Я обнаружил, что vim продолжает посылать сигнал каким-то образом внутри cephfs, если он позволяет создать файл .swp из strace (заканчивается системным вызовом wirte) и gdb (кадр 1 равен write_eintr):
# define vim_write(fd, buf, count) write((fd), (char *)(buf), (size_t) (count))
...
/*
* Version of write() that retries when interrupted by EINTR (possibly
* by a SIGWINCH).
*/
long
write_eintr(int fd, void *buf, size_t bufsize)
{
long ret = 0;
long wlen;
/* Repeat the write() so long it didn't fail, other than being interrupted
* by a signal. */
while (ret < (long)bufsize)
{
wlen = vim_write(fd, (char *)buf + ret, bufsize - ret);
if (wlen < 0)
{
if (errno != EINTR)
break;
}
else
ret += wlen;
}
return ret;
}
#endif
IIU C, l oop просто продолжают пытаться вызвать запись, как только она прерывается по сигналу (и errno будет установлен на EINTR). Интересно, где находится EINTR set , поэтому я пытаюсь копаться в ядре и glib c.
kernel :
const struct file_operations ceph_file_fops = {
.open = ceph_open,
.release = ceph_release,
.llseek = ceph_llseek,
.read_iter = ceph_read_iter,
.write_iter = ceph_write_iter,
.mmap = ceph_mmap,
.fsync = ceph_fsync,
.lock = ceph_lock,
.flock = ceph_flock,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.unlocked_ioctl = ceph_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.fallocate = ceph_fallocate,
.copy_file_range = ceph_copy_file_range,
};
/*
* Take cap references to avoid releasing caps to MDS mid-write.
*
* If we are synchronous, and write with an old snap context, the OSD
* may return EOLDSNAPC. In that case, retry the write.. _after_
* dropping our cap refs and allowing the pending snap to logically
* complete _before_ this write occurs.
*
* If we are near ENOSPC, write synchronously.
*/
static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct ceph_file_info *fi = file->private_data;
struct inode *inode = file_inode(file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
struct ceph_osd_client *osdc = &fsc->client->osdc;
struct ceph_cap_flush *prealloc_cf;
ssize_t count, written = 0;
int err, want, got;
bool direct_lock = false;
u32 map_flags;
u64 pool_flags;
loff_t pos;
loff_t limit = max(i_size_read(inode), fsc->max_file_size);
if (ceph_snap(inode) != CEPH_NOSNAP)
return -EROFS;
prealloc_cf = ceph_alloc_cap_flush();
if (!prealloc_cf)
return -ENOMEM;
if ((iocb->ki_flags & (IOCB_DIRECT | IOCB_APPEND)) == IOCB_DIRECT)
direct_lock = true;
retry_snap:
if (direct_lock)
ceph_start_io_direct(inode);
else
ceph_start_io_write(inode);
/* We can write back this queue in page reclaim */
current->backing_dev_info = inode_to_bdi(inode);
if (iocb->ki_flags & IOCB_APPEND) {
err = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);
if (err < 0)
goto out;
}
err = generic_write_checks(iocb, from);
if (err <= 0)
goto out;
pos = iocb->ki_pos;
if (unlikely(pos >= limit)) {
err = -EFBIG;
goto out;
} else {
iov_iter_truncate(from, limit - pos);
}
count = iov_iter_count(from);
if (ceph_quota_is_max_bytes_exceeded(inode, pos + count)) {
err = -EDQUOT;
goto out;
}
err = file_remove_privs(file);
if (err)
goto out;
err = file_update_time(file);
if (err)
goto out;
inode_inc_iversion_raw(inode);
if (ci->i_inline_version != CEPH_INLINE_NONE) {
err = ceph_uninline_data(file, NULL);
if (err < 0)
goto out;
}
down_read(&osdc->lock);
map_flags = osdc->osdmap->flags;
pool_flags = ceph_pg_pool_flags(osdc->osdmap, ci->i_layout.pool_id);
up_read(&osdc->lock);
if ((map_flags & CEPH_OSDMAP_FULL) ||
(pool_flags & CEPH_POOL_FLAG_FULL)) {
err = -ENOSPC;
goto out;
}
dout("aio_write %p %llx.%llx %llu~%zd getting caps. i_size %llu\n",
inode, ceph_vinop(inode), pos, count, i_size_read(inode));
if (fi->fmode & CEPH_FILE_MODE_LAZY)
want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
else
want = CEPH_CAP_FILE_BUFFER;
got = 0;
err = ceph_get_caps(file, CEPH_CAP_FILE_WR, want, pos + count,
&got, NULL);
if (err < 0)
goto out;
dout("aio_write %p %llx.%llx %llu~%zd got cap refs on %s\n",
inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
(iocb->ki_flags & IOCB_DIRECT) || (fi->flags & CEPH_F_SYNC) ||
(ci->i_ceph_flags & CEPH_I_ERROR_WRITE)) {
struct ceph_snap_context *snapc;
struct iov_iter data;
spin_lock(&ci->i_ceph_lock);
if (__ceph_have_pending_cap_snap(ci)) {
struct ceph_cap_snap *capsnap =
list_last_entry(&ci->i_cap_snaps,
struct ceph_cap_snap,
ci_item);
snapc = ceph_get_snap_context(capsnap->context);
} else {
BUG_ON(!ci->i_head_snapc);
snapc = ceph_get_snap_context(ci->i_head_snapc);
}
spin_unlock(&ci->i_ceph_lock);
/* we might need to revert back to that point */
data = *from;
if (iocb->ki_flags & IOCB_DIRECT)
written = ceph_direct_read_write(iocb, &data, snapc,
&prealloc_cf);
else
written = ceph_sync_write(iocb, &data, pos, snapc);
if (direct_lock)
ceph_end_io_direct(inode);
else
ceph_end_io_write(inode);
if (written > 0)
iov_iter_advance(from, written);
ceph_put_snap_context(snapc);
} else {
/*
* No need to acquire the i_truncate_mutex. Because
* the MDS revokes Fwb caps before sending truncate
* message to us. We can't get Fwb cap while there
* are pending vmtruncate. So write and vmtruncate
* can not run at the same time
*/
written = generic_perform_write(file, from, pos);
if (likely(written >= 0))
iocb->ki_pos = pos + written;
ceph_end_io_write(inode);
}
if (written >= 0) {
int dirty;
spin_lock(&ci->i_ceph_lock);
ci->i_inline_version = CEPH_INLINE_NONE;
dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR,
&prealloc_cf);
spin_unlock(&ci->i_ceph_lock);
if (dirty)
__mark_inode_dirty(inode, dirty);
if (ceph_quota_is_max_bytes_approaching(inode, iocb->ki_pos))
ceph_check_caps(ci, 0, NULL);
}
dout("aio_write %p %llx.%llx %llu~%u dropping cap refs on %s\n",
inode, ceph_vinop(inode), pos, (unsigned)count,
ceph_cap_string(got));
ceph_put_cap_refs(ci, got);
if (written == -EOLDSNAPC) {
dout("aio_write %p %llx.%llx %llu~%u" "got EOLDSNAPC, retrying\n",
inode, ceph_vinop(inode), pos, (unsigned)count);
goto retry_snap;
}
if (written >= 0) {
if ((map_flags & CEPH_OSDMAP_NEARFULL) ||
(pool_flags & CEPH_POOL_FLAG_NEARFULL))
iocb->ki_flags |= IOCB_DSYNC;
written = generic_write_sync(iocb, written);
}
goto out_unlocked;
out:
if (direct_lock)
ceph_end_io_direct(inode);
else
ceph_end_io_write(inode);
out_unlocked:
ceph_free_cap_flush(prealloc_cf);
current->backing_dev_info = NULL;
return written ? written : err;
}
glib c:
/* Write NBYTES of BUF to FD. Return the number written, or -1. */
ssize_t
__libc_write (int fd, const void *buf, size_t nbytes)
{
if (nbytes == 0)
return 0;
if (fd < 0)
{
__set_errno (EBADF);
return -1;
}
if (buf == NULL)
{
__set_errno (EINVAL);
return -1;
}
__set_errno (ENOSYS);
return -1;
}
libc_hidden_def (__libc_write)
stub_warning (write)
weak_alias (__libc_write, __write)
libc_hidden_weak (__write)
weak_alias (__libc_write, write)
, ни один из них не установил errno в EINTR.