projects / thirdparty / man-pages.git / blame
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|---|---|---|
| fea681da MK |
1 | .\" Copyright (c) 1995 Michael Chastain (mec@shell.portal.com), 15 April 1995. |
| 2 | .\" | |
| e4a74ca8 | 3 | .\" SPDX-License-Identifier: GPL-2.0-or-later |
| fea681da MK |
4 | .\" |
| 5 | .\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com> | |
| c11b1abf | 6 | .\" Modified 2004-06-17 by Michael Kerrisk <mtk.manpages@gmail.com> |
| fea681da | 7 | .\" |
| 4c1c5274 | 8 | .TH bdflush 2 (date) "Linux man-pages (unreleased)" |
| fea681da MK |
9 | .SH NAME |
| 10 | bdflush \- start, flush, or tune buffer-dirty-flush daemon | |
| 11 | .SH SYNOPSIS | |
| 12 | .nf | |
| 332f4bb9 | 13 | .B #include <sys/kdaemon.h> |
| 8811e15a | 14 | .PP |
| a6fd076a AC |
15 | .BI "[[deprecated]] int bdflush(int " func ", long *" address ); |
| 16 | .BI "[[deprecated]] int bdflush(int " func ", long " data ); | |
| fea681da MK |
17 | .fi |
| 18 | .SH DESCRIPTION | |
| 966ba498 MK |
19 | .IR Note : |
| 20 | Since Linux 2.6, | |
| 4438c392 | 21 | .\" As noted in changes in the 2.5.12 source |
| 966ba498 MK |
22 | this system call is deprecated and does nothing. |
| 23 | It is likely to disappear altogether in a future kernel release. | |
| d6e37473 | 24 | Nowadays, the task performed by |
| 966ba498 MK |
25 | .BR bdflush () |
| 26 | is handled by the kernel | |
| 27 | .I pdflush | |
| 28 | thread. | |
| 8811e15a | 29 | .PP |
| e511ffb6 | 30 | .BR bdflush () |
| fea681da MK |
31 | starts, flushes, or tunes the buffer-dirty-flush daemon. |
| 32 | Only a privileged process (one with the | |
| 33 | .B CAP_SYS_ADMIN | |
| 34 | capability) may call | |
| e511ffb6 | 35 | .BR bdflush (). |
| fea681da MK |
36 | .PP |
| 37 | If | |
| 38 | .I func | |
| 39 | is negative or 0, and no daemon has been started, then | |
| e511ffb6 | 40 | .BR bdflush () |
| fea681da MK |
41 | enters the daemon code and never returns. |
| 42 | .PP | |
| 43 | If | |
| 44 | .I func | |
| 45 | is 1, | |
| 46 | some dirty buffers are written to disk. | |
| 47 | .PP | |
| 48 | If | |
| 49 | .I func | |
| 50 | is 2 or more and is even (low bit is 0), then | |
| 51 | .I address | |
| 52 | is the address of a long word, | |
| 53 | and the tuning parameter numbered | |
| 54 | .RI "(" "func" "\-2)/2" | |
| 55 | is returned to the caller in that address. | |
| 56 | .PP | |
| 57 | If | |
| 58 | .I func | |
| 59 | is 3 or more and is odd (low bit is 1), then | |
| 60 | .I data | |
| 61 | is a long word, | |
| 62 | and the kernel sets tuning parameter numbered | |
| 63 | .RI "(" "func" "\-3)/2" | |
| 64 | to that value. | |
| 65 | .PP | |
| e935e108 | 66 | The set of parameters, their values, and their valid ranges |
| 66a9882e | 67 | are defined in the Linux kernel source file |
| fea681da | 68 | .IR fs/buffer.c . |
| 47297adb | 69 | .SH RETURN VALUE |
| fea681da MK |
70 | If |
| 71 | .I func | |
| 72 | is negative or 0 and the daemon successfully starts, | |
| e511ffb6 | 73 | .BR bdflush () |
| fea681da MK |
74 | never returns. |
| 75 | Otherwise, the return value is 0 on success and \-1 on failure, with | |
| 76 | .I errno | |
| 77 | set to indicate the error. | |
| 78 | .SH ERRORS | |
| 79 | .TP | |
| 80 | .B EBUSY | |
| 81 | An attempt was made to enter the daemon code after | |
| 82 | another process has already entered. | |
| 83 | .TP | |
| 84 | .B EFAULT | |
| 85 | .I address | |
| 86 | points outside your accessible address space. | |
| 87 | .TP | |
| 88 | .B EINVAL | |
| 89 | An attempt was made to read or write an invalid parameter number, | |
| 90 | or to write an invalid value to a parameter. | |
| 91 | .TP | |
| 92 | .B EPERM | |
| 93 | Caller does not have the | |
| 94 | .B CAP_SYS_ADMIN | |
| 95 | capability. | |
| 74b807b4 | 96 | .SH VERSIONS |
| 7be3122f | 97 | Since version 2.23, glibc no longer supports this obsolete system call. |
| 3113c7f3 | 98 | .SH STANDARDS |
| 0bfa087b | 99 | .BR bdflush () |
| 8382f16d | 100 | is Linux-specific and should not be used in programs |
| fea681da | 101 | intended to be portable. |
| 47297adb | 102 | .SH SEE ALSO |
| a87041ac | 103 | .BR sync (1), |
| fea681da | 104 | .BR fsync (2), |
| a87041ac | 105 | .BR sync (2) |