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authorDavid Howells <dhowells@redhat.com>2018-11-02 02:07:25 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2019-02-28 11:29:26 +0300
commit3e1aeb00e6d132efc151dacc062b38269bc9eccc (patch)
treed6cb75c4e0540cdd94e381c2afcacd6d7142fb30 /include/linux/fs_context.h
parent846e56621897a63966b7f03a70be29060394c363 (diff)
downloadlinux-3e1aeb00e6d132efc151dacc062b38269bc9eccc.tar.xz
vfs: Implement a filesystem superblock creation/configuration context
[AV - unfuck kern_mount_data(); we want non-NULL ->mnt_ns on long-living mounts] [AV - reordering fs/namespace.c is badly overdue, but let's keep it separate from that series] [AV - drop simple_pin_fs() change] [AV - clean vfs_kern_mount() failure exits up] Implement a filesystem context concept to be used during superblock creation for mount and superblock reconfiguration for remount. The mounting procedure then becomes: (1) Allocate new fs_context context. (2) Configure the context. (3) Create superblock. (4) Query the superblock. (5) Create a mount for the superblock. (6) Destroy the context. Rather than calling fs_type->mount(), an fs_context struct is created and fs_type->init_fs_context() is called to set it up. Pointers exist for the filesystem and LSM to hang their private data off. A set of operations has to be set by ->init_fs_context() to provide freeing, duplication, option parsing, binary data parsing, validation, mounting and superblock filling. Legacy filesystems are supported by the provision of a set of legacy fs_context operations that build up a list of mount options and then invoke fs_type->mount() from within the fs_context ->get_tree() operation. This allows all filesystems to be accessed using fs_context. It should be noted that, whilst this patch adds a lot of lines of code, there is quite a bit of duplication with existing code that can be eliminated should all filesystems be converted over. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/fs_context.h')
-rw-r--r--include/linux/fs_context.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index d5ff3b0bc28d..d794b04e9fbb 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -92,6 +92,7 @@ struct fs_context {
struct fs_context_operations {
void (*free)(struct fs_context *fc);
+ int (*parse_param)(struct fs_context *fc, struct fs_parameter *param);
int (*parse_monolithic)(struct fs_context *fc, void *data);
int (*get_tree)(struct fs_context *fc);
int (*reconfigure)(struct fs_context *fc);
@@ -108,6 +109,10 @@ extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type,
struct dentry *reference);
+extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
+extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
+ const char *value, size_t v_size);
+extern int generic_parse_monolithic(struct fs_context *fc, void *data);
extern int vfs_get_tree(struct fs_context *fc);
extern void put_fs_context(struct fs_context *fc);