SUNRPC: move cache_detail->cache_request callback call to cache_read()
The reason to move cache_request() callback call from sunrpc_cache_pipe_upcall() to cache_read() is that this garantees, that cache access will be done userspace process context (only userspace process have proper root context). This is required for NFSd support in container: svc_export_request() (which is cache_request callback) calls d_path(), which, in turn, traverse dentry up to current->fs->root. Kernel threads always have global root, while container have be in "root jail" - i.e. have it's own nested root. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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21cd1254d3
Коммит
d94af6dea9
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@ -750,6 +750,18 @@ struct cache_reader {
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int offset; /* if non-0, we have a refcnt on next request */
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};
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static int cache_request(struct cache_detail *detail,
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struct cache_request *crq)
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{
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char *bp = crq->buf;
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int len = PAGE_SIZE;
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detail->cache_request(detail, crq->item, &bp, &len);
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if (len < 0)
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return -EAGAIN;
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return PAGE_SIZE - len;
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}
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static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
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loff_t *ppos, struct cache_detail *cd)
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{
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@ -784,6 +796,13 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
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rq->readers++;
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spin_unlock(&queue_lock);
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if (rq->len == 0) {
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err = cache_request(cd, rq);
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if (err < 0)
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goto out;
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rq->len = err;
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}
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if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
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err = -EAGAIN;
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spin_lock(&queue_lock);
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@ -1145,8 +1164,6 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
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char *buf;
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struct cache_request *crq;
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char *bp;
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int len;
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if (!detail->cache_request)
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return -EINVAL;
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@ -1166,19 +1183,10 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h)
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return -EAGAIN;
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}
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bp = buf; len = PAGE_SIZE;
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detail->cache_request(detail, h, &bp, &len);
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if (len < 0) {
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kfree(buf);
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kfree(crq);
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return -EAGAIN;
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}
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crq->q.reader = 0;
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crq->item = cache_get(h);
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crq->buf = buf;
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crq->len = PAGE_SIZE - len;
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crq->len = 0;
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crq->readers = 0;
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spin_lock(&queue_lock);
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list_add_tail(&crq->q.list, &detail->queue);
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