Messages in this thread | | | From | Daeho Jeong <> | Date | Wed, 1 Jul 2020 16:04:52 +0900 | Subject | Re: [f2fs-dev] [PATCH] f2fs: add symbolic link to kobject in sysfs |
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Actually, I want to keep the mount number remaining to the same number, even if it's re-mounted. Or we need to keep track of the number being increased whenever it's remounted. :(
2020년 7월 1일 (수) 오후 3:36, Chao Yu <yuchao0@huawei.com>님이 작성: > > Hi Daeho, > > On 2020/6/30 8:56, Daeho Jeong wrote: > > From: Daeho Jeong <daehojeong@google.com> > > > > Added a symbolic link to directory of sysfs. It will > > create a symbolic link such as "mount_0" and "mount_1" to > > each f2fs mount in the order of mounting filesystem. It will > > provide easy access to sysfs node even if not knowing the > > specific device node name like sda19 and dm-3. > > Just out of curiosity, if we mount/umount as below: > > mount /dev/zram0 /mnt/f2fs0 > mount /dev/zram1 /mnt/f2fs1 > umount /mnt/f2fs0 > mount /dev/zram0 /mnt/f2fs0 > > Shouldn't sysfs structure be: > mount_2 -> zram0 > mount_1 -> zram1 > zram0 > zram1 > > Then we can know zram0 is mounted after zram1? > > However the result shows: > mount_0 -> zram0 > mount_1 -> zram1 > zram0 > zram1 > > Thanks, > > > > > Signed-off-by: Daeho Jeong <daehojeong@google.com> > > --- > > fs/f2fs/f2fs.h | 4 ++++ > > fs/f2fs/sysfs.c | 31 +++++++++++++++++++++++++++---- > > 2 files changed, 31 insertions(+), 4 deletions(-) > > > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > > index 4b28fd42fdbc..7d6c5f8ce16b 100644 > > --- a/fs/f2fs/f2fs.h > > +++ b/fs/f2fs/f2fs.h > > @@ -1419,6 +1419,8 @@ struct decompress_io_ctx { > > #define MAX_COMPRESS_LOG_SIZE 8 > > #define MAX_COMPRESS_WINDOW_SIZE ((PAGE_SIZE) << MAX_COMPRESS_LOG_SIZE) > > > > +#define MOUNT_NAME_SIZE 20 > > + > > struct f2fs_sb_info { > > struct super_block *sb; /* pointer to VFS super block */ > > struct proc_dir_entry *s_proc; /* proc entry */ > > @@ -1599,6 +1601,8 @@ struct f2fs_sb_info { > > /* For sysfs suppport */ > > struct kobject s_kobj; > > struct completion s_kobj_unregister; > > + int s_mount_id; > > + char s_mount_name[MOUNT_NAME_SIZE]; > > > > /* For shrinker support */ > > struct list_head s_list; > > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c > > index ab40e1f89f23..64bbe0b3b830 100644 > > --- a/fs/f2fs/sysfs.c > > +++ b/fs/f2fs/sysfs.c > > @@ -18,6 +18,7 @@ > > #include <trace/events/f2fs.h> > > > > static struct proc_dir_entry *f2fs_proc_root; > > +static struct ida f2fs_mount_ida; > > > > /* Sysfs support for f2fs */ > > enum { > > @@ -906,6 +907,9 @@ int __init f2fs_init_sysfs(void) > > } else { > > f2fs_proc_root = proc_mkdir("fs/f2fs", NULL); > > } > > + > > + ida_init(&f2fs_mount_ida); > > + > > return ret; > > } > > > > @@ -915,6 +919,7 @@ void f2fs_exit_sysfs(void) > > kset_unregister(&f2fs_kset); > > remove_proc_entry("fs/f2fs", NULL); > > f2fs_proc_root = NULL; > > + ida_destroy(&f2fs_mount_ida); > > } > > > > int f2fs_register_sysfs(struct f2fs_sb_info *sbi) > > @@ -926,12 +931,22 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi) > > init_completion(&sbi->s_kobj_unregister); > > err = kobject_init_and_add(&sbi->s_kobj, &f2fs_sb_ktype, NULL, > > "%s", sb->s_id); > > - if (err) { > > - kobject_put(&sbi->s_kobj); > > - wait_for_completion(&sbi->s_kobj_unregister); > > - return err; > > + if (err) > > + goto err1; > > + > > + sbi->s_mount_id = ida_simple_get(&f2fs_mount_ida, 0, 0, GFP_KERNEL); > > + if (sbi->s_mount_id < 0) { > > + err = sbi->s_mount_id; > > + goto err1; > > } > > > > + snprintf(sbi->s_mount_name, MOUNT_NAME_SIZE, "mount_%d", > > + sbi->s_mount_id); > > + err = sysfs_create_link(&f2fs_kset.kobj, &sbi->s_kobj, > > + sbi->s_mount_name); > > + if (err) > > + goto err2; > > + > > if (f2fs_proc_root) > > sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root); > > > > @@ -946,6 +961,12 @@ int f2fs_register_sysfs(struct f2fs_sb_info *sbi) > > victim_bits_seq_show, sb); > > } > > return 0; > > +err2: > > + ida_simple_remove(&f2fs_mount_ida, sbi->s_mount_id); > > +err1: > > + kobject_put(&sbi->s_kobj); > > + wait_for_completion(&sbi->s_kobj_unregister); > > + return err; > > } > > > > void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi) > > @@ -957,6 +978,8 @@ void f2fs_unregister_sysfs(struct f2fs_sb_info *sbi) > > remove_proc_entry("victim_bits", sbi->s_proc); > > remove_proc_entry(sbi->sb->s_id, f2fs_proc_root); > > } > > + sysfs_remove_link(&f2fs_kset.kobj, sbi->s_mount_name); > > + ida_simple_remove(&f2fs_mount_ida, sbi->s_mount_id); > > kobject_del(&sbi->s_kobj); > > kobject_put(&sbi->s_kobj); > > } > >
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