diff options
| author | David Howells <dhowells@redhat.com> | 2019-03-21 12:22:36 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-09-05 21:34:23 +0300 |
| commit | 43ce4c1feadbc84c772518a2d1974f6ba1b15089 (patch) | |
| tree | e3bc42b51b6c0ca84b4a7c99f676999ed0bf892f | |
| parent | 0f071004109d9c8de7023b9a64fa2ba3fa87cbed (diff) | |
| download | linux-43ce4c1feadbc84c772518a2d1974f6ba1b15089.tar.xz | |
vfs: Add a single-or-reconfig keying to vfs_get_super()
Add an additional keying mode to vfs_get_super() to indicate that only a
single superblock should exist in the system, and that, if it does, further
mounts should invoke reconfiguration upon it.
This allows mount_single() to be replaced.
[Fix by Eric Biggers folded in]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/super.c | 35 | ||||
| -rw-r--r-- | include/linux/fs_context.h | 4 |
2 files changed, 32 insertions, 7 deletions
diff --git a/fs/super.c b/fs/super.c index da223b4cfbca..beaf076d9733 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1160,9 +1160,11 @@ int vfs_get_super(struct fs_context *fc, { int (*test)(struct super_block *, struct fs_context *); struct super_block *sb; + int err; switch (keying) { case vfs_get_single_super: + case vfs_get_single_reconf_super: test = test_single_super; break; case vfs_get_keyed_super: @@ -1180,18 +1182,29 @@ int vfs_get_super(struct fs_context *fc, return PTR_ERR(sb); if (!sb->s_root) { - int err = fill_super(sb, fc); - if (err) { - deactivate_locked_super(sb); - return err; - } + err = fill_super(sb, fc); + if (err) + goto error; sb->s_flags |= SB_ACTIVE; + fc->root = dget(sb->s_root); + } else { + fc->root = dget(sb->s_root); + if (keying == vfs_get_single_reconf_super) { + err = reconfigure_super(fc); + if (err < 0) { + dput(fc->root); + fc->root = NULL; + goto error; + } + } } - BUG_ON(fc->root); - fc->root = dget(sb->s_root); return 0; + +error: + deactivate_locked_super(sb); + return err; } EXPORT_SYMBOL(vfs_get_super); @@ -1211,6 +1224,14 @@ int get_tree_single(struct fs_context *fc, } EXPORT_SYMBOL(get_tree_single); +int get_tree_single_reconf(struct fs_context *fc, + int (*fill_super)(struct super_block *sb, + struct fs_context *fc)) +{ + return vfs_get_super(fc, vfs_get_single_reconf_super, fill_super); +} +EXPORT_SYMBOL(get_tree_single_reconf); + int get_tree_keyed(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc), diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h index 84a5eaa09f19..0424df7f6e6b 100644 --- a/include/linux/fs_context.h +++ b/include/linux/fs_context.h @@ -141,6 +141,7 @@ extern void put_fs_context(struct fs_context *fc); */ enum vfs_get_super_keying { vfs_get_single_super, /* Only one such superblock may exist */ + vfs_get_single_reconf_super, /* As above, but reconfigure if it exists */ vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */ vfs_get_independent_super, /* Multiple independent superblocks may exist */ }; @@ -155,6 +156,9 @@ extern int get_tree_nodev(struct fs_context *fc, extern int get_tree_single(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc)); +extern int get_tree_single_reconf(struct fs_context *fc, + int (*fill_super)(struct super_block *sb, + struct fs_context *fc)); extern int get_tree_keyed(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc), |