[PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed

Christoph Hellwig
2020-11-28T22:12:03Z

Just open code the wait in the only caller of both functions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
fs/internal.h | 2 ++
fs/quota/quota.c | 31 +++++++++++++++++++++-------
fs/super.c | 51 ++--------------------------------------------
include/linux/fs.h | 4 +---
4 files changed, 29 insertions(+), 59 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index a7cd0f64faa4ab..47be21dfeebef5 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -114,7 +114,9 @@ extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
*/
extern int reconfigure_super(struct fs_context *);
extern bool trylock_super(struct super_block *sb);
+struct super_block *__get_super(struct block_device *bdev, bool excl);
extern struct super_block *user_get_super(dev_t);
+void put_super(struct super_block *sb);
extern bool mount_capable(struct fs_context *);

/*
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 9af95c7a0bbe3c..f3d32b0d9008f2 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -20,6 +20,7 @@
#include <linux/writeback.h>
#include <linux/nospec.h>
#include "compat.h"
+#include "../internal.h"

static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
qid_t id)
@@ -868,6 +869,7 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
struct block_device *bdev;
struct super_block *sb;
struct filename *tmp = getname(special);
+ bool excl = false, thawed = false;

if (IS_ERR(tmp))
return ERR_CAST(tmp);
@@ -875,17 +877,32 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
putname(tmp);
if (IS_ERR(bdev))
return ERR_CAST(bdev);
- if (quotactl_cmd_onoff(cmd))
- sb = get_super_exclusive_thawed(bdev);
- else if (quotactl_cmd_write(cmd))
- sb = get_super_thawed(bdev);
- else
- sb = get_super(bdev);
+
+ if (quotactl_cmd_onoff(cmd)) {
+ excl = true;
+ thawed = true;
+ } else if (quotactl_cmd_write(cmd)) {
+ thawed = true;
+ }
+
+retry:
+ sb = __get_super(bdev, excl);
+ if (thawed && sb && sb->s_writers.frozen != SB_UNFROZEN) {
+ if (excl)
+ up_write(&sb->s_umount);
+ else
+ up_read(&sb->s_umount);
+ wait_event(sb->s_writers.wait_unfrozen,
+ sb->s_writers.frozen == SB_UNFROZEN);
+ put_super(sb);
+ goto retry;
+ }
+
bdput(bdev);
if (!sb)
return ERR_PTR(-ENODEV);
-
return sb;
+
#else
return ERR_PTR(-ENODEV);
#endif
diff --git a/fs/super.c b/fs/super.c
index 98bb0629ee108e..343e5c1e538d2a 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -307,7 +307,7 @@ static void __put_super(struct super_block *s)
* Drops a temporary reference, frees superblock if there's no
* references left.
*/
-static void put_super(struct super_block *sb)
+void put_super(struct super_block *sb)
{
spin_lock(&sb_lock);
__put_super(sb);
@@ -740,7 +740,7 @@ void iterate_supers_type(struct file_system_type *type,

EXPORT_SYMBOL(iterate_supers_type);

-static struct super_block *__get_super(struct block_device *bdev, bool excl)
+struct super_block *__get_super(struct block_device *bdev, bool excl)
{
struct super_block *sb;

@@ -789,53 +789,6 @@ struct super_block *get_super(struct block_device *bdev)
}
EXPORT_SYMBOL(get_super);

-static struct super_block *__get_super_thawed(struct block_device *bdev,
- bool excl)
-{
- while (1) {
- struct super_block *s = __get_super(bdev, excl);
- if (!s || s->s_writers.frozen == SB_UNFROZEN)
- return s;
- if (!excl)
- up_read(&s->s_umount);
- else
- up_write(&s->s_umount);
- wait_event(s->s_writers.wait_unfrozen,
- s->s_writers.frozen == SB_UNFROZEN);
- put_super(s);
- }
-}
-
-/**
- * get_super_thawed - get thawed superblock of a device
- * @bdev: device to get the superblock for
- *
- * Scans the superblock list and finds the superblock of the file system
- * mounted on the device. The superblock is returned once it is thawed
- * (or immediately if it was not frozen). %NULL is returned if no match
- * is found.
- */
-struct super_block *get_super_thawed(struct block_device *bdev)
-{
- return __get_super_thawed(bdev, false);
-}
-EXPORT_SYMBOL(get_super_thawed);
-
-/**
- * get_super_exclusive_thawed - get thawed superblock of a device
- * @bdev: device to get the superblock for
- *
- * Scans the superblock list and finds the superblock of the file system
- * mounted on the device. The superblock is returned once it is thawed
- * (or immediately if it was not frozen) and s_umount semaphore is held
- * in exclusive mode. %NULL is returned if no match is found.
- */
-struct super_block *get_super_exclusive_thawed(struct block_device *bdev)
-{
- return __get_super_thawed(bdev, true);
-}
-EXPORT_SYMBOL(get_super_exclusive_thawed);
-
/**
* get_active_super - get an active reference to the superblock of a device
* @bdev: device to get the superblock for
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8667d0cdc71e76..a61df0dd4f1989 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1409,7 +1409,7 @@ enum {

struct sb_writers {
int frozen; /* Is sb frozen? */
- wait_queue_head_t wait_unfrozen; /* for get_super_thawed() */
+ wait_queue_head_t wait_unfrozen; /* wait for thaw */
struct percpu_rw_semaphore rw_sem[SB_FREEZE_LEVELS];
};

@@ -3132,8 +3132,6 @@ extern struct file_system_type *get_filesystem(struct file_system_type *fs);
extern void put_filesystem(struct file_system_type *fs);
extern struct file_system_type *get_fs_type(const char *name);
extern struct super_block *get_super(struct block_device *);
-extern struct super_block *get_super_thawed(struct block_device *);
-extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
extern struct super_block *get_active_super(struct block_device *bdev);
extern void drop_super(struct super_block *sb);
extern void drop_super_exclusive(struct super_block *sb);
--
2.29.2