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authorAl Viro <viro@zeniv.linux.org.uk>2015-05-02 20:32:22 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2015-05-11 05:19:45 +0300
commit680baacbca69d18a6d7315374ad83d05ac9c0977 (patch)
treea69822ef5234d4a308b780ff51c5d9b77bd3a89b /fs/kernfs
parent46afd6f61cc33ae4b3a2aed4bb454d11d4114c27 (diff)
downloadlinux-680baacbca69d18a6d7315374ad83d05ac9c0977.tar.xz
new ->follow_link() and ->put_link() calling conventions
a) instead of storing the symlink body (via nd_set_link()) and returning an opaque pointer later passed to ->put_link(), ->follow_link() _stores_ that opaque pointer (into void * passed by address by caller) and returns the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic symlinks) and pointer to symlink body for normal symlinks. Stored pointer is ignored in all cases except the last one. Storing NULL for opaque pointer (or not storing it at all) means no call of ->put_link(). b) the body used to be passed to ->put_link() implicitly (via nameidata). Now only the opaque pointer is. In the cases when we used the symlink body to free stuff, ->follow_link() now should store it as opaque pointer in addition to returning it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/symlink.c22
1 files changed, 10 insertions, 12 deletions
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 8a198898e39a..3c7e799974a2 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -112,25 +112,23 @@ static int kernfs_getlink(struct dentry *dentry, char *path)
return error;
}
-static void *kernfs_iop_follow_link(struct dentry *dentry, struct nameidata *nd)
+static const char *kernfs_iop_follow_link(struct dentry *dentry, void **cookie, struct nameidata *nd)
{
int error = -ENOMEM;
unsigned long page = get_zeroed_page(GFP_KERNEL);
- if (page) {
- error = kernfs_getlink(dentry, (char *) page);
- if (error < 0)
- free_page((unsigned long)page);
+ if (!page)
+ return ERR_PTR(-ENOMEM);
+ error = kernfs_getlink(dentry, (char *)page);
+ if (unlikely(error < 0)) {
+ free_page((unsigned long)page);
+ return ERR_PTR(error);
}
- nd_set_link(nd, error ? ERR_PTR(error) : (char *)page);
- return NULL;
+ return *cookie = (char *)page;
}
-static void kernfs_iop_put_link(struct dentry *dentry, struct nameidata *nd,
- void *cookie)
+static void kernfs_iop_put_link(struct dentry *dentry, void *cookie)
{
- char *page = nd_get_link(nd);
- if (!IS_ERR(page))
- free_page((unsigned long)page);
+ free_page((unsigned long)cookie);
}
const struct inode_operations kernfs_symlink_iops = {