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authorDavid Howells <dhowells@redhat.com>2018-11-01 23:07:25 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2019-02-28 03:29:26 -0500
commit3e1aeb00e6d132efc151dacc062b38269bc9eccc (patch)
treed6cb75c4e0540cdd94e381c2afcacd6d7142fb30 /include/linux/fs.h
parent846e56621897a63966b7f03a70be29060394c363 (diff)
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.h')
-rw-r--r--include/linux/fs.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8d578a9e1e8c..cf6e9ea161eb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -62,6 +62,7 @@ struct iov_iter;
struct fscrypt_info;
struct fscrypt_operations;
struct fs_context;
+struct fs_parameter_description;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -2175,6 +2176,7 @@ struct file_system_type {
#define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
int (*init_fs_context)(struct fs_context *);
+ const struct fs_parameter_description *parameters;
struct dentry *(*mount) (struct file_system_type *, int,
const char *, void *);
void (*kill_sb) (struct super_block *);