From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/super.c | 641 ++++++++++++++++++++++++++++++++++++++++-----------------
1 files changed, 447 insertions(+), 194 deletions(-)
diff --git a/kernel/fs/super.c b/kernel/fs/super.c
index 014ae9b..23ad90f 100644
--- a/kernel/fs/super.c
+++ b/kernel/fs/super.c
@@ -36,6 +36,8 @@
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
+#include <linux/fs_context.h>
+#include <uapi/linux/mount.h>
#include "internal.h"
static int thaw_super_locked(struct super_block *sb);
@@ -256,6 +258,8 @@
s->s_maxbytes = MAX_NON_LFS;
s->s_op = &default_op;
s->s_time_gran = 1000000000;
+ s->s_time_min = TIME64_MIN;
+ s->s_time_max = TIME64_MAX;
s->cleancache_poolid = CLEANCACHE_NO_POOL;
s->s_shrink.seeks = DEFAULT_SEEKS;
@@ -289,7 +293,7 @@
WARN_ON(s->s_inode_lru.node);
WARN_ON(!list_empty(&s->s_mounts));
security_sb_free(s);
- fscrypt_sb_free(s);
+ fscrypt_destroy_keyring(s);
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
call_rcu(&s->rcu, destroy_super_rcu);
@@ -357,7 +361,7 @@
*/
void deactivate_super(struct super_block *s)
{
- if (!atomic_add_unless(&s->s_active, -1, 1)) {
+ if (!atomic_add_unless(&s->s_active, -1, 1)) {
down_write(&s->s_umount);
deactivate_locked_super(s);
}
@@ -444,10 +448,13 @@
sync_filesystem(sb);
sb->s_flags &= ~SB_ACTIVE;
- fsnotify_unmount_inodes(sb);
cgroup_writeback_umount();
+ /* evict all inodes with zero refcount */
evict_inodes(sb);
+ /* only nonzero refcount inodes can have marks */
+ fsnotify_sb_delete(sb);
+ fscrypt_destroy_keyring(sb);
if (sb->s_dio_done_wq) {
destroy_workqueue(sb->s_dio_done_wq);
@@ -476,29 +483,115 @@
EXPORT_SYMBOL(generic_shutdown_super);
+bool mount_capable(struct fs_context *fc)
+{
+ if (!(fc->fs_type->fs_flags & FS_USERNS_MOUNT))
+ return capable(CAP_SYS_ADMIN);
+ else
+ return ns_capable(fc->user_ns, CAP_SYS_ADMIN);
+}
+
/**
- * sget_userns - find or create a superblock
- * @type: filesystem type superblock should belong to
- * @test: comparison callback
- * @set: setup callback
- * @flags: mount flags
- * @user_ns: User namespace for the super_block
- * @data: argument to each of them
+ * sget_fc - Find or create a superblock
+ * @fc: Filesystem context.
+ * @test: Comparison callback
+ * @set: Setup callback
+ *
+ * Find or create a superblock using the parameters stored in the filesystem
+ * context and the two callback functions.
+ *
+ * If an extant superblock is matched, then that will be returned with an
+ * elevated reference count that the caller must transfer or discard.
+ *
+ * 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.
*/
-struct super_block *sget_userns(struct file_system_type *type,
+struct super_block *sget_fc(struct fs_context *fc,
+ int (*test)(struct super_block *, struct fs_context *),
+ int (*set)(struct super_block *, struct fs_context *))
+{
+ struct super_block *s = NULL;
+ struct super_block *old;
+ struct user_namespace *user_ns = fc->global ? &init_user_ns : fc->user_ns;
+ int err;
+
+retry:
+ spin_lock(&sb_lock);
+ if (test) {
+ hlist_for_each_entry(old, &fc->fs_type->fs_supers, s_instances) {
+ if (test(old, fc))
+ goto share_extant_sb;
+ }
+ }
+ if (!s) {
+ spin_unlock(&sb_lock);
+ s = alloc_super(fc->fs_type, fc->sb_flags, user_ns);
+ if (!s)
+ return ERR_PTR(-ENOMEM);
+ goto retry;
+ }
+
+ s->s_fs_info = fc->s_fs_info;
+ err = set(s, fc);
+ if (err) {
+ s->s_fs_info = NULL;
+ spin_unlock(&sb_lock);
+ destroy_unused_super(s);
+ return ERR_PTR(err);
+ }
+ fc->s_fs_info = NULL;
+ s->s_type = fc->fs_type;
+ s->s_iflags |= fc->s_iflags;
+ strlcpy(s->s_id, s->s_type->name, sizeof(s->s_id));
+ list_add_tail(&s->s_list, &super_blocks);
+ hlist_add_head(&s->s_instances, &s->s_type->fs_supers);
+ spin_unlock(&sb_lock);
+ get_filesystem(s->s_type);
+ register_shrinker_prepared(&s->s_shrink);
+ return s;
+
+share_extant_sb:
+ if (user_ns != old->s_user_ns) {
+ spin_unlock(&sb_lock);
+ destroy_unused_super(s);
+ return ERR_PTR(-EBUSY);
+ }
+ if (!grab_super(old))
+ goto retry;
+ destroy_unused_super(s);
+ return old;
+}
+EXPORT_SYMBOL(sget_fc);
+
+/**
+ * sget - find or create a superblock
+ * @type: filesystem type superblock should belong to
+ * @test: comparison callback
+ * @set: setup callback
+ * @flags: mount flags
+ * @data: argument to each of them
+ */
+struct super_block *sget(struct file_system_type *type,
int (*test)(struct super_block *,void *),
int (*set)(struct super_block *,void *),
- int flags, struct user_namespace *user_ns,
+ int flags,
void *data)
{
+ struct user_namespace *user_ns = current_user_ns();
struct super_block *s = NULL;
struct super_block *old;
int err;
- if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) &&
- !(type->fs_flags & FS_USERNS_MOUNT) &&
- !capable(CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
+ /* We don't yet pass the user namespace of the parent
+ * mount through to here so always use &init_user_ns
+ * until that changes.
+ */
+ if (flags & SB_SUBMOUNT)
+ user_ns = &init_user_ns;
+
retry:
spin_lock(&sb_lock);
if (test) {
@@ -539,39 +632,6 @@
register_shrinker_prepared(&s->s_shrink);
return s;
}
-
-EXPORT_SYMBOL(sget_userns);
-
-/**
- * sget - find or create a superblock
- * @type: filesystem type superblock should belong to
- * @test: comparison callback
- * @set: setup callback
- * @flags: mount flags
- * @data: argument to each of them
- */
-struct super_block *sget(struct file_system_type *type,
- int (*test)(struct super_block *,void *),
- int (*set)(struct super_block *,void *),
- int flags,
- void *data)
-{
- struct user_namespace *user_ns = current_user_ns();
-
- /* We don't yet pass the user namespace of the parent
- * mount through to here so always use &init_user_ns
- * until that changes.
- */
- if (flags & SB_SUBMOUNT)
- user_ns = &init_user_ns;
-
- /* Ensure the requestor has permissions over the target filesystem */
- if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
-
- return sget_userns(type, test, set, flags, user_ns, data);
-}
-
EXPORT_SYMBOL(sget);
void drop_super(struct super_block *sb)
@@ -836,29 +896,36 @@
}
/**
- * do_remount_sb2 - asks filesystem to change mount options.
- * @mnt: mount we are looking at
- * @sb: superblock in question
- * @sb_flags: revised superblock flags
- * @data: the rest of options
- * @force: whether or not to force the change
+ * reconfigure_super - asks filesystem to change superblock parameters
+ * @fc: The superblock and configuration
*
- * Alters the mount options of a mounted file system.
+ * Alters the configuration parameters of a live superblock.
*/
-int do_remount_sb2(struct vfsmount *mnt, struct super_block *sb, int sb_flags, void *data, int force)
+int reconfigure_super(struct fs_context *fc)
{
+ struct super_block *sb = fc->root->d_sb;
int retval;
- int remount_ro;
+ bool remount_ro = false;
+ bool remount_rw = false;
+ bool force = fc->sb_flags & SB_FORCE;
+ if (fc->sb_flags_mask & ~MS_RMT_MASK)
+ return -EINVAL;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
-#ifdef CONFIG_BLOCK
- if (!(sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev))
- return -EACCES;
-#endif
+ retval = security_sb_remount(sb, fc->security);
+ if (retval)
+ return retval;
- remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb);
+ if (fc->sb_flags_mask & SB_RDONLY) {
+#ifdef CONFIG_BLOCK
+ if (!(fc->sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev))
+ return -EACCES;
+#endif
+ remount_rw = !(fc->sb_flags & SB_RDONLY) && sb_rdonly(sb);
+ remount_ro = (fc->sb_flags & SB_RDONLY) && !sb_rdonly(sb);
+ }
if (remount_ro) {
if (!hlist_empty(&sb->s_pins)) {
@@ -869,13 +936,14 @@
return 0;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
- remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb);
+ remount_ro = !sb_rdonly(sb);
}
}
shrink_dcache_sb(sb);
- /* If we are remounting RDONLY and current sb is read/write,
- make sure there are no rw files opened */
+ /* If we are reconfiguring to RDONLY and current sb is read/write,
+ * make sure there are no files open for writing.
+ */
if (remount_ro) {
if (force) {
sb->s_readonly_remount = 1;
@@ -885,19 +953,18 @@
if (retval)
return retval;
}
+ } else if (remount_rw) {
+ /*
+ * We set s_readonly_remount here to protect filesystem's
+ * reconfigure code from writes from userspace until
+ * reconfigure finishes.
+ */
+ sb->s_readonly_remount = 1;
+ smp_wmb();
}
- if (mnt && sb->s_op->remount_fs2) {
- retval = sb->s_op->remount_fs2(mnt, sb, &sb_flags, data);
- if (retval) {
- if (!force)
- goto cancel_readonly;
- /* If forced remount, go ahead despite any errors */
- WARN(1, "forced remount of a %s fs returned %i\n",
- sb->s_type->name, retval);
- }
- } else if (sb->s_op->remount_fs) {
- retval = sb->s_op->remount_fs(sb, &sb_flags, data);
+ if (fc->ops->reconfigure) {
+ retval = fc->ops->reconfigure(fc);
if (retval) {
if (!force)
goto cancel_readonly;
@@ -906,7 +973,9 @@
sb->s_type->name, retval);
}
}
- sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (sb_flags & MS_RMT_MASK);
+
+ WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) |
+ (fc->sb_flags & fc->sb_flags_mask)));
/* Needs to be ordered wrt mnt_is_readonly() */
smp_wmb();
sb->s_readonly_remount = 0;
@@ -928,20 +997,20 @@
return retval;
}
-int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
-{
- return do_remount_sb2(NULL, sb, flags, data, force);
-}
-
static void do_emergency_remount_callback(struct super_block *sb)
{
down_write(&sb->s_umount);
if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&
!sb_rdonly(sb)) {
- /*
- * What lock protects sb->s_flags??
- */
- do_remount_sb(sb, SB_RDONLY, NULL, 1);
+ struct fs_context *fc;
+
+ fc = fs_context_for_reconfigure(sb->s_root,
+ SB_RDONLY | SB_FORCE, SB_RDONLY);
+ if (!IS_ERR(fc)) {
+ if (parse_monolithic_mount_data(fc, NULL) == 0)
+ (void)reconfigure_super(fc);
+ put_fs_context(fc);
+ }
}
up_write(&sb->s_umount);
}
@@ -1059,59 +1128,244 @@
}
EXPORT_SYMBOL(kill_litter_super);
-static int ns_test_super(struct super_block *sb, void *data)
+int set_anon_super_fc(struct super_block *sb, struct fs_context *fc)
{
- return sb->s_fs_info == data;
-}
-
-static int ns_set_super(struct super_block *sb, void *data)
-{
- sb->s_fs_info = data;
return set_anon_super(sb, NULL);
}
+EXPORT_SYMBOL(set_anon_super_fc);
-struct dentry *mount_ns(struct file_system_type *fs_type,
- int flags, void *data, void *ns, struct user_namespace *user_ns,
- int (*fill_super)(struct super_block *, void *, int))
+static int test_keyed_super(struct super_block *sb, struct fs_context *fc)
{
- struct super_block *sb;
-
- /* Don't allow mounting unless the caller has CAP_SYS_ADMIN
- * over the namespace.
- */
- if (!(flags & SB_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
-
- sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags,
- user_ns, ns);
- if (IS_ERR(sb))
- return ERR_CAST(sb);
-
- if (!sb->s_root) {
- int err;
- err = fill_super(sb, data, flags & SB_SILENT ? 1 : 0);
- if (err) {
- deactivate_locked_super(sb);
- return ERR_PTR(err);
- }
-
- sb->s_flags |= SB_ACTIVE;
- }
-
- return dget(sb->s_root);
+ return sb->s_fs_info == fc->s_fs_info;
}
-EXPORT_SYMBOL(mount_ns);
+static int test_single_super(struct super_block *s, struct fs_context *fc)
+{
+ return 1;
+}
+
+/**
+ * vfs_get_super - Get a superblock with a search key set in s_fs_info.
+ * @fc: The filesystem context holding the parameters
+ * @keying: How to distinguish superblocks
+ * @fill_super: Helper to initialise a new superblock
+ *
+ * Search for a superblock and create a new one if not found. The search
+ * criterion is controlled by @keying. If the search fails, a new superblock
+ * is created and @fill_super() is called to initialise it.
+ *
+ * @keying can take one of a number of values:
+ *
+ * (1) vfs_get_single_super - Only one superblock of this type may exist on the
+ * system. This is typically used for special system filesystems.
+ *
+ * (2) vfs_get_keyed_super - Multiple superblocks may exist, but they must have
+ * distinct keys (where the key is in s_fs_info). Searching for the same
+ * key again will turn up the superblock for that key.
+ *
+ * (3) vfs_get_independent_super - Multiple superblocks may exist and are
+ * unkeyed. Each call will get a new superblock.
+ *
+ * A permissions check is made by sget_fc() unless we're getting a superblock
+ * for a kernel-internal mount or a submount.
+ */
+int vfs_get_super(struct fs_context *fc,
+ enum vfs_get_super_keying keying,
+ int (*fill_super)(struct super_block *sb,
+ 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:
+ test = test_keyed_super;
+ break;
+ case vfs_get_independent_super:
+ test = NULL;
+ break;
+ default:
+ BUG();
+ }
+
+ sb = sget_fc(fc, test, set_anon_super_fc);
+ if (IS_ERR(sb))
+ return PTR_ERR(sb);
+
+ if (!sb->s_root) {
+ 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;
+ }
+ }
+ }
+
+ return 0;
+
+error:
+ deactivate_locked_super(sb);
+ return err;
+}
+EXPORT_SYMBOL(vfs_get_super);
+
+int get_tree_nodev(struct fs_context *fc,
+ int (*fill_super)(struct super_block *sb,
+ struct fs_context *fc))
+{
+ return vfs_get_super(fc, vfs_get_independent_super, fill_super);
+}
+EXPORT_SYMBOL(get_tree_nodev);
+
+int get_tree_single(struct fs_context *fc,
+ int (*fill_super)(struct super_block *sb,
+ struct fs_context *fc))
+{
+ return vfs_get_super(fc, vfs_get_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, 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),
+ void *key)
+{
+ fc->s_fs_info = key;
+ return vfs_get_super(fc, vfs_get_keyed_super, fill_super);
+}
+EXPORT_SYMBOL(get_tree_keyed);
#ifdef CONFIG_BLOCK
+
static int set_bdev_super(struct super_block *s, void *data)
{
s->s_bdev = data;
s->s_dev = s->s_bdev->bd_dev;
s->s_bdi = bdi_get(s->s_bdev->bd_bdi);
+ if (blk_queue_stable_writes(s->s_bdev->bd_disk->queue))
+ s->s_iflags |= SB_I_STABLE_WRITES;
return 0;
}
+
+static int set_bdev_super_fc(struct super_block *s, struct fs_context *fc)
+{
+ return set_bdev_super(s, fc->sget_key);
+}
+
+static int test_bdev_super_fc(struct super_block *s, struct fs_context *fc)
+{
+ return s->s_bdev == fc->sget_key;
+}
+
+/**
+ * get_tree_bdev - Get a superblock based on a single block device
+ * @fc: The filesystem context holding the parameters
+ * @fill_super: Helper to initialise a new superblock
+ */
+int get_tree_bdev(struct fs_context *fc,
+ int (*fill_super)(struct super_block *,
+ struct fs_context *))
+{
+ struct block_device *bdev;
+ struct super_block *s;
+ fmode_t mode = FMODE_READ | FMODE_EXCL;
+ int error = 0;
+
+ if (!(fc->sb_flags & SB_RDONLY))
+ mode |= FMODE_WRITE;
+
+ if (!fc->source)
+ return invalf(fc, "No source specified");
+
+ bdev = blkdev_get_by_path(fc->source, mode, fc->fs_type);
+ if (IS_ERR(bdev)) {
+ errorf(fc, "%s: Can't open blockdev", fc->source);
+ return PTR_ERR(bdev);
+ }
+
+ /* Once the superblock is inserted into the list by sget_fc(), s_umount
+ * will protect the lockfs code from trying to start a snapshot while
+ * we are mounting
+ */
+ mutex_lock(&bdev->bd_fsfreeze_mutex);
+ if (bdev->bd_fsfreeze_count > 0) {
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev);
+ blkdev_put(bdev, mode);
+ return -EBUSY;
+ }
+
+ fc->sb_flags |= SB_NOSEC;
+ fc->sget_key = bdev;
+ s = sget_fc(fc, test_bdev_super_fc, set_bdev_super_fc);
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ if (IS_ERR(s)) {
+ blkdev_put(bdev, mode);
+ return PTR_ERR(s);
+ }
+
+ if (s->s_root) {
+ /* Don't summarily change the RO/RW state. */
+ if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
+ warnf(fc, "%pg: Can't mount, would change RO state", bdev);
+ deactivate_locked_super(s);
+ blkdev_put(bdev, mode);
+ return -EBUSY;
+ }
+
+ /*
+ * s_umount nests inside bd_mutex during
+ * __invalidate_device(). blkdev_put() acquires
+ * bd_mutex and can't be called under s_umount. Drop
+ * s_umount temporarily. This is safe as we're
+ * holding an active reference.
+ */
+ up_write(&s->s_umount);
+ blkdev_put(bdev, mode);
+ down_write(&s->s_umount);
+ } else {
+ s->s_mode = mode;
+ snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
+ sb_set_blocksize(s, block_size(bdev));
+ error = fill_super(s, fc);
+ if (error) {
+ deactivate_locked_super(s);
+ return error;
+ }
+
+ s->s_flags |= SB_ACTIVE;
+ bdev->bd_super = s;
+ }
+
+ BUG_ON(fc->root);
+ fc->root = dget(s->s_root);
+ return 0;
+}
+EXPORT_SYMBOL(get_tree_bdev);
static int test_bdev_super(struct super_block *s, void *data)
{
@@ -1191,7 +1445,7 @@
error:
return ERR_PTR(error);
}
-EXPORT_SYMBOL(mount_bdev);
+EXPORT_SYMBOL_NS(mount_bdev, ANDROID_GKI_VFS_EXPORT_ONLY);
void kill_block_super(struct super_block *sb)
{
@@ -1205,7 +1459,7 @@
blkdev_put(bdev, mode | FMODE_EXCL);
}
-EXPORT_SYMBOL(kill_block_super);
+EXPORT_SYMBOL_NS(kill_block_super, ANDROID_GKI_VFS_EXPORT_ONLY);
#endif
struct dentry *mount_nodev(struct file_system_type *fs_type,
@@ -1228,6 +1482,31 @@
}
EXPORT_SYMBOL(mount_nodev);
+int reconfigure_single(struct super_block *s,
+ int flags, void *data)
+{
+ struct fs_context *fc;
+ int ret;
+
+ /* The caller really need to be passing fc down into mount_single(),
+ * then a chunk of this can be removed. [Bollocks -- AV]
+ * Better yet, reconfiguration shouldn't happen, but rather the second
+ * mount should be rejected if the parameters are not compatible.
+ */
+ fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK);
+ if (IS_ERR(fc))
+ return PTR_ERR(fc);
+
+ ret = parse_monolithic_mount_data(fc, data);
+ if (ret < 0)
+ goto out;
+
+ ret = reconfigure_super(fc);
+out:
+ put_fs_context(fc);
+ return ret;
+}
+
static int compare_single(struct super_block *s, void *p)
{
return 1;
@@ -1245,46 +1524,52 @@
return ERR_CAST(s);
if (!s->s_root) {
error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
- if (error) {
- deactivate_locked_super(s);
- return ERR_PTR(error);
- }
- s->s_flags |= SB_ACTIVE;
+ if (!error)
+ s->s_flags |= SB_ACTIVE;
} else {
- do_remount_sb(s, flags, data, 0);
+ error = reconfigure_single(s, flags, data);
+ }
+ if (unlikely(error)) {
+ deactivate_locked_super(s);
+ return ERR_PTR(error);
}
return dget(s->s_root);
}
EXPORT_SYMBOL(mount_single);
-struct dentry *
-mount_fs(struct file_system_type *type, int flags, const char *name, struct vfsmount *mnt, void *data)
+/**
+ * vfs_get_tree - Get the mountable root
+ * @fc: The superblock configuration context.
+ *
+ * The filesystem is invoked to get or create a superblock which can then later
+ * be used for mounting. The filesystem places a pointer to the root to be
+ * used for mounting in @fc->root.
+ */
+int vfs_get_tree(struct fs_context *fc)
{
- struct dentry *root;
struct super_block *sb;
- char *secdata = NULL;
- int error = -ENOMEM;
+ int error;
- if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
- secdata = alloc_secdata();
- if (!secdata)
- goto out;
+ if (fc->root)
+ return -EBUSY;
- error = security_sb_copy_data(data, secdata);
- if (error)
- goto out_free_secdata;
+ /* Get the mountable root in fc->root, with a ref on the root and a ref
+ * on the superblock.
+ */
+ error = fc->ops->get_tree(fc);
+ if (error < 0)
+ return error;
+
+ if (!fc->root) {
+ pr_err("Filesystem %s get_tree() didn't set fc->root\n",
+ fc->fs_type->name);
+ /* We don't know what the locking state of the superblock is -
+ * if there is a superblock.
+ */
+ BUG();
}
- if (type->mount2)
- root = type->mount2(mnt, type, flags, name, data);
- else
- root = type->mount(type, flags, name, data);
- if (IS_ERR(root)) {
- error = PTR_ERR(root);
- goto out_free_secdata;
- }
- sb = root->d_sb;
- BUG_ON(!sb);
+ sb = fc->root->d_sb;
WARN_ON(!sb->s_bdi);
/*
@@ -1296,9 +1581,11 @@
smp_wmb();
sb->s_flags |= SB_BORN;
- error = security_sb_kern_mount(sb, flags, secdata);
- if (error)
- goto out_sb;
+ error = security_sb_set_mnt_opts(sb, fc->security, 0, NULL);
+ if (unlikely(error)) {
+ fc_drop_locked(fc);
+ return error;
+ }
/*
* filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
@@ -1307,19 +1594,11 @@
* violate this rule.
*/
WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
- "negative value (%lld)\n", type->name, sb->s_maxbytes);
+ "negative value (%lld)\n", fc->fs_type->name, sb->s_maxbytes);
- up_write(&sb->s_umount);
- free_secdata(secdata);
- return root;
-out_sb:
- dput(root);
- deactivate_locked_super(sb);
-out_free_secdata:
- free_secdata(secdata);
-out:
- return ERR_PTR(error);
+ return 0;
}
+EXPORT_SYMBOL(vfs_get_tree);
/*
* Setup private BDI for given superblock. It gets automatically cleaned up
@@ -1331,11 +1610,9 @@
int err;
va_list args;
- bdi = bdi_alloc(GFP_KERNEL);
+ bdi = bdi_alloc(NUMA_NO_NODE);
if (!bdi)
return -ENOMEM;
-
- bdi->name = sb->s_type->name;
va_start(args, fmt);
err = bdi_register_va(bdi, fmt, args);
@@ -1363,30 +1640,6 @@
atomic_long_inc_return(&bdi_seq));
}
EXPORT_SYMBOL(super_setup_bdi);
-
-/*
- * This is an internal function, please use sb_end_{write,pagefault,intwrite}
- * instead.
- */
-void __sb_end_write(struct super_block *sb, int level)
-{
- percpu_up_read(sb->s_writers.rw_sem + level-1);
-}
-EXPORT_SYMBOL(__sb_end_write);
-
-/*
- * This is an internal function, please use sb_start_{write,pagefault,intwrite}
- * instead.
- */
-int __sb_start_write(struct super_block *sb, int level, bool wait)
-{
- if (!wait)
- return percpu_down_read_trylock(sb->s_writers.rw_sem + level-1);
-
- percpu_down_read(sb->s_writers.rw_sem + level-1);
- return 1;
-}
-EXPORT_SYMBOL(__sb_start_write);
/**
* sb_wait_write - wait until all writers to given file system finish
--
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