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fs: retire sget()

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sget() and sget_fc() have lived side by side as near-duplicate
find-or-create-and-publish helpers for the legacy and fs_context mount
APIs. The three remaining in-tree callers (CIFS plus the ext4 extents
and mballoc KUnit tests) have all been moved to sget_fc(). Nothing
calls sget() anymore.

Delete sget() from fs/super.c and the prototype in <linux/fs.h>.
Update the two comments that referred to "sget()" or "sget{_fc}()" to
just say "sget_fc()".

This removes ~60 lines of code that only existed to be kept in
lockstep with sget_fc() on every superblock publish-path change.

Link: https://patch.msgid.link/20260529-work-sget-v2-4-57bbe08604e4@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2026-05-29 10:43:43 +02:00
parent b50d895dfd
commit 12863b36bf
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GPG Key ID: 91C61BC06578DCA2
3 changed files with 6 additions and 71 deletions
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2
fs/btrfs/super.c
View File

@ -2052,7 +2052,7 @@ static int btrfs_get_tree_subvol(struct fs_context *fc)
* then open_ctree will properly initialize the file system specific
* settings later. btrfs_init_fs_info initializes the static elements
* of the fs_info (locks and such) to make cleanup easier if we find a
* superblock with our given fs_devices later on at sget() time.
* superblock with our given fs_devices later on at sget_fc() time.
*/
fs_info = kvzalloc_obj(struct btrfs_fs_info);
if (!fs_info)

71
fs/super.c
View File

@ -328,7 +328,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
init_rwsem(&s->s_umount);
lockdep_set_class(&s->s_umount, &type->s_umount_key);
/*
* sget() can have s_umount recursion.
* sget_fc() can have s_umount recursion.
*
* When it cannot find a suitable sb, it allocates a new
* one (this one), and tries again to find a suitable old
@ -439,7 +439,7 @@ static void kill_super_notify(struct super_block *sb)
/*
* Remove it from @fs_supers so it isn't found by new
* sget{_fc}() walkers anymore. Any concurrent mounter still
* sget_fc() walkers anymore. Any concurrent mounter still
* managing to grab a temporary reference is guaranteed to
* already see SB_DYING and will wait until we notify them about
* SB_DEAD.
@ -517,7 +517,7 @@ EXPORT_SYMBOL(deactivate_super);
* @sb: superblock to acquire
*
* Acquire a temporary reference on a superblock and try to trade it for
* an active reference. This is used in sget{_fc}() to wait for a
* an active reference. This is used in sget_fc() to wait for a
* superblock to either become SB_BORN or for it to pass through
* sb->kill() and be marked as SB_DEAD.
*
@ -673,11 +673,11 @@ void generic_shutdown_super(struct super_block *sb)
/*
* Broadcast to everyone that grabbed a temporary reference to this
* superblock before we removed it from @fs_supers that the superblock
* is dying. Every walker of @fs_supers outside of sget{_fc}() will now
* is dying. Every walker of @fs_supers outside of sget_fc() will now
* discard this superblock and treat it as dead.
*
* We leave the superblock on @fs_supers so it can be found by
* sget{_fc}() until we passed sb->kill_sb().
* sget_fc() until we passed sb->kill_sb().
*/
super_wake(sb, SB_DYING);
super_unlock_excl(sb);
@ -808,67 +808,6 @@ struct super_block *sget_fc(struct fs_context *fc,
}
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,
void *data)
{
struct user_namespace *user_ns = current_user_ns();
struct super_block *s = NULL;
struct super_block *old;
int err;
retry:
spin_lock(&sb_lock);
if (test) {
hlist_for_each_entry(old, &type->fs_supers, s_instances) {
if (!test(old, data))
continue;
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;
}
}
if (!s) {
spin_unlock(&sb_lock);
s = alloc_super(type, flags, user_ns);
if (!s)
return ERR_PTR(-ENOMEM);
goto retry;
}
err = set(s, data);
if (err) {
spin_unlock(&sb_lock);
destroy_unused_super(s);
return ERR_PTR(err);
}
s->s_type = type;
strscpy(s->s_id, type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(type);
shrinker_register(s->s_shrink);
return s;
}
EXPORT_SYMBOL(sget);
void drop_super(struct super_block *sb)
{
super_unlock_shared(sb);

4
include/linux/fs.h
View File

@ -2327,10 +2327,6 @@ void free_anon_bdev(dev_t);
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 *sget(struct file_system_type *type,
int (*test)(struct super_block *,void *),
int (*set)(struct super_block *,void *),
int flags, void *data);
struct super_block *sget_dev(struct fs_context *fc, dev_t dev);
/* Alas, no aliases. Too much hassle with bringing module.h everywhere */