From: Daniel Xu <dxu@dxuuu.xyz>
To: cgroups@vger.kernel.org, tj@kernel.org, lizefan@huawei.com,
hannes@cmpxchg.org
Cc: Daniel Xu <dxu@dxuuu.xyz>,
shakeelb@google.com, linux-kernel@vger.kernel.org,
gregkh@linuxfoundation.org, kernel-team@fb.com
Subject: [PATCH v2 2/4] kernfs: Add removed_size out param for simple_xattr_set
Date: Thu, 5 Mar 2020 13:16:30 -0800 [thread overview]
Message-ID: <20200305211632.15369-3-dxu@dxuuu.xyz> (raw)
In-Reply-To: <20200305211632.15369-1-dxu@dxuuu.xyz>
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.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
---
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 d0f7a5abd9a9..5f10ae95fbfa 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 0d3c9b4d1914..e13265e65871 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -860,6 +860,7 @@ 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;
@@ -868,7 +869,8 @@ 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;
@@ -895,8 +897,12 @@ 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;
}
@@ -908,6 +914,9 @@ 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 6dad031be3c2..4cf6e11f4a3c 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -102,7 +102,8 @@ 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 aad3ba74b0e9..f47347cb30f6 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3243,7 +3243,7 @@ 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 = {
--
2.21.1
next prev parent reply other threads:[~2020-03-05 21:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-05 21:16 [PATCH v2 0/4] Support user xattrs in cgroupfs Daniel Xu
2020-03-05 21:16 ` [PATCH v2 1/4] kernfs: kvmalloc xattr value instead of kmalloc Daniel Xu
2020-03-06 8:49 ` Joe Perches
2020-03-06 9:37 ` Greg KH
2020-03-09 18:21 ` Daniel Xu
2020-03-09 19:41 ` Joe Perches
2020-03-09 19:51 ` Tejun Heo
2020-03-09 19:58 ` Joe Perches
2020-03-09 20:05 ` Tejun Heo
2020-03-10 19:40 ` Shakeel Butt
2020-03-10 20:40 ` Daniel Xu
2020-03-10 20:41 ` Shakeel Butt
2020-03-05 21:16 ` Daniel Xu [this message]
2020-03-10 18:20 ` [PATCH v2 2/4] kernfs: Add removed_size out param for simple_xattr_set Daniel Xu
2020-03-05 21:16 ` [PATCH v2 3/4] kernfs: Add option to enable user xattrs Daniel Xu
2020-03-05 21:16 ` [PATCH v2 4/4] cgroupfs: Support " Daniel Xu
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