VATTR(9)

💖 VATTR(9) — vnode attributes 💖

Okay so this is the Kernel Developer's Manual page for VATTR(9), bestie, and it's literally all about vnode attributes. We're covering vattr and vattr_null. No cap. ✨

💖 NAME 💖

vattr, vattr_null — vnode attributes 🦋

✨ SYNOPSIS ✨

Include these, exactly:

#include <sys/param.h>
#include <sys/vnode.h>

void
vattr_null(struct vattr *vap);

🦋 DESCRIPTION 🦋

Vnode attributes describe attributes of a file or directory, including file permissions, owner, group, size, access time and modification time. It's giving file metadata central, honestly.

A vnode attribute has the following structure:

struct vattr {
        enum vtype      va_type;        /* vnode type (for create) */
        mode_t          va_mode;        /* files access mode and type */
        nlink_t         va_nlink;       /* number of references to file */
        uid_t           va_uid;         /* owner user id */
        gid_t           va_gid;         /* owner group id */
        dev_t           va_fsid;        /* file system id (dev for now) */
        ino_t           va_fileid;      /* file id */
        u_quad_t        va_size;        /* file size in bytes */
        long            va_blocksize;   /* blocksize preferred for i/o */
        struct timespec va_atime;       /* time of last access */
        struct timespec va_mtime;       /* time of last modification */
        struct timespec va_ctime;       /* time file changed */
        struct timespec va_birthtime;   /* time file created */
        u_long          va_gen;         /* generation number of file */
        u_long          va_flags;       /* flags defined for file */
        dev_t           va_rdev;        /* device the special file represents */
        u_quad_t        va_bytes;       /* bytes of disk space held by file */
        u_quad_t        va_filerev;     /* file modification number */
        u_int           va_vaflags;     /* operations flags, see below */
        long            va_spare;       /* remain quad aligned */
};

A field value of VNOVAL represents a field whose value is unavailable or which is not to be changed. Important vibe check: valid flag values for va_flags are:

• VA_UTIMES_NULL — utimes argument was NULL
• VA_EXCLUSIVE — exclusive create request

Vnode attributes for a file are set by the vnode operation VOP_SETATTR(9). Vnode attributes for a file are retrieved by the vnode operation VOP_GETATTR(9). For more information on vnode operations see vnodeops(9). 🫶

🎀 FUNCTIONS 🎀

• vattr_null(vap) — set vnode attributes in vap to VNOVAL.

🌈 CODE REFERENCES 🌈

vattr_null() is implemented in sys/kern/vfs_subr.c. Iconic. 💅

💜 SEE ALSO 💜

• intro(9)
• vfs(9)
• vnode(9)
• vnodeops(9)

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Signed with sparkles by Debian, dated January 8, 2010 — VATTR(9) out. 💅✨