ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
- int (*trim_fs) (struct super_block *, struct fstrim_range *);
locking rules:
All may block [not true, see below]
quota_read: no (see below)
quota_write: no (see below)
bdev_try_to_free_page: no (see below)
-trim_fs: no
->statfs() has s_umount (shared) when called by ustat(2) (native or
compat), but that's an accident of bad API; s_umount is used to pin