Revision 35991652baa12ff3d0e420c0d0cb2ad9f7076e5b authored by Mikulas Patocka on 02 June 2012, 23:29:58 UTC, committed by Alasdair G Kergon on 02 June 2012, 23:29:58 UTC
After the failure of a group of paths, any alternative paths that need initialising do not become available until further I/O is sent to the device. Until this has happened, ioctls return -EAGAIN. With this patch, new paths are made available in response to an ioctl too. The processing of the ioctl gets delayed until this has happened. Instead of returning an error, we submit a work item to kmultipathd (that will potentially activate the new path) and retry in ten milliseconds. Note that the patch doesn't retry an ioctl if the ioctl itself fails due to a path failure. Such retries should be handled intelligently by the code that generated the ioctl in the first place, noting that some SCSI commands should not be retried because they are not idempotent (XOR write commands). For commands that could be retried, there is a danger that if the device rejected the SCSI command, the path could be errorneously marked as failed, and the request would be retried on another path which might fail too. It can be determined if the failure happens on the device or on the SCSI controller, but there is no guarantee that all SCSI drivers set these flags correctly. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 parent f220fd4
compr_zlib.c
/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#if !defined(__KERNEL__) && !defined(__ECOS)
#error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
#endif
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/zlib.h>
#include <linux/zutil.h>
#include "nodelist.h"
#include "compr.h"
/* Plan: call deflate() with avail_in == *sourcelen,
avail_out = *dstlen - 12 and flush == Z_FINISH.
If it doesn't manage to finish, call it again with
avail_in == 0 and avail_out set to the remaining 12
bytes for it to clean up.
Q: Is 12 bytes sufficient?
*/
#define STREAM_END_SPACE 12
static DEFINE_MUTEX(deflate_mutex);
static DEFINE_MUTEX(inflate_mutex);
static z_stream inf_strm, def_strm;
#ifdef __KERNEL__ /* Linux-only */
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/mutex.h>
static int __init alloc_workspaces(void)
{
def_strm.workspace = vmalloc(zlib_deflate_workspacesize(MAX_WBITS,
MAX_MEM_LEVEL));
if (!def_strm.workspace)
return -ENOMEM;
jffs2_dbg(1, "Allocated %d bytes for deflate workspace\n",
zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL));
inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
if (!inf_strm.workspace) {
vfree(def_strm.workspace);
return -ENOMEM;
}
jffs2_dbg(1, "Allocated %d bytes for inflate workspace\n",
zlib_inflate_workspacesize());
return 0;
}
static void free_workspaces(void)
{
vfree(def_strm.workspace);
vfree(inf_strm.workspace);
}
#else
#define alloc_workspaces() (0)
#define free_workspaces() do { } while(0)
#endif /* __KERNEL__ */
static int jffs2_zlib_compress(unsigned char *data_in,
unsigned char *cpage_out,
uint32_t *sourcelen, uint32_t *dstlen)
{
int ret;
if (*dstlen <= STREAM_END_SPACE)
return -1;
mutex_lock(&deflate_mutex);
if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
pr_warn("deflateInit failed\n");
mutex_unlock(&deflate_mutex);
return -1;
}
def_strm.next_in = data_in;
def_strm.total_in = 0;
def_strm.next_out = cpage_out;
def_strm.total_out = 0;
while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
jffs2_dbg(1, "calling deflate with avail_in %d, avail_out %d\n",
def_strm.avail_in, def_strm.avail_out);
ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
jffs2_dbg(1, "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
def_strm.avail_in, def_strm.avail_out,
def_strm.total_in, def_strm.total_out);
if (ret != Z_OK) {
jffs2_dbg(1, "deflate in loop returned %d\n", ret);
zlib_deflateEnd(&def_strm);
mutex_unlock(&deflate_mutex);
return -1;
}
}
def_strm.avail_out += STREAM_END_SPACE;
def_strm.avail_in = 0;
ret = zlib_deflate(&def_strm, Z_FINISH);
zlib_deflateEnd(&def_strm);
if (ret != Z_STREAM_END) {
jffs2_dbg(1, "final deflate returned %d\n", ret);
ret = -1;
goto out;
}
if (def_strm.total_out >= def_strm.total_in) {
jffs2_dbg(1, "zlib compressed %ld bytes into %ld; failing\n",
def_strm.total_in, def_strm.total_out);
ret = -1;
goto out;
}
jffs2_dbg(1, "zlib compressed %ld bytes into %ld\n",
def_strm.total_in, def_strm.total_out);
*dstlen = def_strm.total_out;
*sourcelen = def_strm.total_in;
ret = 0;
out:
mutex_unlock(&deflate_mutex);
return ret;
}
static int jffs2_zlib_decompress(unsigned char *data_in,
unsigned char *cpage_out,
uint32_t srclen, uint32_t destlen)
{
int ret;
int wbits = MAX_WBITS;
mutex_lock(&inflate_mutex);
inf_strm.next_in = data_in;
inf_strm.avail_in = srclen;
inf_strm.total_in = 0;
inf_strm.next_out = cpage_out;
inf_strm.avail_out = destlen;
inf_strm.total_out = 0;
/* If it's deflate, and it's got no preset dictionary, then
we can tell zlib to skip the adler32 check. */
if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
((data_in[0] & 0x0f) == Z_DEFLATED) &&
!(((data_in[0]<<8) + data_in[1]) % 31)) {
jffs2_dbg(2, "inflate skipping adler32\n");
wbits = -((data_in[0] >> 4) + 8);
inf_strm.next_in += 2;
inf_strm.avail_in -= 2;
} else {
/* Let this remain D1 for now -- it should never happen */
jffs2_dbg(1, "inflate not skipping adler32\n");
}
if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
pr_warn("inflateInit failed\n");
mutex_unlock(&inflate_mutex);
return 1;
}
while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
;
if (ret != Z_STREAM_END) {
pr_notice("inflate returned %d\n", ret);
}
zlib_inflateEnd(&inf_strm);
mutex_unlock(&inflate_mutex);
return 0;
}
static struct jffs2_compressor jffs2_zlib_comp = {
.priority = JFFS2_ZLIB_PRIORITY,
.name = "zlib",
.compr = JFFS2_COMPR_ZLIB,
.compress = &jffs2_zlib_compress,
.decompress = &jffs2_zlib_decompress,
#ifdef JFFS2_ZLIB_DISABLED
.disabled = 1,
#else
.disabled = 0,
#endif
};
int __init jffs2_zlib_init(void)
{
int ret;
ret = alloc_workspaces();
if (ret)
return ret;
ret = jffs2_register_compressor(&jffs2_zlib_comp);
if (ret)
free_workspaces();
return ret;
}
void jffs2_zlib_exit(void)
{
jffs2_unregister_compressor(&jffs2_zlib_comp);
free_workspaces();
}
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