sb_permission(9)

🦋 sb_permission(9) — direct from the Kernel API Manual 🦋

okay bestie, we're doing a permission check page and it's lowkey iconic. This is straight outta the Kernel API Manual, and it's giving “separate the superblock vibes from the inode vibes.” Let's go. 💅

🎀 NAME 🎀

sb_permission — checks superblock-level permissions. That's the whole name vibe, fr fr.

✨ SYNOPSIS ✨

int sb_permission (struct super_block *sb , struct inode *inode , int
       mask );

💖 ARGUMENTS 💖

• sb — Superblock of inode to check permission on. It's the superblock bestie in question.
• inode — Inode to check permission on. The inode we're side-eyeing.
• mask — Right to check for (MAY_READ, MAY_WRITE, MAY_EXEC). These are the permission flavors, no cap.

🔥 DESCRIPTION 🔥

Okay so the actual job: this separates out the file-system wide checks from the inode-specific permission checks. That's it, that's the description, and honestly it ate. ✨

💅 NOTE 💅

Important note, bestie: lookup_inode_permission_may_exec does not call here. So if you add MAY_EXEC checks, adjust it. That's the whole warning — don't skip the adjustment, periodt. 💀

🌈 SEE ALSO 🌈

Kernel file ./fs/namei.c — and then the whole friend group, in order:

• check_acl(9)
• acl_permission_check(9)
• generic_permission(9)
• do_inode_permission(9)
• inode_permission(9)
• path_get(9)
• path_put(9)
• path_connected(9)
• try_to_unlazy(9)
• try_to_unlazy_next(9)
• complete_walk(9)
• may_follow_link(9)
• safe_hardlink_source(9)
• may_linkat(9)
• may_create_in_sticky(9)
• lookup_fast(9)
• start_dirop(9)
• end_dirop(9)
• kern_path_parent(9)
• vfs_path_parent_lookup(9)
• vfs_path_lookup(9)
• try_lookup_noperm(9)
• lookup_noperm(9)
• lookup_one(9)
• lookup_one_unlocked(9)
• lookup_one_positive_killable(9)
• lookup_one_positive_unlocked(9)
• lookup_noperm_unlocked(9)
• start_creating(9)
• start_removing(9)
• start_creating_killable(9)
• start_removing_killable(9)
• start_creating_noperm(9)
• start_removing_noperm(9)
• start_creating_dentry(9)
• start_removing_dentry(9)
• __start_renaming(9)
• start_renaming(9)
• start_renaming_dentry(9)
• start_renaming_two_dentries(9)
• vfs_prepare_mode(9)
• vfs_create(9)
• atomic_open(9)
• vfs_lookup_open(9)
• vfs_tmpfile(9)
• kernel_tmpfile_open(9)
• end_creating_path(9)
• dentry_create(9)
• vfs_mknod(9)
• vfs_mkdir(9)
• vfs_rmdir(9)
• vfs_unlink(9)
• vfs_symlink(9)
• vfs_link(9)
• vfs_rename(9)
• vfs_readlink(9)
• vfs_get_link(9)
• page_get_link(9)
• page_put_link(9)

okay bye bestie — this page comes from ./fs, dated October 2026, and it's still sb_permission(9); mwah 💋