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fs: avoid using readv/writev where possible

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The VirtualBox shared file system doesn't seem to be capable of
`readv()` syscall. Since we don't need them in the most of the cases
anyway, it won't hurt to just use `read()` and `write()` when we are
reading just one buffer.

see https://github.com/joyent/node/issues/7343 for details.
This commit is contained in:
Fedor Indutny 2014-03-28 17:29:04 +04:00
parent 1d42b3ce7c
commit b48ca33019
1 changed files with 24 additions and 6 deletions
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30
src/unix/fs.c
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@ -217,9 +217,17 @@ skip:
static ssize_t uv__fs_read(uv_fs_t* req) {
ssize_t result;
if (req->off < 0)
result = readv(req->file, (struct iovec*) req->bufs, req->nbufs);
else {
if (req->off < 0) {
if (req->nbufs == 1)
result = read(req->file, req->bufs[0].base, req->bufs[0].len);
else
result = readv(req->file, (struct iovec*) req->bufs, req->nbufs);
} else {
if (req->nbufs == 1) {
result = pread(req->file, req->bufs[0].base, req->bufs[0].len, req->off);
goto done;
}
#if HAVE_PREADV
result = preadv(req->file, (struct iovec*) req->bufs, req->nbufs, req->off);
#else
@ -265,6 +273,8 @@ static ssize_t uv__fs_read(uv_fs_t* req) {
# endif
#endif
}
done:
if (req->bufs != req->bufsml)
free(req->bufs);
return result;
@ -583,9 +593,16 @@ static ssize_t uv__fs_write(uv_fs_t* req) {
pthread_mutex_lock(&lock);
#endif
if (req->off < 0)
r = writev(req->file, (struct iovec*) req->bufs, req->nbufs);
else {
if (req->off < 0) {
if (req->nbufs == 1)
r = write(req->file, req->bufs[0].base, req->bufs[0].len);
else
r = writev(req->file, (struct iovec*) req->bufs, req->nbufs);
} else {
if (req->nbufs == 1) {
r = pwrite(req->file, req->bufs[0].base, req->bufs[0].len, req->off);
goto done;
}
#if HAVE_PREADV
r = pwritev(req->file, (struct iovec*) req->bufs, req->nbufs, req->off);
#else
@ -632,6 +649,7 @@ static ssize_t uv__fs_write(uv_fs_t* req) {
#endif
}
done:
#if defined(__APPLE__)
pthread_mutex_unlock(&lock);
#endif