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| author | Hugh Dickins <hughd@google.com> | 2023-08-09 07:30:59 +0300 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2023-08-09 10:15:51 +0300 |
| commit | 5de75970c9fd7220e394b76e6d20fbafa1369b5a (patch) | |
| tree | eb0b3a67a96b975840c0600a70cbbf4dab39d0fc /fs/kernfs | |
| parent | 0200679fc7953177941e41c2a4241d0b6c2c5de8 (diff) | |
| download | linux-5de75970c9fd7220e394b76e6d20fbafa1369b5a.tar.xz | |
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 <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Message-Id: <158c6585-2aa7-d4aa-90ff-f7c3f8fe407c@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/kernfs')
| -rw-r--r-- | fs/kernfs/inode.c | 46 |
1 files changed, 29 insertions, 17 deletions
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, |