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Allow adjustment of http block device's readahead size, via a new 

":readahead=###:" suffix.

Signed-off-by: Nolan Leake <nolan <at> sigbus.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Nolan 2009-07-01 17:16:52 -07:00 committed by Anthony Liguori
parent 5f65049560
commit c76f4952bb
1 changed files with 47 additions and 3 deletions
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50
block/curl.c
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@ -71,6 +71,7 @@ typedef struct BDRVCURLState {
size_t len;
CURLState states[CURL_NUM_STATES];
char *url;
size_t readahead_size;
} BDRVCURLState;
static void curl_clean_state(CURLState *s);
@ -299,15 +300,57 @@ static int curl_open(BlockDriverState *bs, const char *filename, int flags)
BDRVCURLState *s = bs->opaque;
CURLState *state = NULL;
double d;
#define RA_OPTSTR ":readahead="
char *file;
char *ra;
const char *ra_val;
int parse_state = 0;
static int inited = 0;
file = strdup(filename);
s->readahead_size = READ_AHEAD_SIZE;
/* Parse a trailing ":readahead=#:" param, if present. */
ra = file + strlen(file) - 1;
while (ra >= file) {
if (parse_state == 0) {
if (*ra == ':')
parse_state++;
else
break;
} else if (parse_state == 1) {
if (*ra > '9' || *ra < '0') {
char *opt_start = ra - strlen(RA_OPTSTR) + 1;
if (opt_start > file &&
strncmp(opt_start, RA_OPTSTR, strlen(RA_OPTSTR)) == 0) {
ra_val = ra + 1;
ra -= strlen(RA_OPTSTR) - 1;
*ra = '\0';
s->readahead_size = atoi(ra_val);
break;
} else {
break;
}
}
}
ra--;
}
if ((s->readahead_size & 0x1ff) != 0) {
fprintf(stderr, "HTTP_READAHEAD_SIZE %Zd is not a multiple of 512\n",
s->readahead_size);
goto out_noclean;
}
if (!inited) {
curl_global_init(CURL_GLOBAL_ALL);
inited = 1;
}
dprintf("CURL: Opening %s\n", filename);
s->url = strdup(filename);
dprintf("CURL: Opening %s\n", file);
s->url = file;
state = curl_init_state(s);
if (!state)
goto out_noclean;
@ -346,6 +389,7 @@ out:
curl_easy_cleanup(state->curl);
state->curl = NULL;
out_noclean:
qemu_free(file);
return -EINVAL;
}
@ -401,7 +445,7 @@ static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
if (state->orig_buf)
qemu_free(state->orig_buf);
state->buf_start = start;
state->buf_len = acb->end + READ_AHEAD_SIZE;
state->buf_len = acb->end + s->readahead_size;
end = MIN(start + state->buf_len, s->len) - 1;
state->orig_buf = qemu_malloc(state->buf_len);
state->acb[0] = acb;