Messages in this thread Patch in this message | | | From | Daeho Jeong <> | Subject | [PATCH v3] f2fs: add symbolic link to kobject in sysfs | Date | Fri, 3 Jul 2020 15:54:20 +0900 |
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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. But once one mount point was umounted, that sequential number @x in "mount_@x" could be reused by later newly mounted point. It will provide easy access to sysfs node even if not knowing the specific device node name like sda19 and dm-3.
Signed-off-by: Daeho Jeong <daehojeong@google.com> --- Documentation/filesystems/f2fs.rst | 13 ++++++++++++- fs/f2fs/f2fs.h | 4 ++++ fs/f2fs/sysfs.c | 31 ++++++++++++++++++++++++++---- 3 files changed, 43 insertions(+), 5 deletions(-)
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index 535021c46260..916956d433b2 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -279,7 +279,18 @@ Sysfs Entries Information about mounted f2fs file systems can be found in /sys/fs/f2fs. Each mounted filesystem will have a directory in -/sys/fs/f2fs based on its device name (i.e., /sys/fs/f2fs/sda). +/sys/fs/f2fs based on its device name (i.e., /sys/fs/f2fs/sda), +or mount_#x (#x is the number representing the order of mounting). +But once one mount point was umounted, that sequential number @x +in "mount_@x" could be reused by later newly mounted point. + +Here is an example of this. + +mount dev0 mount0 (mount_0 -> dev0) +mount dev1 mount1 (mount_1 -> dev1) +umount mount0 +mount dev2 (mount_0 -> dev2) + The files in each per-device directory are shown in table below. Files in /sys/fs/f2fs/<devname> 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 2a140657fc4d..703d9f460d03 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 { @@ -908,6 +909,9 @@ int __init f2fs_init_sysfs(void) } else { f2fs_proc_root = proc_mkdir("fs/f2fs", NULL); } + + ida_init(&f2fs_mount_ida); + return ret; } @@ -917,6 +921,7 @@ 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) @@ -928,12 +933,22 @@ 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); @@ -948,6 +963,12 @@ 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) @@ -959,6 +980,8 @@ 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); } -- 2.27.0.383.g050319c2ae-goog
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