From 5de75970c9fd7220e394b76e6d20fbafa1369b5a Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 8 Aug 2023 21:30:59 -0700 Subject: xattr: simple_xattr_set() return old_xattr to be freed tmpfs wants to support limited user extended attributes, but kernfs (or cgroupfs, the only kernfs with KERNFS_ROOT_SUPPORT_USER_XATTR) already supports user extended attributes through simple xattrs: but limited by a policy (128KiB per inode) too liberal to be used on tmpfs. To allow a different limiting policy for tmpfs, without affecting the policy for kernfs, change simple_xattr_set() to return the replaced or removed xattr (if any), leaving the caller to update their accounting then free the xattr (by simple_xattr_free(), renamed from the static free_simple_xattr()). Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Reviewed-by: Christian Brauner Reviewed-by: Carlos Maiolino Message-Id: <158c6585-2aa7-d4aa-90ff-f7c3f8fe407c@google.com> Signed-off-by: Christian Brauner --- fs/kernfs/inode.c | 46 +++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 17 deletions(-) (limited to 'fs/kernfs') diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index b22b74d1a115..fec5d5f78f07 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -306,11 +306,17 @@ int kernfs_xattr_get(struct kernfs_node *kn, const char *name, int kernfs_xattr_set(struct kernfs_node *kn, const char *name, const void *value, size_t size, int flags) { + struct simple_xattr *old_xattr; struct kernfs_iattrs *attrs = kernfs_iattrs(kn); if (!attrs) return -ENOMEM; - return simple_xattr_set(&attrs->xattrs, name, value, size, flags, NULL); + old_xattr = simple_xattr_set(&attrs->xattrs, name, value, size, flags); + if (IS_ERR(old_xattr)) + return PTR_ERR(old_xattr); + + simple_xattr_free(old_xattr); + return 0; } static int kernfs_vfs_xattr_get(const struct xattr_handler *handler, @@ -342,7 +348,7 @@ static int kernfs_vfs_user_xattr_add(struct kernfs_node *kn, { atomic_t *sz = &kn->iattr->user_xattr_size; atomic_t *nr = &kn->iattr->nr_user_xattrs; - ssize_t removed_size; + struct simple_xattr *old_xattr; int ret; if (atomic_inc_return(nr) > KERNFS_MAX_USER_XATTRS) { @@ -355,13 +361,18 @@ static int kernfs_vfs_user_xattr_add(struct kernfs_node *kn, goto dec_size_out; } - ret = simple_xattr_set(xattrs, full_name, value, size, flags, - &removed_size); - - if (!ret && removed_size >= 0) - size = removed_size; - else if (!ret) + old_xattr = simple_xattr_set(xattrs, full_name, value, size, flags); + if (!old_xattr) return 0; + + if (IS_ERR(old_xattr)) { + ret = PTR_ERR(old_xattr); + goto dec_size_out; + } + + ret = 0; + size = old_xattr->size; + simple_xattr_free(old_xattr); dec_size_out: atomic_sub(size, sz); dec_count_out: @@ -376,18 +387,19 @@ static int kernfs_vfs_user_xattr_rm(struct kernfs_node *kn, { atomic_t *sz = &kn->iattr->user_xattr_size; atomic_t *nr = &kn->iattr->nr_user_xattrs; - ssize_t removed_size; - int ret; + struct simple_xattr *old_xattr; - ret = simple_xattr_set(xattrs, full_name, value, size, flags, - &removed_size); + old_xattr = simple_xattr_set(xattrs, full_name, value, size, flags); + if (!old_xattr) + return 0; - if (removed_size >= 0) { - atomic_sub(removed_size, sz); - atomic_dec(nr); - } + if (IS_ERR(old_xattr)) + return PTR_ERR(old_xattr); - return ret; + atomic_sub(old_xattr->size, sz); + atomic_dec(nr); + simple_xattr_free(old_xattr); + return 0; } static int kernfs_vfs_user_xattr_set(const struct xattr_handler *handler, -- cgit v1.2.3