_ALLOC)) {
> + kmem_free(args->value);
> + args->value = NULL;
> }
> - *value = args.value;
> - return 0;
> + return error;
> }
>
> /*
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 07ca543db831..be77d13a2902 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -146,9 +146,7 @@ int xfs_attr_list_int_ilocked(struct xfs_attr_list_context *);
> int xfs_attr_list_int(struct xfs_attr_list_context *);
> int xfs_inode_hasattr(struct xfs_inode *ip);
> int xfs_attr_get_ilocked(struct xfs_inode *ip, struct xfs_da_args *args);
> -int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name,
> - size_t namelen, unsigned char **value, int *valuelenp,
> - int flags);
> +int xfs_attr_get(struct xfs_da_args *args);
> int xfs_attr_set(struct xfs_da_args *args);
> int xfs_attr_set_args(struct xfs_da_args *args);
> int xfs_attr_remove_args(struct xfs_da_args *args);
> diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
> index 8e2a0469e6dc..a3c7f86a13e7 100644
> --- a/fs/xfs/xfs_acl.c
> +++ b/fs/xfs/xfs_acl.c
> @@ -120,34 +120,31 @@ xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
> struct posix_acl *
> xfs_get_acl(struct inode *inode, int type)
> {
> - struct xfs_inode *ip = XFS_I(inode);
> - struct posix_acl *acl = NULL;
> - struct xfs_acl *xfs_acl = NULL;
> - unsigned char *ea_name;
> - int error;
> - int len;
> + struct xfs_inode *ip = XFS_I(inode);
> + struct xfs_mount *mp = ip->i_mount;
> + struct posix_acl *acl = NULL;
> + struct xfs_da_args args = {
> + .dp = ip,
> + .flags = ATTR_ALLOC | ATTR_ROOT,
> + .valuelen = XFS_ACL_MAX_SIZE(mp),
> + };
> + int error;
>
> trace_xfs_get_acl(ip);
>
> switch (type) {
> case ACL_TYPE_ACCESS:
> - ea_name = SGI_ACL_FILE;
> + args.name = SGI_ACL_FILE;
> break;
> case ACL_TYPE_DEFAULT:
> - ea_name = SGI_ACL_DEFAULT;
> + args.name = SGI_ACL_DEFAULT;
> break;
> default:
> BUG();
> }
> + args.namelen = strlen(args.name);
>
> - /*
> - * If we have a cached ACLs value just return it, not need to
> - * go out to the disk.
> - */
> - len = XFS_ACL_MAX_SIZE(ip->i_mount);
> - error = xfs_attr_get(ip, ea_name, strlen(ea_name),
> - (unsigned char **)&xfs_acl, &len,
> - ATTR_ALLOC | ATTR_ROOT);
> + error = xfs_attr_get(&args);
> if (error) {
> /*
> * If the attribute doesn't exist make sure we have a negative
> @@ -156,9 +153,9 @@ xfs_get_acl(struct inode *inode, int type)
> if (error != -ENOATTR)
> acl = ERR_PTR(error);
> } else {
> - acl = xfs_acl_from_disk(ip->i_mount, xfs_acl, len,
> - XFS_ACL_MAX_ENTRIES(ip->i_mount));
> - kmem_free(xfs_acl);
> + acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
> + XFS_ACL_MAX_ENTRIES(mp));
> + kmem_free(args.value);
> }
> return acl;
> }
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 44d97a8ceb4b..75b8fa7da1c9 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -355,27 +355,32 @@ xfs_attrmulti_attr_get(
> uint32_t *len,
> uint32_t flags)
> {
> - unsigned char *kbuf;
> - int error = -EFAULT;
> - size_t namelen;
> + struct xfs_da_args args = {
> + .dp = XFS_I(inode),
> + .flags = flags,
> + .name = name,
> + .namelen = strlen(name),
> + .valuelen = *len,
> + };
> + int error;
>
> if (*len > XFS_XATTR_SIZE_MAX)
> return -EINVAL;
> - kbuf = kmem_zalloc_large(*len, 0);
> - if (!kbuf)
> +
> + args.value = kmem_zalloc_large(*len, 0);
> + if (!args.value)
> return -ENOMEM;
>
> - namelen = strlen(name);
> - error = xfs_attr_get(XFS_I(inode), name, namelen, &kbuf, (int *)len,
> - flags);
> + error = xfs_attr_get(&args);
> if (error)
> goto out_kfree;
>
> - if (copy_to_user(ubuf, kbuf, *len))
> + *len = args.valuelen;
> + if (copy_to_user(ubuf, args.value, args.valuelen))
> error = -EFAULT;
>
> out_kfree:
> - kmem_free(kbuf);
> + kmem_free(args.value);
> return error;
> }
>
> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
> index 09f967f97699..b3ce5e8777f9 100644
> --- a/fs/xfs/xfs_xattr.c
> +++ b/fs/xfs/xfs_xattr.c
> @@ -21,22 +21,24 @@ static int
> xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
> struct inode *inode, const char *name, void *value, size_t size)
> {
> - int xflags = handler->flags;
> - struct xfs_inode *ip = XFS_I(inode);
> - int error, asize = size;
> - size_t namelen = strlen(name);
> + struct xfs_da_args args = {
> + .dp = XFS_I(inode),
> + .flags = handler->flags,
> + .name = name,
> + .namelen = strlen(name),
> + .value = value,
> + .valuelen = size,
> + };
> + int error;
>
> /* Convert Linux syscall to XFS internal ATTR flags */
> - if (!size) {
> - xflags |= ATTR_KERNOVAL;
> - value = NULL;
> - }
> + if (!size)
> + args.flags |= ATTR_KERNOVAL;
>
> - error = xfs_attr_get(ip, name, namelen, (unsigned char **)&value,
> - &asize, xflags);
> + error = xfs_attr_get(&args);
> if (error)
> return error;
> - return asize;
> + return args.valuelen;
> }
>
> void
> --
> 2.24.1
>