From 5afd90915008905f4b2479ac1a177e2121b0a891 Mon Sep 17 00:00:00 2001 From: Daniel Xu Date: Thu, 12 Mar 2020 13:03:15 -0700 Subject: [PATCH] UPSTREAM: kernfs: Add removed_size out param for simple_xattr_set This helps set up size accounting in the next commit. Without this out param, it's difficult to find out the removed xattr size without taking a lock for longer and walking the xattr linked list twice. Change-Id: I831978a8fd659665b025898c0aa3c4f364f798cf Signed-off-by: Daniel Xu Acked-by: Chris Down Reviewed-by: Greg Kroah-Hartman Signed-off-by: Tejun Heo --- fs/kernfs/inode.c | 2 +- fs/xattr.c | 11 ++++++++++- include/linux/xattr.h | 3 ++- mm/shmem.c | 2 +- 4 files changed, 14 insertions(+), 4 deletions(-) diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index d762f55f4c3e..f2b9da42a164 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -303,7 +303,7 @@ int kernfs_xattr_set(struct kernfs_node *kn, const char *name, if (!attrs) return -ENOMEM; - return simple_xattr_set(&attrs->xattrs, name, value, size, flags); + return simple_xattr_set(&attrs->xattrs, name, value, size, flags, NULL); } static int kernfs_vfs_xattr_get(const struct xattr_handler *handler, diff --git a/fs/xattr.c b/fs/xattr.c index b2855070757e..dc1ef6eb43e2 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -930,6 +930,7 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, * @value: value of the xattr. If %NULL, will remove the attribute. * @size: size of the new xattr * @flags: %XATTR_{CREATE|REPLACE} + * @removed_size: returns size of the removed xattr, -1 if none removed * * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; @@ -938,7 +939,8 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, * Returns 0 on success, -errno on failure. */ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, - const void *value, size_t size, int flags) + const void *value, size_t size, int flags, + ssize_t *removed_size) { struct simple_xattr *xattr; struct simple_xattr *new_xattr = NULL; @@ -965,8 +967,12 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, err = -EEXIST; } else if (new_xattr) { list_replace(&xattr->list, &new_xattr->list); + if (removed_size) + *removed_size = xattr->size; } else { list_del(&xattr->list); + if (removed_size) + *removed_size = xattr->size; } goto out; } @@ -978,6 +984,9 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, list_add(&new_xattr->list, &xattrs->head); xattr = NULL; } + + if (removed_size) + *removed_size = -1; out: spin_unlock(&xattrs->lock); if (xattr) { diff --git a/include/linux/xattr.h b/include/linux/xattr.h index 0d970fdc66e1..aecc330c1cc5 100644 --- a/include/linux/xattr.h +++ b/include/linux/xattr.h @@ -105,7 +105,8 @@ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size); int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, void *buffer, size_t size); int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, - const void *value, size_t size, int flags); + const void *value, size_t size, int flags, + ssize_t *removed_size); ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer, size_t size); void simple_xattr_list_add(struct simple_xattrs *xattrs, diff --git a/mm/shmem.c b/mm/shmem.c index f7c04a91687b..edaa65d0aacb 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -3203,7 +3203,7 @@ static int shmem_xattr_handler_set(const struct xattr_handler *handler, struct shmem_inode_info *info = SHMEM_I(inode); name = xattr_full_name(handler, name); - return simple_xattr_set(&info->xattrs, name, value, size, flags); + return simple_xattr_set(&info->xattrs, name, value, size, flags, NULL); } static const struct xattr_handler shmem_security_xattr_handler = {