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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-18 23:15:58 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-18 23:15:58 +0300
commite170eb27715fc9253ae031297d0638a3ef51b5da (patch)
tree3ae951bf6e1b759f91469a0a71ee0f59651bcc29 /fs
parentb30d87cf969e1711f1f621b6b61efb145ee6c6d9 (diff)
parent0f071004109d9c8de7023b9a64fa2ba3fa87cbed (diff)
downloadlinux-e170eb27715fc9253ae031297d0638a3ef51b5da.tar.xz
Merge branch 'work.mount-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs mount API infrastructure updates from Al Viro: "Infrastructure bits of mount API conversions. The rest is more of per-filesystem updates and that will happen in separate pull requests" * 'work.mount-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: mtd: Provide fs_context-aware mount_mtd() replacement vfs: Create fs_context-aware mount_bdev() replacement new helper: get_tree_keyed() vfs: set fs_context::user_ns for reconfigure
Diffstat (limited to 'fs')
-rw-r--r--fs/fs_context.c4
-rw-r--r--fs/nfsd/nfsctl.c3
-rw-r--r--fs/proc/root.c3
-rw-r--r--fs/super.c104
4 files changed, 107 insertions, 7 deletions
diff --git a/fs/fs_context.c b/fs/fs_context.c
index 103643c68e3f..87c2c9687d90 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -279,10 +279,8 @@ static struct fs_context *alloc_fs_context(struct file_system_type *fs_type,
fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
break;
case FS_CONTEXT_FOR_RECONFIGURE:
- /* We don't pin any namespaces as the superblock's
- * subscriptions cannot be changed at this point.
- */
atomic_inc(&reference->d_sb->s_active);
+ fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
fc->root = dget(reference);
break;
}
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 3cf4f6aa48d6..2c215171c0eb 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1385,8 +1385,7 @@ static int nfsd_fill_super(struct super_block *sb, struct fs_context *fc)
static int nfsd_fs_get_tree(struct fs_context *fc)
{
- fc->s_fs_info = get_net(fc->net_ns);
- return vfs_get_super(fc, vfs_get_keyed_super, nfsd_fill_super);
+ return get_tree_keyed(fc, nfsd_fill_super, get_net(fc->net_ns));
}
static void nfsd_fs_free_fc(struct fs_context *fc)
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 33f72d1b92cc..0b7c8dffc9ae 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -157,8 +157,7 @@ static int proc_get_tree(struct fs_context *fc)
{
struct proc_fs_context *ctx = fc->fs_private;
- fc->s_fs_info = ctx->pid_ns;
- return vfs_get_super(fc, vfs_get_keyed_super, proc_fill_super);
+ return get_tree_keyed(fc, proc_fill_super, ctx->pid_ns);
}
static void proc_fs_context_free(struct fs_context *fc)
diff --git a/fs/super.c b/fs/super.c
index 5960578a4076..da223b4cfbca 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1211,7 +1211,18 @@ int get_tree_single(struct fs_context *fc,
}
EXPORT_SYMBOL(get_tree_single);
+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;
@@ -1221,6 +1232,99 @@ static int set_bdev_super(struct super_block *s, void *data)
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);
+ 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))
+ 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)
{
return (void *)s->s_bdev == data;