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Merge "Merge 84ab1277ce ("Merge tag 'v6.6-vfs.fs_context' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs") into android-mainline" into android-mainline

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This commit is contained in:
Treehugger Robot
2023-09-07 21:39:01 +00:00
parent bdf5a5a3ec a7c18443c5
commit 4a2fcc5509
5 changed files with 107 additions and 71 deletions
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fs/fs_context.c
+1
View File
@@ -692,6 +692,7 @@ void vfs_clean_context(struct fs_context *fc)
security_free_mnt_opts(&fc->security);
kfree(fc->source);
fc->source = NULL;
fc->exclusive = false;
fc->purpose = FS_CONTEXT_FOR_RECONFIGURE;
fc->phase = FS_CONTEXT_AWAITING_RECONF;
fs/fsopen.c
+71 -35
View File
@@ -209,6 +209,72 @@ err:
return ret;
}
static int vfs_cmd_create(struct fs_context *fc, bool exclusive)
{
struct super_block *sb;
int ret;
if (fc->phase != FS_CONTEXT_CREATE_PARAMS)
return -EBUSY;
if (!mount_capable(fc))
return -EPERM;
/* require the new mount api */
if (exclusive && fc->ops == &legacy_fs_context_ops)
return -EOPNOTSUPP;
fc->phase = FS_CONTEXT_CREATING;
fc->exclusive = exclusive;
ret = vfs_get_tree(fc);
if (ret) {
fc->phase = FS_CONTEXT_FAILED;
return ret;
}
sb = fc->root->d_sb;
ret = security_sb_kern_mount(sb);
if (unlikely(ret)) {
fc_drop_locked(fc);
fc->phase = FS_CONTEXT_FAILED;
return ret;
}
/* vfs_get_tree() callchains will have grabbed @s_umount */
up_write(&sb->s_umount);
fc->phase = FS_CONTEXT_AWAITING_MOUNT;
return 0;
}
static int vfs_cmd_reconfigure(struct fs_context *fc)
{
struct super_block *sb;
int ret;
if (fc->phase != FS_CONTEXT_RECONF_PARAMS)
return -EBUSY;
fc->phase = FS_CONTEXT_RECONFIGURING;
sb = fc->root->d_sb;
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
fc->phase = FS_CONTEXT_FAILED;
return -EPERM;
}
down_write(&sb->s_umount);
ret = reconfigure_super(fc);
up_write(&sb->s_umount);
if (ret) {
fc->phase = FS_CONTEXT_FAILED;
return ret;
}
vfs_clean_context(fc);
return 0;
}
/*
* Check the state and apply the configuration. Note that this function is
* allowed to 'steal' the value by setting param->xxx to NULL before returning.
@@ -216,7 +282,6 @@ err:
static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
struct fs_parameter *param)
{
struct super_block *sb;
int ret;
ret = finish_clean_context(fc);
@@ -224,39 +289,11 @@ static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
return ret;
switch (cmd) {
case FSCONFIG_CMD_CREATE:
if (fc->phase != FS_CONTEXT_CREATE_PARAMS)
return -EBUSY;
if (!mount_capable(fc))
return -EPERM;
fc->phase = FS_CONTEXT_CREATING;
ret = vfs_get_tree(fc);
if (ret)
break;
sb = fc->root->d_sb;
ret = security_sb_kern_mount(sb);
if (unlikely(ret)) {
fc_drop_locked(fc);
break;
}
up_write(&sb->s_umount);
fc->phase = FS_CONTEXT_AWAITING_MOUNT;
return 0;
return vfs_cmd_create(fc, false);
case FSCONFIG_CMD_CREATE_EXCL:
return vfs_cmd_create(fc, true);
case FSCONFIG_CMD_RECONFIGURE:
if (fc->phase != FS_CONTEXT_RECONF_PARAMS)
return -EBUSY;
fc->phase = FS_CONTEXT_RECONFIGURING;
sb = fc->root->d_sb;
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
ret = -EPERM;
break;
}
down_write(&sb->s_umount);
ret = reconfigure_super(fc);
up_write(&sb->s_umount);
if (ret)
break;
vfs_clean_context(fc);
return 0;
return vfs_cmd_reconfigure(fc);
default:
if (fc->phase != FS_CONTEXT_CREATE_PARAMS &&
fc->phase != FS_CONTEXT_RECONF_PARAMS)
@@ -264,8 +301,6 @@ static int vfs_fsconfig_locked(struct fs_context *fc, int cmd,
return vfs_parse_fs_param(fc, param);
}
fc->phase = FS_CONTEXT_FAILED;
return ret;
}
/**
@@ -353,6 +388,7 @@ SYSCALL_DEFINE5(fsconfig,
return -EINVAL;
break;
case FSCONFIG_CMD_CREATE:
case FSCONFIG_CMD_CREATE_EXCL:
case FSCONFIG_CMD_RECONFIGURE:
if (_key || _value || aux)
return -EINVAL;
fs/super.c
+32 -32
View File
@@ -546,17 +546,31 @@ bool mount_capable(struct fs_context *fc)
* @test: Comparison callback
* @set: Setup callback
*
* Find or create a superblock using the parameters stored in the filesystem
* context and the two callback functions.
* Create a new superblock or find an existing one.
*
* If an extant superblock is matched, then that will be returned with an
* elevated reference count that the caller must transfer or discard.
* The @test callback is used to find a matching existing superblock.
* Whether or not the requested parameters in @fc are taken into account
* is specific to the @test callback that is used. They may even be
* completely ignored.
*
* If an extant superblock is matched, it will be returned unless:
*
* (1) the namespace the filesystem context @fc and the extant
* superblock's namespace differ
*
* (2) the filesystem context @fc has requested that reusing an extant
* superblock is not allowed
*
* In both cases EBUSY will be returned.
*
* If no match is made, a new superblock will be allocated and basic
* initialisation will be performed (s_type, s_fs_info and s_id will be set and
* the set() callback will be invoked), the superblock will be published and it
* will be returned in a partially constructed state with SB_BORN and SB_ACTIVE
* as yet unset.
* initialisation will be performed (s_type, s_fs_info and s_id will be
* set and the @set callback will be invoked), the superblock will be
* published and it will be returned in a partially constructed state
* with SB_BORN and SB_ACTIVE as yet unset.
*
* Return: On success, an extant or newly created superblock is
* returned. On failure an error pointer is returned.
*/
struct super_block *sget_fc(struct fs_context *fc,
int (*test)(struct super_block *, struct fs_context *),
@@ -603,9 +617,13 @@ retry:
return s;
share_extant_sb:
if (user_ns != old->s_user_ns) {
if (user_ns != old->s_user_ns || fc->exclusive) {
spin_unlock(&sb_lock);
destroy_unused_super(s);
if (fc->exclusive)
warnfc(fc, "reusing existing filesystem not allowed");
else
warnfc(fc, "reusing existing filesystem in another namespace not allowed");
return ERR_PTR(-EBUSY);
}
if (!grab_super(old))
@@ -1136,7 +1154,7 @@ static int test_single_super(struct super_block *s, struct fs_context *fc)
return 1;
}
static int vfs_get_super(struct fs_context *fc, bool reconf,
static int vfs_get_super(struct fs_context *fc,
int (*test)(struct super_block *, struct fs_context *),
int (*fill_super)(struct super_block *sb,
struct fs_context *fc))
@@ -1154,19 +1172,9 @@ static int vfs_get_super(struct fs_context *fc, bool reconf,
goto error;
sb->s_flags |= SB_ACTIVE;
fc->root = dget(sb->s_root);
} else {
fc->root = dget(sb->s_root);
if (reconf) {
err = reconfigure_super(fc);
if (err < 0) {
dput(fc->root);
fc->root = NULL;
goto error;
}
}
}
fc->root = dget(sb->s_root);
return 0;
error:
@@ -1178,7 +1186,7 @@ int get_tree_nodev(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc))
{
return vfs_get_super(fc, false, NULL, fill_super);
return vfs_get_super(fc, NULL, fill_super);
}
EXPORT_SYMBOL(get_tree_nodev);
@@ -1186,25 +1194,17 @@ int get_tree_single(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc))
{
return vfs_get_super(fc, false, test_single_super, fill_super);
return vfs_get_super(fc, test_single_super, fill_super);
}
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, true, test_single_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),
void *key)
{
fc->s_fs_info = key;
return vfs_get_super(fc, false, test_keyed_super, fill_super);
return vfs_get_super(fc, test_keyed_super, fill_super);
}
EXPORT_SYMBOL(get_tree_keyed);
include/linux/fs_context.h
+1 -3
View File
@@ -109,6 +109,7 @@ struct fs_context {
bool need_free:1; /* Need to call ops->free() */
bool global:1; /* Goes into &init_user_ns */
bool oldapi:1; /* Coming from mount(2) */
bool exclusive:1; /* create new superblock, reject existing one */
};
struct fs_context_operations {
@@ -150,9 +151,6 @@ 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),
include/uapi/linux/mount.h
+2 -1
View File
@@ -100,8 +100,9 @@ enum fsconfig_command {
FSCONFIG_SET_PATH = 3, /* Set parameter, supplying an object by path */
FSCONFIG_SET_PATH_EMPTY = 4, /* Set parameter, supplying an object by (empty) path */
FSCONFIG_SET_FD = 5, /* Set parameter, supplying an object by fd */
FSCONFIG_CMD_CREATE = 6, /* Invoke superblock creation */
FSCONFIG_CMD_CREATE = 6, /* Create new or reuse existing superblock */
FSCONFIG_CMD_RECONFIGURE = 7, /* Invoke superblock reconfiguration */
FSCONFIG_CMD_CREATE_EXCL = 8, /* Create new superblock, fail if reusing existing superblock */
};
/*