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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 /fs/namespace.c
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 'fs/namespace.c')
-rw-r--r--fs/namespace.c25
1 files changed, 9 insertions, 16 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 931228d8518a..1a1ed2528f47 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -997,17 +997,15 @@ struct vfsmount *vfs_kern_mount(struct file_system_type *type,
int ret = 0;
if (!type)
- return ERR_PTR(-ENODEV);
+ return ERR_PTR(-EINVAL);
fc = fs_context_for_mount(type, flags);
if (IS_ERR(fc))
return ERR_CAST(fc);
- if (name) {
- fc->source = kstrdup(name, GFP_KERNEL);
- if (!fc->source)
- ret = -ENOMEM;
- }
+ if (name)
+ ret = vfs_parse_fs_string(fc, "source",
+ name, strlen(name));
if (!ret)
ret = parse_monolithic_mount_data(fc, data);
if (!ret)
@@ -2611,16 +2609,11 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
if (IS_ERR(fc))
return PTR_ERR(fc);
- if (subtype) {
- fc->subtype = kstrdup(subtype, GFP_KERNEL);
- if (!fc->subtype)
- err = -ENOMEM;
- }
- if (!err && name) {
- fc->source = kstrdup(name, GFP_KERNEL);
- if (!fc->source)
- err = -ENOMEM;
- }
+ if (subtype)
+ err = vfs_parse_fs_string(fc, "subtype",
+ subtype, strlen(subtype));
+ if (!err && name)
+ err = vfs_parse_fs_string(fc, "source", name, strlen(name));
if (!err)
err = parse_monolithic_mount_data(fc, data);
if (!err)