7b7b1ace2d
The way we currently deal with quota and process accounting that might keep vfsmount busy at umount time is inherently broken; we try to turn them off just in case (not quite correctly, at that) and a) pray umount doesn't fail (otherwise they'll stay turned off) b) pray nobody doesn anything funny just as we turn quota off Moreover, LSM provides hooks for doing the same sort of broken logics. The proper way to deal with that is to introduce the second kind of reference to vfsmount. Semantics: - when the last normal reference is dropped, all special ones are converted to normal ones and if there had been any, cleanup is done. - normal reference can be cloned into a special one - special reference can be converted to normal one; that's a no-op if we'd already passed the point of no return (i.e. mntput() had converted special references to normal and started cleanup). The way it works: e.g. starting process accounting converts the vfsmount reference pinned by the opened file into special one and turns it back to normal when it gets shut down; acct_auto_close() is done when no normal references are left. That way it does *not* obstruct umount(2) and it silently gets turned off when the last normal reference to vfsmount is gone. Which is exactly what we want... The same should be done by LSM module that holds some internal references to vfsmount and wants to shut them down on umount - it should make them special and security_sb_umount_close() will be called exactly when the last normal reference to vfsmount is gone. quota handling is even simpler - we don't use normal file IO anymore, so there's no need to hold vfsmounts at all. DQUOT_OFF() is done from deactivate_super(), where it really belongs. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
204 lines
5.7 KiB
C
204 lines
5.7 KiB
C
/*
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* BSD Process Accounting for Linux - Definitions
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*
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* Author: Marco van Wieringen (mvw@planets.elm.net)
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*
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* This header file contains the definitions needed to implement
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* BSD-style process accounting. The kernel accounting code and all
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* user-level programs that try to do something useful with the
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* process accounting log must include this file.
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*
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* Copyright (C) 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
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*
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*/
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#ifndef _LINUX_ACCT_H
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#define _LINUX_ACCT_H
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#include <linux/types.h>
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#include <asm/param.h>
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#include <asm/byteorder.h>
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/*
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* comp_t is a 16-bit "floating" point number with a 3-bit base 8
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* exponent and a 13-bit fraction.
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* comp2_t is 24-bit with 5-bit base 2 exponent and 20 bit fraction
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* (leading 1 not stored).
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* See linux/kernel/acct.c for the specific encoding systems used.
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*/
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typedef __u16 comp_t;
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typedef __u32 comp2_t;
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/*
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* accounting file record
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*
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* This structure contains all of the information written out to the
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* process accounting file whenever a process exits.
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*/
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#define ACCT_COMM 16
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struct acct
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{
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char ac_flag; /* Flags */
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char ac_version; /* Always set to ACCT_VERSION */
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/* for binary compatibility back until 2.0 */
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__u16 ac_uid16; /* LSB of Real User ID */
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__u16 ac_gid16; /* LSB of Real Group ID */
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__u16 ac_tty; /* Control Terminal */
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__u32 ac_btime; /* Process Creation Time */
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comp_t ac_utime; /* User Time */
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comp_t ac_stime; /* System Time */
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comp_t ac_etime; /* Elapsed Time */
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comp_t ac_mem; /* Average Memory Usage */
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comp_t ac_io; /* Chars Transferred */
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comp_t ac_rw; /* Blocks Read or Written */
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comp_t ac_minflt; /* Minor Pagefaults */
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comp_t ac_majflt; /* Major Pagefaults */
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comp_t ac_swaps; /* Number of Swaps */
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/* m68k had no padding here. */
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#if !defined(CONFIG_M68K) || !defined(__KERNEL__)
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__u16 ac_ahz; /* AHZ */
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#endif
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__u32 ac_exitcode; /* Exitcode */
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char ac_comm[ACCT_COMM + 1]; /* Command Name */
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__u8 ac_etime_hi; /* Elapsed Time MSB */
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__u16 ac_etime_lo; /* Elapsed Time LSB */
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__u32 ac_uid; /* Real User ID */
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__u32 ac_gid; /* Real Group ID */
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};
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struct acct_v3
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{
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char ac_flag; /* Flags */
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char ac_version; /* Always set to ACCT_VERSION */
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__u16 ac_tty; /* Control Terminal */
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__u32 ac_exitcode; /* Exitcode */
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__u32 ac_uid; /* Real User ID */
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__u32 ac_gid; /* Real Group ID */
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__u32 ac_pid; /* Process ID */
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__u32 ac_ppid; /* Parent Process ID */
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__u32 ac_btime; /* Process Creation Time */
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#ifdef __KERNEL__
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__u32 ac_etime; /* Elapsed Time */
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#else
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float ac_etime; /* Elapsed Time */
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#endif
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comp_t ac_utime; /* User Time */
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comp_t ac_stime; /* System Time */
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comp_t ac_mem; /* Average Memory Usage */
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comp_t ac_io; /* Chars Transferred */
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comp_t ac_rw; /* Blocks Read or Written */
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comp_t ac_minflt; /* Minor Pagefaults */
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comp_t ac_majflt; /* Major Pagefaults */
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comp_t ac_swaps; /* Number of Swaps */
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char ac_comm[ACCT_COMM]; /* Command Name */
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};
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/*
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* accounting flags
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*/
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/* bit set when the process ... */
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#define AFORK 0x01 /* ... executed fork, but did not exec */
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#define ASU 0x02 /* ... used super-user privileges */
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#define ACOMPAT 0x04 /* ... used compatibility mode (VAX only not used) */
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#define ACORE 0x08 /* ... dumped core */
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#define AXSIG 0x10 /* ... was killed by a signal */
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#ifdef __BIG_ENDIAN
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#define ACCT_BYTEORDER 0x80 /* accounting file is big endian */
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#else
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#define ACCT_BYTEORDER 0x00 /* accounting file is little endian */
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#endif
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#ifdef __KERNEL__
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#include <linux/config.h>
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#ifdef CONFIG_BSD_PROCESS_ACCT
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struct vfsmount;
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struct super_block;
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extern void acct_auto_close_mnt(struct vfsmount *m);
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extern void acct_auto_close(struct super_block *sb);
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extern void acct_process(long exitcode);
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extern void acct_update_integrals(struct task_struct *tsk);
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extern void acct_clear_integrals(struct task_struct *tsk);
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#else
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#define acct_auto_close_mnt(x) do { } while (0)
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#define acct_auto_close(x) do { } while (0)
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#define acct_process(x) do { } while (0)
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#define acct_update_integrals(x) do { } while (0)
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#define acct_clear_integrals(task) do { } while (0)
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#endif
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/*
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* ACCT_VERSION numbers as yet defined:
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* 0: old format (until 2.6.7) with 16 bit uid/gid
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* 1: extended variant (binary compatible on M68K)
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* 2: extended variant (binary compatible on everything except M68K)
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* 3: new binary incompatible format (64 bytes)
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* 4: new binary incompatible format (128 bytes)
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* 5: new binary incompatible format (128 bytes, second half)
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*
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*/
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#ifdef CONFIG_BSD_PROCESS_ACCT_V3
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#define ACCT_VERSION 3
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#define AHZ 100
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typedef struct acct_v3 acct_t;
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#else
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#ifdef CONFIG_M68K
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#define ACCT_VERSION 1
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#else
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#define ACCT_VERSION 2
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#endif
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#define AHZ (USER_HZ)
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typedef struct acct acct_t;
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#endif
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#else
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#define ACCT_VERSION 2
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#define AHZ (HZ)
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#endif /* __KERNEL */
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#ifdef __KERNEL__
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/*
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* Yet another set of HZ to *HZ helper functions.
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* See <linux/jiffies.h> for the original.
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*/
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static inline u32 jiffies_to_AHZ(unsigned long x)
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{
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#if (TICK_NSEC % (NSEC_PER_SEC / AHZ)) == 0
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return x / (HZ / AHZ);
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#else
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u64 tmp = (u64)x * TICK_NSEC;
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do_div(tmp, (NSEC_PER_SEC / AHZ));
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return (long)tmp;
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#endif
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}
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static inline u64 nsec_to_AHZ(u64 x)
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{
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#if (NSEC_PER_SEC % AHZ) == 0
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do_div(x, (NSEC_PER_SEC / AHZ));
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#elif (AHZ % 512) == 0
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x *= AHZ/512;
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do_div(x, (NSEC_PER_SEC / 512));
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#else
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/*
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* max relative error 5.7e-8 (1.8s per year) for AHZ <= 1024,
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* overflow after 64.99 years.
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* exact for AHZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
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*/
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x *= 9;
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do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (AHZ/2))
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/ AHZ));
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#endif
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return x;
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}
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#endif /* __KERNEL */
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#endif /* _LINUX_ACCT_H */
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