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authorAl Viro <viro@zeniv.linux.org.uk>2018-12-24 00:25:31 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2019-01-31 01:44:27 +0300
commite1a91586d5da6f879b6dd385a2e7227bf1653570 (patch)
treef7c6869c8307059a95a0c2688a88fecf5493b30e
parent8d0347f6c3a9d4953ddd636a31c6584da082e084 (diff)
downloadlinux-e1a91586d5da6f879b6dd385a2e7227bf1653570.tar.xz
fs_context flavour for submounts
This is an eventual replacement for vfs_submount() uses. Unlike the "mount" and "remount" cases, the users of that thing are not in VFS - they are buried in various ->d_automount() instances and rather than converting them all at once we introduce the (thankfully small and simple) infrastructure here and deal with the prospective users in afs, nfs, etc. parts of the series. Here we just introduce a new constructor (fs_context_for_submount()) along with the corresponding enum constant to be put into fc->purpose for those. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/fs_context.c10
-rw-r--r--include/linux/fs_context.h3
2 files changed, 13 insertions, 0 deletions
diff --git a/fs/fs_context.c b/fs/fs_context.c
index 5e2c3aba1dd8..2bd652b6e848 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -69,6 +69,9 @@ static struct fs_context *alloc_fs_context(struct file_system_type *fs_type,
case FS_CONTEXT_FOR_MOUNT:
fc->user_ns = get_user_ns(fc->cred->user_ns);
break;
+ case FS_CONTEXT_FOR_SUBMOUNT:
+ fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
+ break;
case FS_CONTEXT_FOR_RECONFIGURE:
/* We don't pin any namespaces as the superblock's
* subscriptions cannot be changed at this point.
@@ -106,6 +109,13 @@ struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
}
EXPORT_SYMBOL(fs_context_for_reconfigure);
+struct fs_context *fs_context_for_submount(struct file_system_type *type,
+ struct dentry *reference)
+{
+ return alloc_fs_context(type, reference, 0, 0, FS_CONTEXT_FOR_SUBMOUNT);
+}
+EXPORT_SYMBOL(fs_context_for_submount);
+
void fc_drop_locked(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 98772f882a3e..7feb018c7a9e 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -25,6 +25,7 @@ struct user_namespace;
enum fs_context_purpose {
FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */
+ FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */
FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */
};
@@ -61,6 +62,8 @@ extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type,
extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
unsigned int sb_flags,
unsigned int sb_flags_mask);
+extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type,
+ struct dentry *reference);
extern int vfs_get_tree(struct fs_context *fc);
extern void put_fs_context(struct fs_context *fc);